10.4. Alphabetical Listing of Keywords [T-Z]

Table 10.4: Alphabetical Listing of Keywords [T-Z]

Keyword	Definition
T1 Reactor Property	Temperature before the incident shock.
	Parameters	Optional/Reqd.	Units	Examples
	Temperature	Required	K	T1 300.
	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 P1A and RHO1 .
	Reactor Models	Normal Incident Shock Normal Reflected Shock
T2 Reactor Property	Temperature after the incident shock.
	Parameters	Optional/Reqd.	Units	Examples
	Temperature	Required	K	T2 1500.
	Keyword Usage	Optional keyword. Any two of temperature, pressure, or density must be specified for conditions after the incident shock. See also RHO2 and P2A .
	Reactor Models	Normal Incident Shock Normal Reflected Shock
T3 Reactor Property	Temperature after the reflected shock, given as in the equations.
	Parameters	Optional/Reqd.	Units	Examples
	Temperature	Required	K	T2 1500.
	Keyword Usage	Optional keyword. Any two of temperature, pressure, or density must be specified for conditions after the reflected shock. See also RHO3 and P3A .
	Reactor Models	Normal Reflected Shock
TAMB Reactor Property	Ambient temperature for convective or conductive heat transfer out of the system. This keyword is only relevant when the energy equation is being solved.
	Parameters	Optional/Reqd.	Units	Examples
	Material name	Optional. If no material is specified, the same value will be used for all materials.	--	TAMB material1 298
	Ambient temperature	Required	K	TAMB 298
	Reactor number (PSR clusters only)	Optional. If no number is given, the keyword is assumed to apply to all reactors in a cluster.	--	TAMB material1 298 1
	Keyword Usage	Optional keyword. This keyword must be used with HTC .
	Reactor Models	Closed Homogeneous Batch Reactor Closed Plasma Reactor Honeycomb Monolith Reactor Non-reactive Gas Mixer Perfectly Stirred Reactor (PSR) Plasma PSR Plasma Plug Flow Reactor Multiphase PSR Plug Flow Reactor
TAU Reactor Property	The nominal residence time of the gas in the reactor when flow is present.
	Parameters	Optional/Reqd.	Units	Examples
	Nominal residence time	Required	sec	TAU 1.E-3
	Reactor number (PSR clusters only)	Optional If no number is given, the keyword is assumed to apply to all reactors in a cluster.	--	TAU 1.E-3 1
	Keyword usage	PSRs: 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. PaSRs: Optional keyword. Unless the CLSE keyword is used, any two of FLRT, STPT and reactor volume ( VOL) are required.
	Reactor Models	Partially Stirred Reactor (PaSR) Perfectly Stirred Reactor (PSR) Plasma PSR
TBND Solver	The upper boundary for gas temperature. Setting TBND to the upper limit of thermodynamic data can prevent the Gas-phase Kinetics Pre-processor from getting erratic thermal data by extrapolating the fitting polynomials.
	Parameters	Optional/Reqd.	Units	Examples
	Upper boundary	Required	K	TBND 10000.
	Keyword Usage	Optional keyword. By default, the upper boundary is 5000.
	Reactor Models	Closed Homogeneous Batch Reactor Closed Plasma Reactor Diffusion of Premixed Opposed-flow Flame Honeycomb Reactor Perfectly Stirred Reactor (PSR) Plasma Plug Flow Reactor Plasma PSR Plug Flow Reactor Premixed Laminar Burