10.3. Alphabetical Listing of Keywords [P-S]

Table 10.3: Alphabetical Listing of Keywords [P-S]

Keyword	Definition
P1A Reactor Property	Pressure before the incident shock.
	Parameters	Optional/Reqd.	Units	Examples
	Pressure	Required	atm	P1A 1.0
	Keyword Usage	Optional Keyword. The shock velocity and any two of temperature, pressure, or density must be specified for conditions before the incident shock. See also T1 and RHO1 .
	Reactor Models	Normal Incident Shock Normal Reflected Shock
P2A Reactor Property	Pressure after the incident shock.
	Parameters	Optional/Reqd.	Units	Examples
	Pressure	Required	atm	P2A 2.3
	Keyword Usage	Optional Keyword. Any two of temperature, pressure, or density must be specified for conditions after the incident shock. See also T2 and RHO2 .
	Reactor Models	Normal Incident Shock Normal Reflected Shock
P3A Reactor Property	Pressure after the reflected shock, given as in the equations.
	Parameters	Optional/Reqd.	Units	Examples
	Pressure	Required	atm	P3A 2.3
	Keyword Usage	Optional Keyword. Any two of temperature, pressure, or density must be specified for conditions before the reflected shock. See also T3 and RHO3 .
	Reactor Models	Normal Reflected Shock
PARP Output	Partial-pressures of the gas-phase species will be used in the diagnostic output file.
	Keyword Usage	Optional keyword. By default, mass fractions are printed, not partial pressures.
	Reactor Models	Cylindrical Shear Flow Reactor Planar Shear Flow Reactor
PBDEN Output	This keyword resets all bulk species densities defined in the surface mechanism to the value given by this keyword.
	Parameters	Optional/Reqd.	Units	Examples
	material_name	Required	None	PBDEN ligA 2.15
	bulk_density	Required	g/cm³	PBDEN ligA 2.15
	Keyword Usage	Optional keyword.
	Reactor Models	Closed Homogeneous Reactor Perfectly Stirred Reactor (PSR) Plug Flow Reactor (PFR)
PDF Output	Request the probability distribution of a scalar to be output to a pdf.plt file. Any number of PDF entries is allowed.
	Parameters	Optional/Reqd.	Units	Examples
	Scalar (temperature or species name)	Required	--	PDF T
	Keyword Usage	Optional keyword. By default, no PDF is printed.
	Reactor Models	Closed Partially Stirred Reactor (PaSR) Partially Stirred Reactor (PaSR)
PENG Reactor Property	Include the energy conservation equation for particles.
	Keyword Usage	Optional keyword.
	Reactor Models	Opposed-flow Flame Premixed Laminar Burner-stabilized Flame Premixed Laminar Flame-speed Calculation
PEST Reactor Property	Specifies an estimate of the equilibrium pressure.
	Parameters	Optional/Reqd.	Units	Examples
	Pressure	Required	atm	PEST 1.1
	Keyword Usage	Optional keyword. May help convergence to the equilibrium pressure, or assure an appropriate equilibrium pressure is calculated when a second, trivial solution exists.
	Reactor Models	Chemical and Phase Equilibrium Calculations
PFAL Output	Analyze the pressure fall-off of a gas phase reaction, that is, creates a table of reaction rates versus total gas pressure at a constant temperature. The ALL option is the default and produces tables for every gas-phase reaction. The NONE option suppresses output for all of the reactions. If reaction information is desired for only certain reactions, they may be optionally specified by their number (given in the Pre-processor output) or by typing an exact duplicate of the reaction expression (see example input).
	Parameters	Optional/Reqd.	Units	Examples
	ALL option	Optional, default is ALL	--	PFAL ALL
	NONE option	Optional, default is ALL	--	PFAL NONE
	Gas reaction number list	Optional, default is ALL	--	PFAL 2 5
	Gas reaction expression	Optional, default is ALL	--	PFAL 2CH3(+M)<=>C2H6(+M)
	Keyword Usage	Optional keyword. By default, the table output is determined by the ALL or NONE keyword.
	Reactor Models	Mechanism Analyzer
PFLR Reactor Property	Set the minimum bounds of the particle moments to a slightly negative number to allow the solver more room to search for a solution.
	Parameters	Optional/Reqd.	Units	Examples
	Minimum bound	Required	--	PFLR -1.0d-06
	Keyword Usage	Optional keyword.
	Reactor Models	Opposed-flow Flame Premixed Laminar Burner-stabilized Flame Premixed Laminar Flame-speed Calculation
PH Problem Type	Constant pressure and enthalpy constraints.
	Keyword Usage	Optional keyword. Exactly one problem type keyword must be included.
	Reactor Models	Chemical and Phase Equilibrium Calculations
	Notes	HP keyword is equivalent.
PHASE_MASSOUTFLOWRATE Reactor Property	Specified mass outflow rate of the phase.
	Parameters	Optional/Reqd.	Units	Examples
	phase name	Required		PHASE_MASSOUTFLOWRATE urea 0.0
	mass outflow rate of the phase	Required	g/sec	PHASE_MASSOUTFLOWRATE urea 0.0
	Keyword Usage	Optional keyword. Bulk name must follow the keyword. "Gas" is not valid for the keyword.
	Reactor Models	Multiphase PSR
PHASE_MOLAROUTFLOWRATE Reactor Property	Specified molar outflow rate of the phase.
	Parameters	Optional/Reqd.	Units	Examples
	phase name	Required		PHASE_MOLAROUTFLOWRATE urea 0.0
	molar outflow rate of the phase	Required	mole/sec	PHASE_MOLAROUTFLOWRATE urea 0.0
	Keyword Usage	Optional keyword. Bulk name must follow the keyword. "Gas" is not valid for the keyword.
	Reactor Models	Multiphase PSR
PHASE_VOLOUTFLOWRATE Reactor Property	Specified volumetric outflow rate of the phase.
	Parameters	Optional/Reqd.	Units	Examples
	phase name	Required		PHASE_VOLOUTFLOWRATE urea 0.0
	volumetric outflow rate of the phase	Required	cm³/sec	PHASE_VOLOUTFLOWRATE urea 0.0
	Keyword Usage	Optional keyword. Bulk name must follow the keyword. "Gas" is not valid for the keyword.
	Reactor Models	Multiphase PSR Reactor
PHASE_VOLUME Reactor Property	Specified volume of the phase.
	Parameters	Optional/Reqd.	Units	Examples
	phase name	Required		PHASE_VOLUME urea 10.0
	volume of the phase	Required	cm³	PHASE_VOLUME urea 10.0
	Keyword Usage	Optional keyword. Bulk name must follow the keyword. "Gas" is not valid for the keyword.
	Reactor Models	Multiphase PSR
PHIA Reactor Property	Set the upper limit of the pressure range (in atmospheres) in tables where the gas pressure is varied.
	Parameters	Optional/Reqd.	Units	Examples
	Pressure	Required	atm	PHIA 2.
	Keyword Usage	Optional keyword. By default, the pressure is 1.315789 atm (1000 Torr).
	Reactor Models	Mechanism Analyzer
	Notes	In previous versions, keyword PHIG was used with units of Torr
PLAN Reactor Property	Use a planar coordinate system, which is appropriate for a Tsuji burner configuration.
	Keyword Usage	Optional keyword. By default, the coordinate system is radial and axisymmetric.
	Reactor Models	Diffusion or Premixed Opposed-flow Flame
PLAT Reactor Property	Use a plateau profile to set up initial solution estimates, rather than a linear profile.
	Keyword Usage	Optional keyword. By default, the plateau profile is used.
	Reactor Models	Diffusion or Premixed Opposed-flow Flame
PLOA Reactor Property	Set the lower limit of the pressure range (in atmospheres) in tables where the gas pressure is varied.
	Parameters	Optional/Reqd.	Units	Examples
	Pressure	Required	atm	PLOA 1.0
	Keyword Usage	Optional keyword. By default, the pressure is 0.001315789 atm (1 Torr)
	Reactor Models	Mechanism Analyzer
	Notes	In previous versions, keyword PLOW was used with units of Torr
PLUG Reactor Property	Indicates that plug-flow equations will be solved and that the Reactor Model will be one of the family of Plug Flow Reactors.
	Keyword Usage	Required keyword.
	Reactor Models	Honeycomb Reactor Plasma Plug Flow Reactor Plug Flow Reactor
PNDE Reactor Property	Assigns the initial (or estimate for steady-state calculations) number density of the particle consisting of the designated bulk species. The default value is 0. The reactor number is optional. When no reactor number is given, the same initial number density will apply to all reactors in the network. If neither PVFE nor PROE is given, the initial/estimate values of the moments are computed as
	Parameters	Optional/Reqd.	Units	Examples
	Material name	Required	--	PNDE CARBON 1.0E10 4
	Number density	Required	particles/cm³	PNDE CARBON 1.0E10 4
	Reactor number	Optional	--	PNDE CARBON 1.0E10 4
	Keyword Usage	Optional keyword. The default value is value for the number density is 0.
	Reactor Models	Closed Homogeneous Batch Reactor Closed Plasma Reactor Cylindrical Shear Flow Reactor Honeycomb Monolith Reactor IC HCCI Engine Perfectly Stirred Reactor (PSR) Planar Shear Flow Reactor Plasma PSR Plasma Plug Flow Reactor Plug Flow Reactor SI Engine Zonal Simulator
PNDI Inlet Property	Assigns the number density of the particle consisting of the designated material name to the named inlet stream. The default value is 0. The stream name is optional if there is only one inlet.
	Parameters	Optional/Reqd.	Units	Examples
	Stream name	Optional if only one inlet.	--	PNDI exhaust CARBON 1.0E12
	Material name	Required	--	PNDI exhaust CARBON 1.0E12
	Mass density	Required	particles/cm³	PNDI exhaust CARBON 1.0E12
	Keyword Usage	Optional keyword. The default value for the mass density is 0.
	Reactor Models	Cylindrical Shear Flow Reactor Honeycomb Monolith Reactor Perfectly-stirred Reactor (PSR) Planar Shear Flow Reactor Plasma PSR Plasma Plug Flow Reactor Plug-flow Reactor (PFR)
PNUM Reactor Property	Set the total number of pressure entries in tables where the gas pressure is varied. The default is 10. Note that the changes in the pressure are determined on a logarithmic scale.
	Parameters	Optional/Reqd.	Units	Examples
	Number of pressures	Required	--	PNUM 10
	Keyword Usage	Optional keyword. By default, the number of pressures is 10.
	Reactor Models	Mechanism Analyzer
POLN1 Reactor Property	Specify intake-side piston pin offset distance (optional).
	Parameters	Optional/Reqd.	Units	Examples
	Offset distance	Required	cm	POLN1 0.5
	Keyword Usage	Optional keyword. Optional for use with OPMV or OPOC. Default value = 0.0.
	Reactor Models	Direct Injection Diesel Engine Simulator IC HCCI Engine Multi-Zone HCCI Engine SI Engine Zonal Simulator
POLN2 Reactor Property	Specify exhaust-side piston pin offset distance (optional).
	Parameters	Optional/Reqd.	Units	Examples
	Offset distance	Required	cm	POLN2 1.1
	Keyword Usage	Optional keyword. Optional for use with OPMV or OPOC. Default value = 0.0.
	Reactor Models	Direct Injection Diesel Engine Simulator IC HCCI Engine Multi-Zone HCCI Engine SI Engine Zonal Simulator
PPRO Reactor Property Profiles	Reactor pressure profile specified as a function of time for transient 0-D homogeneous systems or as a function of distance for Plug Flow Reactors.
	Parameters	Optional/Reqd.	Units	Examples
	Time or Distance value, depending on Reactor Model	Required	sec or cm	PPRO 1.0E-4 1.0
	Pressure	Required	atm	PPRO 1.0E-4 1.0
	Reactor number (PSR clusters only)	Optional If no number is given, the profile described by the first two values is assumed to apply to all reactors in a cluster.	--	PPRO 1.0E-4 1.0 1
	Keyword Usage	Optional keyword. By default, no profile is provided.
	Reactor Models	Closed Homogeneous Batch Reactor Closed Plasma Reactor Diffusion or Premixed Opposed-flow Flame Honeycomb Reactor Non-reactive Gas Mixer Perfectly Stirred Reactor (PSR) Plasma Plug Flow Reactor Plasma PSR Multiphase PSR Plug Flow Reactor
PRDL Reactor Property	The Prandlt number used in the generalized heat transfer correlation.
	Parameters	Optional/Reqd.	Units	Examples
	Prandlt number	Required	--	PRDL 0.77
	Keyword Usage	Optional keyword. By default, the value is 0.7.
	Reactor Models	IC HCCI Engine SI Engine Zonal Simulator
PRES Reactor Property	The reactor pressure in atmospheres. Depending on the Reactor Model and problem type, the pressure specified can serve as the pressure constraint (for constant-pressure problems), as an initial guess for pressure (for steady-state problems where pressure is a variable), or as the initial reactor pressure (for transient cases where pressure is a variable). For the Mechanism Analyzer, this is the bath-gas pressure.
	Parameters	Optional/Reqd.	Units	Examples
	Reactor pressure	Required	atm	PRES 1.0
	Reactor number (PSR clusters only)	Optional If no number is given, the keyword is assumed to apply to all reactors in a cluster.	--	PRES 1.0 1
	Keyword Usage	Required keyword in most cases. Optional keyword only for Mechanism Analyzer, where the default is 1 atm.
	Reactor Models	Chemical and Phase Equilibrium Calculations Closed Homogeneous Batch Reactor Closed Partially Stirred Reactor (PaSR) Closed Plasma Reactor Cylindrical Shear Flow Reactor Diffusion or Premixed Opposed-flow Flame Honeycomb Reactor IC HCCI Engine Mechanism Analyzer Non-reactive Gas Mixer Partially Stirred Reactor (PaSR) Perfectly Stirred Reactor (PSR) Planar Shear Flow Reactor Plasma Plug Flow Reactor Plasma PSR Multiphase PSR Plug Flow Reactor Premixed Laminar Burner-stabilized Flame Premixed Laminar Flame-speed Calculation Rotating Disk CVD Reactor SI Engine Zonal Simulator Stagnation Flow CVD Reactor
	Notes	In previous version, PRMT was an alternate keyword that allowed pressure input in millitorr units, for 0-D homogeneous and plug-flow systems only. In previous versions, this was PBTH for the Mechanism Analyzer.
PRMN Reactor Property	Minimum mole fraction value applied to the estimated values of the flame products, when the (default) equilibrium is used to determine product estimates. Ignored in the case that PROD2 keywords are present.
	Parameters	Optional/Reqd.	Units	Examples
	Product fraction	Required	mole fractions	PRMN 1.0E-10
	Keyword Usage	Optional keyword. By default, the flame product fraction is set to 0.
	Reactor Models	Premixed Laminar Burner-stabilized Flame Premixed Laminar Flame-speed Calculation
PRNT Output	Printing control. "PRNT 0" provides printed output for only the solution (plus sensitivity coefficients and rates-of-production coefficients, when requested). "PRNT 1" provides an additional summary of the iteration path from the solver. "PRNT 2" includes printing at every stage of the Twopnt solver’s Newton iteration and time stepping procedure. More printing is sometimes helpful when diagnosing problems and trying to adjust the input parameters to optimize convergence. However, since the increased printing requires more function evaluations to show how the solution is progressing, the computer time increases with increased printing.
	Parameters	Optional/Reqd.	Units	Examples
	Print control number	Required	--	PRNT 1
	Keyword Usage	Optional keyword. By default, the print control is set to 1.
	Reactor Models	Closed Homogeneous Batch Reactor Closed Plasma Reactor Cylindrical Shear Flow Reactor Diffusion or Premixed Opposed-flow Flame Honeycomb Reactor IC HCCI Engine Non-reactive Gas Mixer Perfectly Stirred Reactor (PSR) Planar Shear Flow Reactor Plasma Plug Flow Reactor Plasma PSR Plug Flow Reactor Premixed Laminar Burner-stabilized Flame Premixed Laminar Flame-speed Calculation Rotating Disk CVD Reactor SI Engine Zonal Simulator Stagnation Flow CVD Reactor
PROD Reactor Property	Estimated values of the gas-phase mole fractions at the far end of the domain (that is, the deposition surface for CVD reactors or the burned state at XEND for Premixed Laminar Flames) or in the middle of the flame (for Opposed-flow Flames). The sum of the product mole fractions should equal to 1.0; if they do not, then a warning message will be printed to the diagnostic output file and the mole fractions will be normalized so that they do sum to one.
	Parameters	Optional/Reqd.	Units	Examples
	Species name	Required	--	PROD H2O 0.5
	Mole fraction	Required	--	PROD H2O 0.5
	Keyword Usage	Optional keyword. If PROD2 keywords are not provided, then an equilibrium calculation will be used to determine the estimated product composition (see also PRMN).
	Reactor Models	Diffusion or Premixed Opposed-flow Flame Premixed Laminar Burner-stabilized Flame Premixed Laminar Flame-speed Calculation Rotating Disk CVD Reactor Stagnation Flow CVD Reactor
	Notes	Any given species may simultaneously be included as a reactant (REAC), intermediate (INTM), and product (PROD2). The PROD2 keywords must be changed as a set, not individually for a restart run. The PROD2 keywords must be changed as a set, not individually for continuation run.
PROE Reactor Property	Assigns the initial (or estimate for steady-state calculations) number density of the particle consisting of the designated material name. The default value is 0. The reactor number is optional. When no reactor number is given, the same initial particle mass density will apply to all reactors in the network. The PROE keyword must be used in conjunction with the PNDE keyword and is mutually exclusive to keyword PVFE. When both PNDE and PROE are given, the moments are calculated as where is the mass of a material name molecule and is the mass density of the bulk material.
	Parameters	Optional/Reqd.	Units	Examples
	Material name	Required	--	PROE CARBON 1.0E-10 1
	Mass density	Required	gm/cm³	PROE CARBON 1.0E-10 1
	Reactor number	Optional	--	PROE CARBON 1.0E-10 1
	Keyword Usage	Optional keyword. The default value for the mass density is 0. PNDE keyword required. Cannot be used with PVFE.
	Reactor Models	Closed Homogeneous Batch Reactor Closed Plasma Reactor Cylindrical Shear Flow Reactor Honeycomb Monolith Reactor IC HCCI Engine Perfectly Stirred Reactor (PSR) Planar Shear Flow Reactor Plasma PSR Plasma Plug Flow Reactor Plug Flow Reactor SI Engine Zonal Simulator
PROI Inlet Property	Assigns the mass density of the particle consisting of the designated material name to the named inlet stream. The default value is 0. The stream name is optional if there is only one inlet. The PROI keyword must be used in conjunction with the PNDI keyword and is mutually exclusive to keyword PVFI.
	Parameters	Optional/Reqd.	Units	Examples
	Stream name	Optional if there is only one inlet.	--	PROI EGR CARBON 1.0E-10
	Material name	Required	--	PROI EGR CARBON 1.0E-10
	Number density	Required	gm/cm³	PROI EGR CARBON 1.0E-10
	Keyword Usage	Optional keyword. Must be used with PNDI. Cannot be used with PVFI. The default value for the number density is 0.
	Reactor Models	Cylindrical Shear Flow Reactor Honeycomb Monolith Reactor Perfectly-stirred Reactor (PSR) Planar Shear Flow Reactor Plasma PSR Plasma Plug Flow Reactor Plug-flow Reactor (PFR)
PS Problem Type	Constant pressure and entropy constraints.
	Keyword Usage	Optional keyword. Exactly one problem-type keyword must be included.
	Reactor Models	Chemical and Phase Equilibrium Calculations
	Notes	SP keyword.is equivalent.
PSBAR Reactor Property	The piston head area to bore area ratio.
	Parameters	Optional/Reqd.	Units	Examples
	Ratio of piston head area to bore area.	Required	None	PSBAR 1.1
	Keyword Usage	Optional keyword. Default = 1.0.
	Reactor Models	IC HCCI Engine Multi-zone HCCI Engine SI Engine Zonal Simulator
	Notes	PSBAR should be > 1.0.
PSURF Inlet Property	Initial surface coverage on particles by the surface site species in the inlet flow.
	Parameters	Optional/Reqd.	Units	Examples
	Stream name	Optional if there is only one inlet.	--	PSURF inlet1 C(S) 0.1
	Surface species name	Required	--	PSURF inlet1 C(S) 0.1
	Surface coverage	Required	--	PSURF inlet1 C(S) 0.1
	Keyword Usage	Optional keyword
	Reactor Models	Honeycomb Reactor Opposed-flow Flame Perfectly Stirred Reactor (PSR) Plasma Plug Flow Reactor Plasma PSR Plug Flow Reactor Premixed Laminar Burner-stabilized Flame Premixed Laminar Flame-speed Calculation
PSV Solver	Pseudo-velocity for use in modifying the surface species equations for improved convergence. This pseudo-convection term is incorporated into the surface site fraction equations in order to convert algebraic equations to differential equations. The value of the PSV should be small enough such that it has no effect on the solution results, but large enough to affect the convergence behavior. If not supplied, then the unmodified equations are used. The modified equations are sometimes helpful in reaching steady-state conditions for problems with stiff surface chemistry (e.g. catalytic combustion), but should not be used if no convergence problems are encountered. A recommended value to try for PSV would be about 1/10th of the inlet velocity, but the simulation should be repeated with smaller or larger values to make sure that it has no effect on the solution.
	Parameters	Optional/Reqd.	Units	Examples
	Pseudo-velocity	Required	cm/sec	PSV 10.
	Keyword Usage	Optional keyword. By default, the value is set to 10* ATOL.
	Reactor Models	Honeycomb Reactor Plasma Plug Flow Reactor Plug Flow Reactor
PTM_SECTION_NUM Reactor Property	The number of sections to use for the specified material.
	Parameters	Optional/Reqd.	Units	Examples
	Material name	Required	--	PTM_SECTION_NUM SOOT 30
	Number of sections	Required	--	PTM_SECTION_NUM SOOT 30
	Keyword Usage	Required when the Sectional Model is used.
	Reactor Models	Opposed-flow Flame Plug Flow Reactor Premixed Laminar Burner Stabilized Flame Premixed Laminar Burner Stabilized Stagnation Flame Premixed Laminar Flame Speed Calculator
PTM_SECTION_SIZEDEP_A0 Reactor Property	Tanh function constant that is used to blend lower and upper bounds of collision efficiency.
	Parameters	Optional/Reqd.	Units	Examples
	Material name	Required	None	PTM_SECTION_SIZEDEP_A0 SOOT 5
	A0	Required	None	PTM_SECTION_SIZEDEP_A0 SOOT 5
	Keyword Usage	Optional keyword. Default size is 7.
	Reactor Models	Closed Homogeneous Batch Reactor Internal Combustion Engine Perfectly Stirred Reactor (PSR) Diffusion or Premixed Opposed Flow Flame Plug Flow Reactor Premixed Laminar Burner Stabilized Flame Premixed Laminar Burner Stabilized Stagnation Flame Premixed Laminar Flame Speed Calculator
PTM_SECTION_SIZEDEP_COLEFF Reactor Property	Use size-dependent collision efficiency for particles .
	Parameters	Optional/Reqd.	Units	Examples
	Material name	Required	None	PTM_SECTION_SIZEDEP_COLEFF SOOT
	Keyword Usage	Optional keyword. Not used by default.
	Reactor Models	Closed Homogeneous Batch Reactor Internal Combustion Engine Perfectly Stirred Reactor (PSR) Diffusion or Premixed Opposed Flow Flame Plug Flow Reactor Premixed Laminar Burner Stabilized Flame Premixed Laminar Burner Stabilized Stagnation Flame Premixed Laminar Flame Speed Calculator
PTM_SECTION_SIZEDEP_DSTAR Reactor Property	Limit diameter for size-dependent collision efficiency.
	Parameters	Optional/Reqd.	Units	Examples
	Material name	Required	None	PTM_SECTION_SIZEDEP_DSTAR SOOT 13-06
	Diameter	Required	None	PTM_SECTION_SIZEDEP_DSTAR SOOT 13-06
	Keyword Usage	Optional keyword. No default value is given and must be specified by user when using size-dependent collision efficiency. For soot simulation, the value generally ranges from 10 to 20 nm.
	Reactor Models	Closed Homogeneous Batch Reactor Internal Combustion Engine Perfectly Stirred Reactor (PSR) Diffusion or Premixed Opposed Flow Flame Plug Flow Reactor Premixed Laminar Burner Stabilized Flame Premixed Laminar Burner Stabilized Stagnation Flame Premixed Laminar Flame Speed Calculator
PTM_SECTION_SIZEDEP_HAMAKER Reactor Property	Hamaker constant for computing potential well depth when using size-dependent collision efficiency for particles.
	Parameters	Optional/Reqd.	Units	Examples
	Material name	Required	None	PTM_SECTION_SIZEDEP_HAMAKER SOOT 5e-13
	Diameter	Required	None	PTM_SECTION_SIZEDEP_HAMAKER SOOT 5e-13
	Keyword Usage	Optional keyword. Default value is 7e-13 erg.
	Reactor Models	Closed Homogeneous Batch Reactor Internal Combustion Engine Perfectly Stirred Reactor (PSR) Diffusion or Premixed Opposed Flow Flame Plug Flow Reactor Premixed Laminar Burner Stabilized Flame Premixed Laminar Burner Stabilized Stagnation Flame Premixed Laminar Flame Speed Calculator
PTM_SECTION_SN0 Reactor Property	Number of "atoms" in the smallest section for the specified material. When etching reactions are present, the number of sectional atoms parameter needs to be unity. When only growth is present, the user can give some higher value to avoid calculations for smaller particles that will never be present. However, this value must not be greater than the number of atoms in the smallest nucleating particle.
	Parameters	Optional/Reqd.	Units	Examples
	Material name	Required	--	PTM_SECTION_SN0 SOOT 1
	Number of sectional "atoms"	Required	--	PTM_SECTION_SN0 SOOT 1
	Keyword Usage	Required when the Sectional Model is used.
	Reactor Models	Opposed-flow Flame Plug Flow Reactor Premixed Laminar Burner Stabilized Flame Premixed Laminar Burner Stabilized Stagnation Flame Premixed Laminar Flame Speed Calculator
PTM_SECTION_SPACING Reactor Property	Geometric spacing factor to be used for sections.
	Parameters	Optional/Reqd.	Units	Examples
	Material name	Required	--	PTM_SECTION_SPACING CARBON 2.0
	Geometric spacing factor	Required	--	PTM_SECTION_SPACING CARBON 2.0
	Keyword Usage	Required when the Sectional Model is used.
	Reactor Models	Opposed-flow Flame Plug Flow Reactor Premixed Laminar Burner Stabilized Flame Premixed Laminar Burner Stabilized Stagnation Flame Premixed Laminar Flame Speed Calculator
PTM_SECTION_TCOND Reactor Property	Thermal conductivity of particle material. This is a required input when any of the flame models are using the Sectional Model with thermophoresis.
	Parameters	Optional/Reqd.	Units	Examples
	Material name	Required	--	PTM_SECTION_TCOND CARBON 2.0E+05
	Thermal conductivity of "material"	Required	erg/s-cm-K	PTM_SECTION_TCOND CARBON 2.0E+05
	Keyword Usage	Required when the Sectional Model with thermophoresis is used.
	Reactor Models	Opposed-flow Flame Plug Flow Reactor Premixed Laminar Burner Stabilized Flame Premixed Laminar Burner Stabilized Stagnation Flame Premixed Laminar Flame Speed Calculator
PTM_SECTION_USERBULKROP Reactor Property	User-specified enhancement factor for the growth/etching reactions on particles. This can be used only with the sectional method. Note that the user-routines library must be compiled and linked; see the Chemkin Application Programming Interface Manual for details.
	Parameters	Optional/Reqd.	Units	Examples
	Material name	Required	None	PTM_SECTION_USERBULKROP CARBON
	Keyword Usage	Optional keyword. Not used by default.
	Reactor Models	Closed Homogeneous Batch Reactor IC HCCI Engine Multi-Zone HCCI Engine Simulator SI Engine Zonal Simulator Perfectly Stirred Reactor (PSR) Plug Flow Reactor Opposed-flow Flame Premixed Laminar Burner Stabilized Flame Premixed Laminar Burner Stabilized Stagnation Flame Premixed Laminar Flame Speed Calculator
PTM_SECTIONAL Reactor Property	Signals that sectional model is to be used. This is a required keyword when the Sectional Model is used.
	Keyword Usage	Required when the Sectional Model is used.
	Reactor Models	Closed Homogeneous Batch Reactor IC HCCI Engine Multi-Zone HCCI Engine Simulator SI Engine Zonal Simulator Perfectly Stirred Reactor (PSR) Opposed-flow Flame Plug Flow Reactor Premixed Laminar Burner Stabilized Flame Premixed Laminar Burner Stabilized Stagnation Flame Premixed Laminar Flame Speed Calculator
PV Problem Type	Constant pressure and volume constraints.
	Keyword Usage	Optional keyword. Exactly one problem-type keyword must be included.
	Reactor Models	Chemical and Phase Equilibrium Calculations
	Notes	VP keyword is equivalent.
PVFE Reactor Property	Assigns the initial (or estimate for steady state calculations) number density of the particle consisting of the designated material name. The default value is 0. The reactor number is optional. When no reactor number is given, the same initial particle volume fraction will apply to all reactors in the network. The PVFE keyword must be used in conjunction with the PNDE keyword and is mutually exclusive to keyword PROE. When both PNDE and PVFE are given, the moments are calculated as where is the mass of a material name molecule and is the mass density of the bulk material.
	Parameters	Optional/Reqd.	Units	Examples
	Material name	Required	--	PVFE CARBON 1.0E-10 4
	Volume fraction	Required	cm³/cm³	PVFE CARBON 1.0E-10 4
	Reactor number	Optional	--	PVFE CARBON 1.0E-10 4
	Keyword Usage	Optional keyword. The default value is value for the volume fraction is 0. PNDE keyword required.
	Reactor Models	Closed Homogeneous Batch Reactor Closed Plasma Reactor Cylindrical Shear Flow Reactor Honeycomb Monolith Reactor IC HCCI Engine Perfectly Stirred Reactor (PSR) Planar Shear Flow Reactor Plasma PSR Plasma Plug Flow Reactor Plug Flow Reactor SI Engine Zonal Simulator
PVFI Inlet Property	Assigns the volume fraction of the particle consisting of the designated material name to the named inlet stream. The default value is 0. The stream name is optional if there is only one inlet. The PVFI keyword must be used in conjunction with the PNDI keyword and is mutually exclusive to keyword PROI.
	Parameters	Optional/Reqd.	Units	Examples
	Stream name	Optional if there is only one inlet.	--	PVFI inlet1 CARBON 1.0E--9
	Material name	Required	--	PVFI inlet1 CARBON 1.0E-9
	Number density	Required	cm³ /cm³	PVFI inlet1 CARBON 1.0E-9
	Keyword Usage	Optional keyword. Must be used with PNDI. Cannot be used with PROI. The default value for the number density is 0.
	Reactor Models	Cylindrical Shear Flow Reactor Honeycomb Monolith Reactor Perfectly-stirred Reactor (PSR) Planar Shear Flow Reactor Plasma PSR Plasma Plug Flow Reactor Plug-flow Reactor (PFR)
PVS0 Reactor Property	Specify the reference gas viscosity at the reference temperature of the power-law for viscosity.
	Parameters	Optional/Reqd.	Units	Examples
	Reference gas viscosity at reference temperature	Required.	g/cm-s	PVS0 1.716E-4
	Keyword Usage	Optional.
	Reactor Models	Multi-Zone HCCI Simulator IC HCCI Engine SI Engine Zonal Simulator
PVSN Reactor Property	Specify the exponent of the temperature ratio term of the power-law for viscosity.
	Parameters	Optional/Reqd.	Units	Examples
	Exponent of temperature ratio term	Required.	--	PVSN 0.5
	Keyword Usage	Optional.
	Reactor Models	Multi-Zone HCCI Simulator IC HCCI Engine SI Engine Zonal Simulator
PVST Reactor Property	Specify the reference temperature of the power-law for viscosity.
	Parameters	Optional/Reqd.	Units	Examples
	Reference temperature	Required.	K	PVST 273.15
	Keyword Usage	Optional.
	Reactor Models	Multi-Zone HCCI Simulator IC HCCI Engine SI Engine Zonal Simulator
PWRC Reactor Property	The power being supplied to heat the deposition surface or disk. This value is used only if the disk temperature is being calculated from an energy balance by including keyword RADB . See Equation 15–18 of the Chemkin Theory Manual .
	Parameters	Optional/Reqd.	Units	Examples
	Power	Required	cal/(cm² ⋅ sec)	PWRC 15.E7
	Keyword Usage	Optional keyword. By default, the power is 0.0.
	Reactor Models	Rotating Disk CVD Reactor Stagnation Flow CVD Reactor
PWRW Reactor Property	Total power deposition to the plasma.
	Parameters	Optional/Reqd.	Units	Examples
	Total power deposition	Required	Watts	PWRW 1000.
	Reactor number (PSR clusters only)	Optional If no number is given, the value is assumed to apply to all reactors in a cluster.	--	PWRW 1000. 1
	Keyword Usage	Required keyword.
	Reactor Models	Closed Plasma Reactor Plasma Plug Flow Reactor Plasma PSR
QDOT Reactor Property	The power being supplied to heat the gas as a spatially distributed Gaussian heat source. QDOT is the total power, that is, the spatial integral of the heat source function. See Equation 15–14 of the Chemkin Theory Manual .
	Parameters	Optional/Reqd.	Units	Examples
	Power	Required	erg/(cm² ⋅ sec)	QDOT 1.0E7
	Keyword Usage	Optional keyword. By default, the power is 0.0.
	Reactor Models	Rotating Disk CVD Reactor Stagnation Flow CVD Reactor
QDTC Reactor Property	The power being supplied to heat the gas as a spatially distributed Gaussian heat source. QDTC is the total power, that is, the spatial integral of the heat source function. See Equation 15–14 of the Chemkin Theory Manual .
	Parameters	Optional/Reqd.	Units	Examples
	Power	Required	cal/(cm² ⋅ sec)	QDTC 1.0E7
	Keyword Usage	Optional keyword. By default, the power is 0.0.
	Reactor Models	Rotating Disk CVD Reactor Stagnation Flow CVD Reactor
QEXP Reactor Property	Specifies the gas chemistry heat release rate that defines the start of the expansion period. This keyword will take effect only when the gas heat release equation is solved (activated by keyword: QRGEQ ).
	Parameters	Optional/Reqd.	Units	Examples
	heat_release_rate	Required	cal/sec	QEXP 0.5
	Keyword Usage	Optional keyword. Default is 0.1 cal/sec.
	Reactor Models	Multi-Zone HCCI Simulator IC HCCI Engine SI Engine Zonal Simulator
QFUN Reactor Property User Subroutine	Reactor heat loss will be given as a specified function of time (for 0-D homogeneous reactors) or as a function of distance (for Plug Flow Reactors), through a user-programmed subroutine. FUNCTION PSQFUN (LENIQ, LENRQ, IQFUN, RQFUN) must be provided to specify the heat loss and linked to the application program. See the Application Programming Interface Manual for details on how to work with user subroutines.
	Keyword Usage	Optional keyword. By default, the value there is no heat loss from the reactor. The units returned from the user subroutine must be in erg/sec. See also QPRO.
	Reactor Models	Closed Homogeneous Batch Reactor Closed Plasma Reactor Diffusion or Premixed Opposed-flow Flame Honeycomb Reactor IC HCCI Engine Non-reactive Gas Mixer Perfectly Stirred Reactor (PSR) Plasma Plug Flow Reactor Plasma PSR Plug Flow Reactor Premixed Laminar Burner-stabilized Flame Premixed Laminar Flame-speed Calculation SI Engine Zonal Simulator
	Notes	See also QPRO as an alternate way to specify heat-loss as a function of time. Keywords QFUN, QLOS and QPRO are mutually exclusive.
QIAGE Reactor Property/Model	The time delay to turn on the droplet temperature equation at the beginning of liquid vaporization to prevent possible convergence issues at the start of injection. When the Droplet Surface T = Core T option is selected, a very large time delay can force the droplet temperature to be constant, that is, equal to the initial liquid temperature, throughout the simulation.
	Parameters	Optional/Reqd.	Units	Examples
	Time	Required	seconds	QIAGE 1.0E-3
	Keyword Usage	Optional keyword. Default is 0.0 sec.
	Reactor Models	Direct Injection Diesel Engine Simulator
QLOS Reactor Property	The heat loss or heat flux from the reactor to the external environment at an optionally specified surface material. The units are for a total heat loss for 0-D homogeneous reactors, or for heat flux per area for all channel-flow reactors (Plug Flow Reactor, Honeycomb Reactor, Plasma Plug Flow Reactor, and Shear Flow Reactors). This option is only relevant when the energy equation is being solved.
	Parameters	Optional/Reqd.	Units	Examples
	Material name (for 0-D homogeneous and plug-flow reactors only)	Optional If no material is specified, the value will be used for all materials.	--	QLOS material1 50
	Bulk name (multiphase reactors only)	Optional	--	QLOS Gas AMBIENT 0.5
	Heat loss or Heat flux (depending on Reactor Model)	Required	cal/sec or cal/cm2-s	QLOS 50
	Reactor number (PSR clusters only)	Optional If no number is given, the keyword is assumed to apply to all reactors in a cluster.	--	QLOS material1 50 1
	Keyword Usage	Optional keyword. By default, there is no heat loss from the reactor. See also QPRO, HTRN, and QFUN. For the multiphase reactors, the keyword is effective for the phase name following the keyword. The name of the bulk phase should be used. "Gas" indicates the gas phase.
	Reactor Models	Closed Homogeneous Batch Reactor Closed Plasma Reactor Cylindrical Shear Flow Reactor Honeycomb Reactor IC HCCI Engine Non-reactive Gas Mixer Planar Shear Flow Reactor Plasma Plug Flow Reactor Multiphase PSR Plug Flow Reactor Perfectly Stirred Reactor (PSR) SI Engine Zonal Simulator
QLSE Reactor Property Profiles	This is an additional energy loss term for the electrons that may be introduced to account for inelastic collisional losses that are not already included explicitly in the Gas-phase Kinetics reaction mechanism. Energy loss values are specified here as a function of electron temperature and are given per ionization event to be consistent with the work of Lee, et al.[12] For example, "QLSE 34800. 100." would represent an electron energy loss of 100 eV/ionization event for an electron temperature of 34800 K (3.0 eV).
	Parameters	Optional/Reqd.	Units	Examples
	Energy loss	Required	eV	QLSE 34800. 100.
	Electron temperature	Required	K	QLSE 34800. 100.
	Keyword Usage	Optional keyword. By default, the additional energy loss term is 0.0.
	Reactor Models	Closed Plasma Reactor Plasma Plug Flow Reactor Plasma PSR
QPRO Reactor Property Profiles	The heat loss profile or heat flux profile from the reactor to the external environment at an optionally specified surface material, given as a piece-wise linear function of time or distance. Each QPRO entry represents a point in a piecewise-linear profile. The units are for a total heat loss vs. time for 0-D homogeneous reactors, or for heat flux per area vs. distance for all channel-flow reactors (Plug Flow Reactor, Honeycomb Reactor, Plasma Plug Flow Reactor, and Shear Flow Reactors). This option is only relevant when the energy equation is being solved.
	Parameters	Optional/Reqd.	Units	Examples
	Time or Distance value (depending on Reactor Model)	Required	sec or cm	QPRO 1.0E-4 10.0
	Heat loss or Heat flux (depending on Reactor Model)	Required	cal/sec or cal/cm2-sec	QPRO 1.0E-4 10.0
	Reactor number (PSR clusters only)	Optional If no number is given, the profile described by the first two values is assumed to apply to all reactors in a cluster.	--	QPRO 1.0E-4 10.0 1
	Keyword Usage	Optional keyword. By default, there is no heat loss from the reactor. See also QLOS, HTRN, and QFUN.
	Reactor Models	Closed Homogeneous Batch Reactor Closed Plasma Reactor Cylindrical Shear Flow Reactor Honeycomb Reactor IC HCCI Engine Non-reactive Gas Mixer Perfectly Stirred Reactor (PSR) Planar Shear Flow Reactor Plasma PSR Plasma Plug Flow Reactor Multiphase PSR Plug Flow Reactor SI Engine Zonal Simulator
QRGEQ Output	Solve a separate equation that integrates the heat release due to gas-phase reactions to obtain a more accurate heat-release profile. If this option is not checked, only local heat release rates will be reported at each saved or printed time steps. Only applicable when you are solving the energy equation with transient solver.
	Parameters	Optional/Reqd.	Units	Examples
	Keyword Usage	Optional keyword. By default, the heat release integration equation is not solved.
	Reactor Models	Closed Homogeneous Batch Reactor Closed Plasma Reactor Honeycomb Monolith Reactor IC HCCI Engine Perfectly Stirred Reactor (PSR) Plasma PSR Plasma Plug Flow Reactor Plug Flow Reactor SI Engine Zonal Simulator
QRSEQ Output	Solve a separate equation that integrates the heat release due to surface reactions to obtain a more accurate heat-release profile. If this option is not checked, only local heat release rates will be reported at each saved or printed time steps. Only applicable when you are solving the energy equation with transient solver.
	Parameters	Optional/Reqd.	Units	Examples
	Keyword Usage	Optional keyword. By default, the heat release integration equation is not solved.
	Reactor Models	Closed Homogeneous Batch Reactor Closed Plasma Reactor Honeycomb Monolith Reactor IC HCCI Engine Perfectly Stirred Reactor (PSR) Plasma PSR Plasma Plug Flow Reactor Plug Flow Reactor
QXCO Recycling	This keyword defines the heat-transfer coefficient and the heat-transfer surface area for thermal conductive/convective heat flux between the two specified reactors in a reactor cluster. The direction of the heat flux will come from the higher-temperature reactor to the lower-temperature reactor. This keyword is only relevant when the ENRG keyword is used and when there are multiple reactors in a cluster.
	Parameters	Optional/Reqd.	Units	Examples
	Reactor Number	Required	--	QXCO 3 6 1.0E-3 1000.
	Reactor Number	Required	--	QXCO 3 6 1.0E-3 1000.
	Heat-transfer coefficient	Required	cal/(cm² ⋅ sec ⋅ K)	QXCO 3 6 1.0E-3 1000.
	Heat-transfer surface area	Required	cm²	QXCO 3 6 1.0E-3 1000.
	Keyword Usage	Optional keyword. By default, there is no heat exchange between reactors.
	Reactor Models	Perfectly Stirred Reactor (PSR) Plasma PSR
	Notes	The order of the two reactor numbers that define the heat connection is not important. This parameter is used in conjunction with the external surface area (AREAQ or AEXT).
QXRA Recycling	This keyword defines the thermal emissivity/absorptivity and the heat-transfer surface area for thermal radiative flux between the two specified reactors in a reactor cluster. The direction of the heat flux will come from the higher-temperature reactor to the lower-temperature reactor. This keyword is only relevant when the ENRG keyword is used and when there are more than one reactor in a cluster.
	Parameters	Optional/Reqd.	Units	Examples
	Reactor Number	Required	--	QXRA 2 3 0.1 1000.
	Reactor Number	Required	--	QXRA 2 3 0.1 1000.
	Emissivity/absorptivity	Required	--	QXRA 2 3 0.1 1000.
	Heat-transfer surface area	Required	cm²	QXRA 2 3 0.1 1000.
	Keyword Usage	Optional keyword. By default, there is no heat exchange between reactors. Note that the order of the two reactor numbers that define the heat connection is un-important.
	Reactor Models	Perfectly Stirred Reactor (PSR) Plasma PSR
	Notes	The order of the two reactor numbers that define the heat connection is not important. This parameter is used in conjunction with the external surface area (AREAQ or AEXT).
RACTV Reactor Property	By default, when the gas-phase thermal radiation calculation is on, contributions from all major radiating species (such as CO₂, H₂ O, CO, and CH₄) will not be included. A major radiating species is a species of which the absorption coefficient is available to the application. This keyword allows the user to include the contribution of a major species in the radiation heat loss calculation.
	Parameters	Optional/Reqd.	Units	Examples
	Species symbol	Required	--	RACTV CO
	Keyword Usage	Optional keyword.
	Reactor Models	Diffusion or Premixed Opposed-flow Flame Burner-stabilized Pre-mixed Flame Premixed Laminar Flame-speed Calculation
RADB Reactor Property	Use an energy balance to determine the disk or susceptor (deposition surface) temperature. If RADB is specified, TDSK is used as the initial guess for the susceptor temperature.
	Keyword Usage	Optional keyword. By default, the susceptor temperature is fixed as TDSK.
	Reactor Models	Rotating Disk CVD Reactor Stagnation Flow CVD Reactor
RADGS Reactor Property	Turns on the radiation heat loss term in the gas energy equation. The optional model number indicates which thermal radiation model will be employed to calculate the radiation intensity.
	Parameters	Optional/Reqd.	Units	Examples
	Reactor number	Required	--	RADGS 0
	Keyword Usage	Currently, the optically-thin limit model is the only model implemented and hence is the default model. The model number for the optically-thin limit model is 0.
	Reactor Models	Diffusion or Premixed Opposed-flow Flame Burner-stabilized Pre-mixed Flame Premixed Laminar Flame-speed Calculation
RADPT Reactor Property	Allows radiative heat loss contribution from particulates associated with the named material to be included independently.
	Parameters	Optional/Reqd.	Units	Examples
	Material Name	Required	--	RADPT CO
	Reactor Models	Diffusion or Premixed Opposed-flow Flame Burner-stabilized Pre-mixed Flame Premixed Laminar Flame-speed Calculation
RCHG Solver	Maximum relative change in the surface site fractions (over one time step) for which the initial fictitious transient equations that establish the initial surface site fractions can be considered to have converged to steady state.
	Parameters	Optional/Reqd.	Units	Examples
	Maximum relative change	Required	--	RCHG 1.0E-3
	Keyword Usage	Optional keyword. By default, the maximum relative change is set to 1.0E-6.
	Reactor Models	Honeycomb Reactor Plasma Plug Flow Reactor Plug Flow Reactor
RDSK Reactor Property	Ratio of the substrate radius to the separation distance between it and the upper radiating disk. This is used in calculating a surface radiation balance. RRAD is used only if the disk temperature is being calculated by including keyword RADB . See Equation 15–18 of the Chemkin Theory Manual .
	Parameters	Optional/Reqd.	Units	Examples
	Ratio of substrate	Required	--	RDSK 3.0
	Keyword Usage	Optional keyword. This is keyword is required only when RRAD and RADB are included.
	Reactor Models	Rotating Disk CVD Reactor Stagnation Flow CVD Reactor
REAC Inlet or Reactor Property	Mole fraction of the reagent gases entering the reactor for an inlet stream or for the initial conditions in a closed system. For example, REAC fuel1 C2H2 0.5, would indicate that acetylene has a mole fraction of 0.5 in the inlet stream named fuel1. The sum of all the reactant mole fractions should equal to one. However, if they do not the fractions will be normalized so that they do sum to one, and a warning message will be printed to the output file.
	Parameters	Optional/Reqd.	Units	Examples
	Inlet stream name (for PSRs and CVD Reactors only)	Optional If there is no stream name than the reactant and mole fraction apply to all streams.	--	REAC fuel1 C2H2 0.5
	Species name	Required	--	REAC C2H2 0.5
	Reactant fraction	Required	mole fractions	REAC C2H2 0.5
	Keyword Usage	Required keyword, except in cases where an equivalence ratio option is used ( EQUI).
	Reactor Models	Chemical and Phase Equilibrium Calculations Closed Homogeneous Batch Reactor Closed Plasma Reactor Cylindrical Shear Flow Reactor Diffusion or Premixed Opposed-flow Flame Honeycomb Reactor IC HCCI Engine Non-reactive Gas Mixer Partially Stirred Reactor (PaSR) Perfectly Stirred Reactor (PSR) Planar Shear Flow Reactor Plasma Plug Flow Reactor Plasma PSR Multiphase PSR Plug Flow Reactor Premixed Laminar Burner-stabilized Flame Premixed Laminar Flame-speed Calculation Rotating Disk CVD Reactor Stagnation Flow CVD Reactor
	Notes	The REAC keywords must be changed as a set, not individually for a restart run. The REAC keywords must be changed as a set, not individually for continuation run.
RECY Recycling	For a cluster of reactors (NPSR > 1), specifies recycling or routing of a mass flow from one reactor to another and the fractional flow associated with this stream.
	Parameters	Optional/Reqd.	Units	Examples
	Reactor Number, from which the flow originates	Required	--	RECY 2 1 0.3
	Reactor Number, to which the flow is transferred	Required	--	RECY 2 1 0.3
	Percent that will be recycled from Reactor 2 back into Reactor 1	Required	--	RECY 2 1 0.3
	Keyword Usage	Optional keyword. By default all flow out of a reactor in will flow into the next reactor in the series (e.g. RECY 1 2 1.0 and RECY 2 3 1.0 for a three-reactor system). If recycle loops are defined, then the effective "recycling" from the upstream into the downstream reactor will be one minus the sum of the recycle streams out of the upstream reactor into other reactors.
	Reactor Models	Perfectly Stirred Reactor (PSR) Plasma PSR
RELAXC Solver	Controls the convergence method used for transient runs. When applied, it uses a relaxed scheme whereby the integrator solver tries harder to achieve a solution at each time, but occasionally may result in increased time to solve your problem or numerical instabilities. Therefore, you should use this only if your transient run fails with a "nonlinear solver failed to converge repeatedly" message or you believe your problem is very stiff, highly nonlinear or discontinuous.
	Keyword Usage	Optional keyword.
	Reactor Models	Closed Homogeneous Batch Reactor Closed Partially Stirred Reactor Closed Plasma Reactor Cylindrical Shear Flow Reactor Honeycomb Reactor IC HCCI Engine Multi-Zone HCCI Engine Simulator Partially Stirred Reactor (PaSR) Perfectly Stirred Reactor (PSR) Planar Shear Flow Reactor Plasma Plug Flow Reactor Plasma PSR Multiphase PSR Plug Flow Reactor Rotating Disk CVD Reactor SI Engine Zonal Simulator Stagnation Flow CVD Reactor
RELT Solver	This keyword is used to override the default value for the relative perturbation in the solution variable used in the determination of the numerically derived Jacobian.
	Parameters	Optional/Reqd.	Units	Examples
	Relative perturbation	Required	--	RELT 1.E-15
	Keyword Usage	Optional keyword. By default, the relative perturbation is set equal to the square root of the unit round-off error of the machine.
	Reactor Models	Non-reactive Gas Mixer Perfectly Stirred Reactor (PSR) Plasma PSR
REOR Reactor Property	The option may be used when the TRCE option is in effect. Using TRCE, the conservation equation for the last species in the gas-phase and each surface and bulk phase is not solved: the last species concentration (mass fraction or site fraction) is chosen so that the fractions sum to one. The REOR option causes TRCE to choose dynamically and locally (at each mesh point and in each phase) the species of largest concentration and not solve its conservation equation.
	Keyword Usage	Optional keyword. By default, the last species in each phase is chosen.
	Reactor Models	Rotating Disk CVD Reactor Stagnation Flow CVD Reactor
RHO1 Reactor Property	Mass density before the incident shock.
	Parameters	Optional/Reqd.	Units	Examples
	Mass density	Required	gm/cm³	RHO1 1.E-4
	Keyword Usage	Optional keyword. The shock velocity and any two of temperature, pressure, or density must be specified for conditions before the incident shock. See also T1 and P1A .
	Reactor Models	Normal Incident Shock Normal Reflected Shock
RHO2 Reactor Property	Mass density after the incident shock.
	Parameters	Optional/Reqd.	Units	Examples
	Mass density	Required	g/cm³	RHO2 1.E-4
	Keyword Usage	Optional keyword. Any two of temperature, pressure, or density must be specified for conditions after the incident shock. See also T2 and P2A .
	Reactor Models	Normal Incident Shock Normal Reflected Shock
RHO3 Reactor Property	Mass density after the reflected shock.
	Parameters	Optional/Reqd.	Units	Examples
	Mass density	Required	g/cm³	RHO3 1.E-4
	Keyword Usage	Optional keyword. Any two of temperature, pressure, or density must be specified for conditions after the reflected shock. See also T3 and P3A .
	Reactor Models	Normal Reflected Shock
RLGAS Reactor Property	This optional keyword is used to turn the real gas model on or off. Setting the option value to 1 will activate the real gas model if the gas reaction mechanism contains the real gas data. A value of 0 = turn OFF the real gas model and 1= turn ON the model.
	Parameters	Optional/Reqd.	Units	Examples
	Enabled	Required	g/cm³	RLGAS 1
	Keyword Usage	Optional keyword. By default, the real gas model is turned OFF.
	Reactor Models	Closed Homogeneous Batch Reactor Closed Partially Stirred Reactor Cylindrical Shear Flow Reactor Diffusion or Premixed Opposed-flow Flame Flame-Extinction Simulator Honeycomb Reactor IC HCCI Engine Multi-Zone HCCI Engine Simulator Normal Incident Shock Normal Reflected Shock Partially Stirred Reactor (PaSR) Perfectly Stirred Reactor (PSR) Planar Shear Flow Reactor Plug Flow Reactor Rotating Disk CVD Reactor SI Engine Zonal Simulator Stagnation Flow CVD Reactor
RLMIX Reactor Property	This optional keyword will activate the selected real gas mixing rule if the real gas model is turned on (by RLGAS). A value of 0 = use the Van der Waals mixing rule and 1 = use the pseudocritical method (see Real Gas Data).
	Parameters	Optional/Reqd.	Units	Examples
	Method	Required	None	RLMIX 0
	Keyword Usage	Optional keyword. By default, the van der Waals method will be applied.
	Reactor Models	Closed Homogeneous Batch Reactor Closed Partially Stirred Reactor Cylindrical Shear Flow Reactor Diffusion or Premixed Opposed-flow Flame Flame-Extinction Simulator Honeycomb Reactor IC HCCI Engine Multi-Zone HCCI Engine Simulator Normal Incident Shock Normal Reflected Shock Partially Stirred Reactor (PaSR) Perfectly Stirred Reactor (PSR) Planar Shear Flow Reactor Plug Flow Reactor Rotating Disk CVD Reactor SI Engine Zonal Simulator Stagnation Flow CVD Reactor
ROP Output	Inclusion of this keyword causes the rate-of-production coefficients to be printed for specified species. The keyword must be followed by one or more names of species. If any ROP keywords are used, all the rate-of-production coefficients will be computed and written to the XML Solution File (for example, XMLdata.zip). However, only those specified by the ROP keyword will be printed in the diagnostic output file. More than one species may be entered per line. If the line is blank after the ROP keyword, then all rate-of-production contributions are computed and written to the XML Solution File, but none are printed.
	Keyword Usage	Optional keyword. By default, no rate-of-production values are computed.
	Reactor Models	Closed Homogeneous Batch Reactor Closed Plasma Reactor Closed Multiphase Reactor Honeycomb Reactor IC HCCI Engine Perfectly Stirred Reactor (PSR) Plasma Plug Flow Reactor Plasma PSR Multiphase PSR Plug Flow Reactor SI Engine Zonal Simulator
	Notes	This keyword can be added but not removed from a continuation run. Rates of production can be calculated for other Reactor Models through the graphical Ansys Chemkin Post-processor
RPM Reactor Property	Revolutions per minute of the engine crank arm.
	Parameters	Optional/Reqd.	Units	Examples
	Revolutions per minute	Required	rpm	RPM 1200
	Keyword Usage	Optional keyword. By default, the rpm is 1500.
	Reactor Models	IC HCCI Engine SI Engine Zonal Simulator
RRAD Reactor Property	Ratio of the upper radiating disk radius to the separation distance between it and the lower substrate. This is used in calculating a surface radiation balance. RRAD is used only if the disk temperature is being calculated by including keyword RADB . See Equation 15–18 of the Chemkin Theory Manual .
	Parameters	Optional/Reqd.	Units	Examples
	Ratio of the upper radiating disk	Required	--	RRAD 3.0
	Keyword Usage	Required keyword only if RADB and RDSK are included.
	Reactor Models	Rotating Disk CVD Reactor Stagnation Flow CVD Reactor
RSHK Problem Type	Inclusion of this keyword designates a reflected shock problem.
	Keyword Usage	Required keyword. See also ISHK.
	Reactor Models	Normal Reflected Shock
RSTR Cluster Property	Inclusion of this keyword causes Ansys Chemkin to read a solution off the XML Solution File (for example, XMLdata.zip) and begin iteration or integration on the current reactor conditions from this solution.
	Keyword Usage	Optional keyword. By default, a solution is started from the user-specified conditions and no XML Solution File is used.
	Reactor Models	Closed Homogeneous Batch Reactor Closed Partially Stirred Reactor (PaSR) Closed Plasma Reactor Cylindrical Shear Flow Reactor Diffusion or Premixed Opposed-flow Flame Honeycomb Reactor IC HCCI Engine Partially Stirred Reactor (PaSR) Perfectly Stirred Reactor (PSR) Planar Shear Flow Reactor Plasma Plug Flow Reactor Plasma PSR Plug Flow Reactor Premixed Laminar Burner-stabilized Flame Premixed Laminar Flame-speed Calculation Rotating Disk CVD Reactor SI Engine Zonal Simulator Stagnation Flow CVD Reactor
RTIM Solver	Relative tolerance for convergence of Newton iteration as it is used in the pseudo time stepping procedure for steady-state problems employing the Twopnt solver. Since we are not seeking accuracy in a transient solution, this convergence criteria typically does not need to be as stringent as for the Newton iteration on the actual steady-state solution.
	Parameters	Optional/Reqd.	Units	Examples
	Absolute tolerance	Required	--	RTIM 1.E-3
	Keyword Usage	Optional keyword. By default, the relative tolerance is 1.E-4. See also ATIM.
	Reactor Models	Closed Plasma Reactor Cylindrical Shear Flow Reactor Diffusion or Premixed Opposed-flow Flame Honeycomb Reactor Non-reactive Gas Mixer Perfectly Stirred Reactor (PSR) Planar Shear Flow Reactor Plasma PSR Premixed Laminar Burner-stabilized Flame Premixed Laminar Flame-speed Calculation Rotating Disk CVD Reactor Stagnation Flow CVD Reactor
	Notes	For a more precise definition, see the description of RTOL.
RTIME Reactor Property	Turn on or off solution of the residence-time equation for a plug-flow simulation.
	Parameters	Optional/Reqd.	Units	Examples
	String "ON" or "OFF" to toggle the momentum equation	Required	--	RTIME ON RTIME OFF
	Keyword Usage	Optional keyword. By default, the residence-time equation is solved (ON).
	Reactor Models	Honeycomb Reactor Plasma Plug Flow Reactor Plug Flow Reactor
RTLM Solver	A different relative tolerance can be assigned to moment variables in steady-state calculations. By default, the same relative tolerance given by RTOL is used for all variables.
	Parameters	Optional/Reqd.	Units	Examples
	Tolerance	Required	--	RTLM 1.0E-4
	Keyword Usage	Optional keyword. By default, the absolute tolerance is determined by RTOL.
	Reactor Models	Closed Plasma Reactor Cylindrical Shear Flow Reactor Perfectly Stirred Reactor (PSR) Planar Shear Flow Reactor Plasma PSR
RTLS Solver	Relative tolerance used by the transient solver, DASPK, as an indicator of the accuracy desired in the solution for the sensitivity coefficients only. Generally, the sensitivity coefficients need not be solved to a great degree of accuracy, so these tolerances should be lower than the tolerances placed on the physical variables.
	Parameters	Optional/Reqd.	Units	Examples
	Relative tolerance	Required	--	RTLS 1.E-2
	Keyword Usage	Optional keyword. By default, the relative tolerance is 1.E-5.
	Reactor Models	Closed Homogeneous Batch Reactor Closed Multiphase Reactor Closed Plasma Reactor Honeycomb Reactor IC HCCI Engine Perfectly Stirred Reactor (PSR) Plasma PSR Plasma Plug Flow Reactor Multiphase PSR Plug Flow Reactor SI Engine Zonal Simulator
RTOL Solver	Relative tolerance used by the solver to determine convergence and as an indicator of the accuracy desired in the physical solution. In general the value of RTOL roughly corresponds to the number of significant digits that should be expected from a solution. A typical value should be between 10-3 and 10-6, which would provide roughly three to six significant digits.
	Parameters	Optional/Reqd.	Units	Examples
	Relative tolerance	Required	--	RTOL 1.E-3
	Keyword Usage	Optional keyword. The default values are: Open 0-D Reactors run in steady-state mode, Opposed-flow Flame, Premixed Laminar Burner-stabilized Flame, Premixed Laminar Flame-speed Calculation, Shear Flow Reactor: 1.E-4 Normal Incident Shock, Normal Reflected Shock, Plug Flow Reactor, Partially Stirred Reactor (PaSR), CVD: 1.E-6 Closed 0-D Reactors and Open 0-D Reactors run in transient mode: 1.E-8 See also ATOL.
	Reactor Models	Closed Homogeneous Batch Reactor Closed Partially Stirred Reactor (PaSR) Closed Plasma Reactor Cylindrical Shear Flow Reactor Diffusion or Premixed Opposed-flow Flame Honeycomb Reactor IC HCCI Engine Non-reactive Gas Mixer Normal Incident Shock Normal Reflected Shock Opposed-flow Flame Partially Stirred Reactor (PaSR) Perfectly Stirred Reactor (PSR) Planar Shear Flow Reactor Plasma PSR Multiphase PSR Plug Flow Reactor Premixed Laminar Burner-stabilized Flame Premixed Laminar Flame-speed Calculation Rotating Disk CVD Reactor SI Engine Zonal Simulator Stagnation Flow CVD Reactor
SCAT Output	Request the scatter plot of a scalar to be output to the file scatter.plt.
	Parameters	Optional/Reqd.	Units	Examples
	Scalar (temperature or species name)	Required	--	SCAT CH4
	Keyword Usage	Optional keyword. By default, no scatter plot is printed.
	Reactor Models	Closed Partially Stirred Reactor (PaSR) Partially Stirred Reactor (PaSR)
SCCM Inlet Property	The volumetric flow rate into the reactor for an optionally specified inlet stream, in standard cubic centimeters per minute assuming that the inlet temperature is 298.15 K and the inlet pressure is 1 atm unless a different value for TSCCM is provided.
	Parameters	Optional/Reqd.	Units	Examples
	Inlet stream name	Optional If there is no stream name than the volumetric flow rate applies to the default or all defined streams.	--	SCCM secondary_air 300
	Equivalent volumetric flow rate at standard conditions	Required	standard cm³ /min	SCCM secondary_air 300
	Keyword Usage	PSRs and PaSRs: Optional keyword. If none of TAU, FLRT / FPRO, SCCM / SCCMPRO are specified or are nonzero, then a closed-system is assumed. FLRT / FPRO or SCCM / SCCMPRO is required for each INLET stream defined. Stagnation Flow CVD Reactors: FLRT / FPRO or SCCM / SCCMPRO or UINL is required for each inlet stream defined. Rotating Disk CVD Reactors: Optional keyword.
	Reactor Models	Non-reactive Gas Mixer Perfectly Stirred Reactor (PSR) Plasma PSR Rotating Disk CVD Reactor Stagnation Flow CVD Reactor
SCCMPRO Inlet Property Profiles	Used to specify a transient profile or function of mass flow rate vs. time for an inlet stream, in standard cubic centimeters per minute assuming that the inlet temperature is 298.15 K and the inlet pressure is 1 atm unless a different standard temperature ( TSCCM) is entered. The profile specified will be interpolated linearly from the SCCMPRO points provided.
	Parameters	Optional/Reqd.	Units	Examples
	Inlet stream name	Optional If no stream name is given, the profile described by the reactant and mole fraction is assumed to apply to all reactors in a cluster.	--	SCCMPRO purge 0.19 300
	Time	Required	sec (cm for flow reactors)	SCCMPRO 0.19 300
	Equivalent volumetric flow rate at standard conditions	Required	standard cm³ /min	SCCMPRO 0.19 300
	Keyword Usage	PFRs and Monolith Reactors: Flow specification via one of VEL, VDOT, VDOTPRO SCCM SCCMPRO FLRT, or FPRO is required. PSRs and PaSRs: Optional keyword. If none of TAU, FLRT / FPRO, SCCM / SCCMPRO are specified or are nonzero, then a closed-system is assumed. FLRT / FPRO or SCCM / SCCMPRO is required for each INLET stream defined. Stagnation Flow CVD Reactors: FLRT / FPRO or SCCM / SCCMPRO or UINL is required for each inlet stream defined. Rotating Disk CVD Reactors: Optional keyword.
	Reactor Models	Honeycomb Monolith Reactor Non-reactive Gas Mixer Perfectly Stirred Reactor (PSR) Plasma PFR Plasma PSR Plug Flow Reactor Rotating Disk CVD Reactor Stagnation Flow CVD Reactor
SCLM Reactor Property	Scaling factor for the particles moments (moments method) or number density (sectional method). A non-unity value for this parameter changes the units of the (internal) solution variable for particle moments or number density. For example, setting it to 1.0E+06 results in micro-moles whereas setting it to 1.0E+09 means that it is nano-moles. A value of 1 would mean that the unit should be moles. A recommended value for typical problems is 1.0E+12. Such scaling helps preserve the positivity of the solution during numerical computation.
	Parameters	Optional/Reqd.	Units	Examples
	Scaling factor	Required	--	SCLM 1.0E+12
	Keyword Usage	Optional keyword.
	Reactor Models	Closed Homogeneous Batch Reactor Closed Plasma Reactor Flame-Extinction Simulator Honeycomb Monolith Reactor IC HCCI Engine Multi-Zone HCCI Engine Simulator Opposed-flow Flame Perfectly Stirred Reactor (PSR) Plasma Plug Flow Reactor Plasma PSR Plug Flow Reactor Premixed Laminar Burner-stabilized Flame Premixed Laminar Flame-speed Calculation SI Engine Zonal Simulator Stagnation Flow Flame Simulator
SCLS Reactor Property	Scaling factor for the particle surface species concentrations. A non-unity value for this parameter changes the units of the (internal) solution variable for particle surface species. For example, setting it to 1.0E+06 results in micro-moles whereas setting it to 1.0E+09 means that it is nano-moles. A value of 1 would mean that the unit should be moles. A recommended value for typical problems is 1.0E+12. Such scaling helps preserve the positivity of the solution during numerical computation.
	Parameters	Optional/Reqd.	Units	Examples
	Scaling factor	Required	--	SCLS 1.0E+12
	Keyword Usage	Optional keyword.
	Reactor Models	Closed Homogeneous Batch Reactor Closed Plasma Reactor Flame-Extinction Simulator Honeycomb Monolith Reactor IC HCCI Engine Multi-Zone HCCI Engine Simulator Opposed-flow Flame Perfectly Stirred Reactor (PSR) Plasma Plug Flow Reactor Plasma PSR Plug Flow Reactor Premixed Laminar Burner-stabilized Flame Premixed Laminar Flame-speed Calculation SI Engine Zonal Simulator Stagnation Flow Flame Simulator
SCOR Solver	Flag instructing that the transient solver, DASPK will use staggered corrector method to solve sensitivity equations. The staggered corrector method is the sensitivity method that was used in previous versions of Ansys Chemkin and is mainly provided for backwards compatibility. It is generally slower than the default sensitivity method in Chemkin (which is the staggered direct method) but sometimes can be more stable and robust than the staggered direct method.
	Keyword Usage	Optional keyword. By default, DASPK uses staggered corrector method to solve sensitivity equations.
	Reactor Models	Closed Homogeneous Batch Reactor Closed Plasma Reactor Honeycomb Reactor IC HCCI Engine Non-reactive Gas Mixer Perfectly Stirred Reactor (PSR) Plasma PSR Plasma Plug Flow Reactor Plug Flow Reactor SI Engine Zonal Simulator
	Notes	SCOR can be changed for a continuation run, but it cannot be removed from one.
SCOV Output	Analyze the coverage dependence of a surface reaction, that is, create a table of effective reaction rates versus temperature. Surface coverage is assumed to be that of the bath-gas composition. The ALL option is the default and produces tables for every surface reaction. The NONE option suppresses output for all of the reactions. If reaction information is desired for only certain reactions, they may be optionally specified by their number (given in the Pre-processor output) or by typing an exact duplicate of the reaction expression (see example input).
	Parameters	Optional/Reqd.	Units	Examples
	ALL option	Optional, default is ALL	--	SCOV ALL
	NONE option	Optional, default is ALL	--	SCOV NONE
	Surface reaction number list	Optional, default is ALL	--	SCOV 2 5
	Surface reaction expression	Optional, default is ALL	--	SCOV CH(S)+H<=>C(S,R)+H2
	Keyword Usage	Optional keyword. By default, the table output is determined by the ALL or NONE keyword.
	Reactor Models	Mechanism Analyzer
SDOUTPUT_WRITE Output	Write output data to a standard (ascii) print-out file.
	Keyword Usage	Optional keyword. By default, solution data will be written to an ascii output file.
	Reactor Models	All
SENG Output	Inclusion of this keyword causes the calculation of the first-order sensitivity coefficients, with respect to the gas-phase and surface chemistry rate constants, for the growth rate of all bulk phases. Growth-rate sensitivities will be included in the printed output and the XML Solution File (for example, XMLdata.zip).
	Keyword Usage	Optional keyword. By default, no sensitivity coefficients are computed. See also ASEN.
	Reactor Models	Closed Homogeneous Batch Reactor Closed Plasma Reactor Honeycomb Reactor Perfectly Stirred Reactor (PSR) Plasma Plug Flow Reactor Plasma PSR Plug Flow Reactor
	Notes	This keyword can be added but not removed from a continuation run.
SENT Output	Calculate and store sensitivity coefficients for gas temperature with respect to reaction A-factors. See ASEN.
	Keyword Usage	Optional keyword. By default, no sensitivity coefficients are computed or printed. Same as ASEN TEMP.
	Reactor Models	Closed Homogeneous Batch Reactor Closed Plasma Reactor Honeycomb Reactor IC HCCI Engine Multi-Zone HCCI Engine Simulator Perfectly Stirred Reactor (PSR) Plasma Plug Flow Reactor Plasma PSR Plug Flow Reactor Opposed-flow Flame Premixed Laminar Burner-stabilized Flame Premixed Laminar Flame-speed Calculation Rotating Disk CVD Reactor SI Engine Zonal Simulator Stagnation Flow CVD Reactor
SFAC Reactor Property	This keyword specifies that the rates of all surface reactions will be multiplied (scaled) by the factor SFAC. This option is sometimes useful if convergence difficulties are encountered due to unusually large reaction rates. The problem would be first solved with artificially reduced reaction rates, which then can be increased in subsequent continuations or restarts until SFAC is one.
	Parameters	Optional/Reqd.	Units	Examples
	Multiplier value	Required	--	SFAC 2.0
	Reactor number (PSR clusters only)	Optional If no number is given, value is assumed to apply to all reactors in a cluster.	--	SFAC 2.0 1
	Keyword Usage	Optional keyword. By default, the multiplier value is set to 1.0.
	Reactor Models	Closed Homogeneous Batch Reactor Closed Plasma Reactor Cylindrical Shear Flow Reactor Honeycomb Reactor Non-reactive Gas Mixer Perfectly Stirred Reactor (PSR) Planar Shear Flow Reactor Plasma Plug Flow Reactor Plasma PSR Multiphase PSR Plug Flow Reactor Rotating Disk CVD Reactor Stagnation Flow CVD Reactor
SFLR Solver	Sometimes during the solution procedure some of the very small gas-phase mass fractions, surface site fractions, or bulk species fractions may be calculated as a slightly negative number. No solution component will be allowed to drop below the floor value specified by SFLR.
	Parameters	Optional/Reqd.	Units	Examples
	Minimum bounds on the solution variables	Required	--	SFLR -1.E-5
	Keyword Usage	Optional keyword. By default, the minimum bounds on the solution variables is set to -1.E-4
	Reactor Models	Diffusion or Premixed Opposed-flow Flame Non-reactive Gas Mixer Perfectly Stirred Reactor (PSR) Plasma PSR Rotating Disk CVD Reactor Stagnation Flow CVD Reactor Premixed Laminar Burner-stabilized Flame Premixed Laminar Flame-speed Calculation
SFMN Solver	Set the minimum bounds of the surface species concentration to a slightly negative number to allow the solver more room to search for a solution.
	Parameters	Optional/Reqd.	Units	Examples
	Minimum bound	Required	--	SFMN -1.0d-06
	Keyword Usage	Optional keyword. Usable only with Particle Tracking.
	Reactor Models	Opposed-flow Flame Premixed Laminar Burner-stabilized Flame Premixed Laminar Flame-speed Calculation
SGMAXIT Solver	This controls the maximum number of iterations the segregated solver can take per step to solve the problem. The default is 100 and you may increase this value to give the solver greater chance to solve your problem if it is very hard to solve.
	Parameters	Optional/Reqd.	Units	Examples
	Scaling factor	Required	--	SGMAXIT 100
	Keyword Usage	Optional keyword.
	Reactor Models	Diffusion or Premixed Opposed-flow Flame Opposed-flow Flame Premixed Laminar Burner-stabilized Flame Premixed Laminar Flame-speed Calculation
SGTOL Solver	Absolute tolerance criterion on gas-phase mole fractions in segregated scheme.
	Parameters	Optional/Reqd.	Units	Examples
	Absolute tolerance	Required	--	SGTOL 1.0E-10
	Keyword Usage	Optional keyword. The default value is 1E-10.
	Reactor Models	Diffusion or Premixed Opposed-flow Flame Opposed-flow Flame Premixed Laminar Burner-stabilized Flame Premixed Laminar Flame-speed Calculation
SIDR Solver	Turns on the multi-zone SI Engine Zonal simulation with gas-phase chemistry de-activated. The number of zones is set to 2 by default. SIKN and SIDR are mutually exclusive.
	Parameters	Optional/Reqd.	Units	Examples
	Number of zones	Required	--	SIDR 2
	Keyword Usage	Optional keyword.
	Reactor Models	SI Engine Zonal Simulator
SIKN Solver	Turns on the multi-zone SI Engine Zonal simulation with gas-phase chemistry activated. The number of zones is set to 2 by default.SIKN and SIDR are mutually exclusive.
	Parameters	Optional/Reqd.	Units	Examples
	Number of zones	Required	--	SIKN 2
	Keyword Usage	Optional keyword.
	Reactor Models	SI Engine Zonal Simulator
SIOA Reactor Property	Specifies the crank angle when the SI Engine Zonal Simulator properties will be saved to the XML solution file.
	Parameters	Optional/Reqd.	Units	Examples
	crank_angle	Required	degree	SIOA 5.1
	Keyword Usage	Optional keyword.
	Reactor Models	SI Engine Zonal Simulator
SIZE Output	Use this keyword to set the data block size in bytes for the XML Solution File (for example, XMLdata.zip). Changing this value may affect the performance of the XML parsing routines in the graphical Ansys Chemkin Post-processor.
	Parameters	Optional/Reqd.	Units	Examples
	Data block size	Required	bytes	SIZE 10000000
	Keyword Usage	Optional keyword. By default, the data block size is 10 MB.
	Reactor Models	Chemical and Phase Equilibrium Calculations Closed Homogeneous Batch Reactor Closed Partially Stirred Reactor (PaSR) Closed Plasma Reactor Cylindrical Shear Flow Reactor Diffusion or Premixed Opposed-flow Flame Honeycomb Reactor IC HCCI Engine Mechanism Analyzer Non-reactive Gas Mixer Normal Incident Shock Normal Reflected Shock Partially Stirred Reactor (PaSR) Perfectly Stirred Reactor (PSR) Planar Shear Flow Reactor Plasma Plug Flow Reactor Plasma PSR Plug Flow Reactor Premixed Laminar Burner-stabilized Flame Premixed Laminar Flame-speed Calculation Rotating Disk CVD Reactor SI Engine Zonal Simulator Stagnation Flow CVD Reactor
SLIP Reactor Property	Use the slip velocity model to calculate axial velocity at wall when Knudsen number is large. The model calculates the axial velocity at wall as where is the characteristic length, is the axial velocity, is the multiplier, is the tangential momentum accommodation coefficient.
	Parameters	Optional/Reqd.	Units	Examples
	Multiplier	Required	--	SLIP 3.0 0.9
	Tangential momentum accommodation coefficient	Required	--	SLIP 3.0 0.9
	Keyword Usage	Optional keyword. By default, the slip velocity model is not used.
	Reactor Models	Cylindrical Shear Flow Reactor Planar Shear Flow Reactor
SOLUTION _TECHNIQUE Solver	Controls the underlying solution technique. Previous versions of Ansys Chemkin use an older and generally less robust solution method. By default, solution_technique is set to 1, which means the new and generally more robust (and for larger mechanisms often faster) technique is used. Setting solution_technique to 0 uses the older method and you should only use this if you are having convergence issues with Chemkin and are confident you do not have any problems with your mechanism or problem specification.
	Keyword Usage	Optional keyword. By default, SOLUTION_TECHNIQUE is set to 1.
	Reactor Models	Closed Homogeneous Batch Reactor Closed Plasma Reactor Honeycomb Reactor IC HCCI Engine Multi-Zone HCCI Engine Simulator Perfectly Stirred Reactor (PSR) Plasma Plug Flow Reactor Plasma PSR Plug Flow Reactor Opposed-flow Flame Premixed Laminar Burner-stabilized Flame Premixed Laminar Flame-speed Calculation SI Engine Zonal Simulator
SP Problem Type	Constant pressure and entropy constraints.
	Keyword Usage	Optional keyword. Exactly one problem-type keyword must be included.
	Reactor Models	Chemical and Phase Equilibrium Calculations
	Notes	PS keyword.is equivalent.
SPOS Solver	This keyword provides a (small positive) number that will replace any negative species mass or site fractions. The replacement is made after every successful sequence of time steps, upon adding mesh points, and on restart or continuation. SPOS is often helpful in starting difficult problems when the initial guess is far from the solution. SPOS attempts to force the transient solution away from nonphysical regions that may otherwise be entered due to bad initial conditions and badly conditioned systems.
	Parameters	Optional/Reqd.	Units	Examples
	Species mass fraction	Required	--	SPOS 1.E-14
	Keyword Usage	Optional keyword. By default, no substitution is made for negative fractions during solution for all Reactor Models except for Opposed-flow Flames, where the default value is 1.E-10.
	Reactor Models	Diffusion or Premixed Opposed-flow Flame Non-reactive Gas Mixer Perfectly Stirred Reactor (PSR) Plasma PSR Premixed Laminar Burner-stabilized Flame Premixed Laminar Flame-speed Calculation Rotating Disk CVD Reactor Stagnation Flow CVD Reactor
SQRX Solver	A pseudo wall thermal conductivity to allow surface enthalpy production to "overflow" in the downstream direction. This keyword is useful when the reactor model fails to converge repeatedly because of stiff surface chemistry and the reactor wall temperature is not fixed. The overall enthalpy of the reactor is still conserved because this pseudo wall enthalpy flux is included in the energy equation.
	Parameters	Optional/Reqd.	Units	Examples
	Pseudo conductivity	Required	--	SQRX 0.001
	Keyword Usage	Optional keyword. By default, no thermal conduction in wall is considered.
	Reactor Models	Cylindrical Shear Flow Reactor Planar Shear Flow Reactor
SRXN Output	Prints out a table of reaction rates and other pertinent information for a surface reaction. The ALL option is the default and produces tables for every surface reaction. The NONE option suppresses output for all of the reactions. If reaction information is desired for only certain reactions, they may be optionally specified by their number (given in the Pre-processor output) or by typing an exact duplicate of the reaction expression (see example input).
	Parameters	Optional/Reqd.	Units	Examples
	ALL option	Optional, default is ALL	--	SRXN ALL
	NONE option	Optional, default is ALL	--	SRXN NONE
	Surface reaction number list	Optional, default is ALL	--	SRXN 2 5
	Surface reaction expression	Optional, default is ALL	--	SRXN CH(S)+H<=>C(S,R)+H2
	Keyword Usage	Optional keyword. By default, the table output is determined by the ALL or NONE keyword.
	Reactor Models	Mechanism Analyzer
SSDR Reactor Property	The nominal value of the Stoichiometric Scalar Dissipation Rate (SSDR). The first flamelet will be computed for this value.
	Parameters	Optional/Reqd.	Units	Examples
	Nominal value of SSDR	Required	1/s	SSDR 1.0
	Keyword Usage	Optional keyword.
	Reactor Models	Diffusion Flamelet Generator
SSDR_MAX Reactor Property	The maximum value of the Stoichiometric Scalar Dissipation Rate (SSDR). After computing a flamelet for the nominal value (specified by keyword SSDR), continuations to SSDR_MAX are done in a number of steps as specified by keyword NSTEP_HIGH.
	Parameters	Optional/Reqd.	Units	Examples
	Maximum value of SSDR	Optional	1/s	SSDR_MAX 100
	Keyword Usage	Optional keyword.
	Reactor Models	Diffusion Flamelet Generator
SSDR_MIN Reactor Property	The minimum value of the Stoichiometric Scalar Dissipation Rate (SSDR). After computing a flamelet for the nominal value (specified by keyword SSDR), continuations to SSDR_MIN are done in a number of steps as specified by keyword NSTEP_LOW.
	Parameters	Optional/Reqd.	Units	Examples
	Minimum value of SSDR	Optional	1/s	SSDR_MIN 0.001
	Keyword Usage	Optional keyword.
	Reactor Models	Diffusion Flamelet Generator
SSKIP Solver	Skip the initial surface site fraction calculation.
	Keyword Usage	Optional keyword. By default, an initial solution is performed to determine the surface site fractions holding the reagent gas species constant.
	Reactor Models	Honeycomb Monolith Reactor Plasma Plug Flow Reactor Plug Flow Reactor
SSMAXITER Solver	The maximum number of iterations per steady state search, in the steady-state solver TWOPNT. This is the maximum number of iterations that are allowed each time TWOPNT searches to find the steady state solution. Typically you will not need to change this maximum because TWOPNT will revert to its time stepping algorithm and then re-try searching for the steady state.
	Parameters	Optional/Reqd.	Units	Examples
	Maximum steady state iterations	Optional	--	SSMAXITER 120
	Keyword Usage	Optional keyword. By default, the maximum number of iterations is 100.
	Reactor Models	Cylindrical Shear Flow Reactor Diffusion or Premixed Opposed-flow Flame Non-reactive Gas Mixer Perfectly Stirred Reactor (PSR) Planar Shear Flow Reactor Plasma PSR Premixed Laminar Burner-stabilized Flame Premixed Laminar Flame-speed Calculation Rotating Disk CVD Reactor Stagnation Flow CVD Reactor
	Notes	SSMAXITER must be >=1.
SSRX Solver	A pseudo diffusivity for surface species to allow them to diffuse along the wall surface in the downstream direction. This keyword is useful when the reactor model fails to converge repeatedly because of stiff surface chemistry and the reactor wall temperature is fixed. The overall mass and element conservations of the reactor are still satisfied because pseudo surface species fluxes are included in the surface species equations.
	Parameters	Optional/Reqd.	Units	Examples
	Pseudo conductivity	Required	--	SSRX 0.0001
	Keyword Usage	Optional keyword. By default, no surface species flux on wall is considered.
	Reactor Models	Cylindrical Shear Flow Reactor Planar Shear Flow Reactor
	Notes	Typically, the value of SSRX should be kept under 0.01.
SSTT Solver	Inclusion of this keyword indicates that the local sensitivity analysis will be performed instead of the integrated sensitivity analysis for transient or plug-flow calculations. This may be helpful in speeding up calculations of sensitivity, but we caution that the local sensitivity is less accurate than the integrated sensitivity.
	Keyword Usage	Optional keyword. By default, the integrated sensitivity analysis will be performed for transient calculations when sensitivity data is requested.
	Reactor Models	Closed Homogeneous Batch Reactor Closed Plasma Reactor Honeycomb Reactor IC HCCI Engine Perfectly Stirred Reactor (PSR) Plasma PSR Plasma Plug Flow Reactor Plug Flow Reactor SI Engine Zonal Simulator
	Notes	SSTT can be added to a continuation run, but it cannot be removed from one.
STAG Problem Type	Specify a Stagnation Flow CVD Reactor model.
	Keyword Usage	Required keyword. See also OMEG. If the keyword STAG is given and the spin rate OMEG is nonzero, then this inconsistent input will generate an error. A stagnation-point flow can also be specified by using "OMEG 0".
	Reactor Models	Stagnation Flow CVD Reactor
STAGNATION _FLAME Problem Type	Indicates Burner-stabilized Stagnation Flow problem type.
	Keyword Usage	Required keyword.
	Reactor Models	Premixed Laminar Burner-stabilized Stagnation Flow Flame Simulator
STCH Reactor Property	Parameter to produce a non-uniform grid. For cartesian coordinates the initial grid location for a node J is X(J)=A(J-1)STCH, where A=HITE/(NPTS-1)*STCH, HITE is the reactor height, and NPTS is the total number of grid nodes. If STCH=1, a uniform grid is produced. For STCH > 1, the grid is more tightly spaced at the lower boundary (cartesian-coordinates) or at the outer boundary ( cylindrical coordinates), and consequently the grid is more widely spaced at the other boundary.
	Parameters	Optional/Reqd.	Units	Examples
	Cartesian coordinates	Required	--	STCH 1.2
	Keyword Usage	Optional keyword. By default, the program is set to 1.
	Reactor Models	Cylindrical Shear Flow Reactor Planar Shear Flow Reactor
STCK Output	Analyzes the forward and reverse surface reaction’s sticking coefficient, if applicable. The ALL option is the default and produces tables for every surface reaction with a sticking-coefficient formulation. The NONE option suppresses output for all of the reactions. If reaction information is desired for only certain reactions, they may be optionally specified by their number (given in the Pre-processor output) or by typing an exact duplicate of the reaction expression (see example input).
	Parameters	Optional/Reqd.	Units	Examples
	ALL option	Optional, default is ALL	--	STCK ALL
	NONE option	Optional, default is ALL	--	STCK NONE
	Surface reaction number list	Optional, default is ALL	--	STCK 2 5
	Surface reaction expression	Optional, default is ALL	--	STCK CH(S)+H<=>C(S,R)+H2
	Keyword Usage	Optional keyword. By default, the table output is determined by the ALL or NONE keyword.
	Reactor Models	Mechanism Analyzer
STP0 Solver	Initial time step size used by the steady-state solver Twopnt during the initial calculation for the surface conditions at the inlet.
	Parameters	Optional/Reqd.	Units	Examples
	Initial time step	Required	cm	STP0 1.0E-7
	Keyword Usage	Optional keyword. By default, the initial time step is 1.0E-6.
	Reactor Models	Cylindrical Shear Flow Reactor Planar Shear Flow Reactor
STPT Solver	The maximum internal time step for the solver in transient calculations. STPT determines the largest time-step the transient solver can take at one time and thereby controls the resolution for interpolation of specified time-profiles.
	Parameters	Optional/Reqd.	Units	Examples
	Time step	Required	sec	STPT 1.0E-4
	Aurora Usage	Optional keyword. If not specified, then If either DELT or DTSV are specified, STPT is set to the smallest of these values. If neither DELT nor DTSV are specified, then STPT is set to the value of the end time divided by 100.
	Reactor Models	Closed Homogeneous Batch Reactor Closed Plasma Reactor Closed Multiphase Reactor IC HCCI Engine Non-reactive Gas Mixer Perfectly Stirred Reactor (PSR) Plasma PSR Multiphase PSR SI Engine Zonal Simulator
	Notes	See also: DELT and DTSV keywords.
STST Reactor Property	The solution will be obtained using a steady-state calculation (with the solver Twopnt) rather than a transient calculation (using the solver DASPK).
	Keyword Usage	Optional keyword. By default, a steady-state calculation is performed.
	Reactor Models	Non-reactive Gas Mixer Perfectly Stirred Reactor (PSR) Plasma PSR Rotating Disk CVD Reactor Stagnation Flow CVD Reactor
	Notes	Exclusive toggle with TRAN.
SURF Reactor Property	Initial values (transient) or estimates (steady-state) for the surface site fraction values for the surface species on each surface site type (surface phase).
	Parameters	Optional/Reqd.	Units	Examples
	Surface species name	Required	--	SURF Ga(s) 0.001
	Surface fractions	Required	site fractions	SURF Ga(s) 0.001
	Keyword Usage	Optional keyword. By default, the initial or estimated surface-site fractions are 0.0.
	Reactor Models	Closed Homogeneous Batch Reactor Closed Plasma Reactor Cylindrical Shear Flow Reactor Honeycomb Reactor Perfectly Stirred Reactor (PSR) Planar Shear Flow Reactor Plasma Plug Flow Reactor Plasma PSR Plug Flow Reactor Rotating Disk CVD Reactor Stagnation Flow CVD Reactor
	Notes	The sum of the site fractions should equal one for each surface site type (phase). However, if they do not, a cautionary message will be printed and the site fractions for each surface site type will be normalized so the sum does equal one.
SVS0 Reactor Property	Specify the reference gas viscosity at the reference temperature of the Sutherland's-law for viscosity.
	Parameters	Optional/Reqd.	Units	Examples
	Reference gas viscosity at reference temperature	Required.	g/cm-s	SVS0 1.716E-4
	Keyword Usage	Optional.
	Reactor Models	Multi-Zone HCCI Simulator IC HCCI Engine SI Engine Zonal Simulator
SVSS Reactor Property	Specify the Sutherland temperature of the Sutherland's-law for viscosity.
	Parameters	Optional/Reqd.	Units	Examples
	Sutherland temperature	Required.	K	SVSS 114.0
	Keyword Usage	Optional.
	Reactor Models	Multi-Zone HCCI Simulator IC HCCI Engine SI Engine Zonal Simulator
SVST Reactor Property	Specify the reference temperature of the Sutherland's-law for viscosity.
	Parameters	Optional/Reqd.	Units	Examples
	Reference temperature	Required.	K	SVST 273.15
	Keyword Usage	Optional.
	Reactor Models	Multi-Zone HCCI Simulator IC HCCI Engine SI Engine Zonal Simulator
SYMT Reactor Property	Keyword for temperature boundary condition on the upper wall (only used for non-symmetric cartesian coordinates). The upper wall temperature is set equal to the bottom wall temperature if SYMT is specified.
	Keyword Usage	Optional keyword. By default, an adiabatic top wall is used.
	Reactor Models	Planar Shear Flow Reactor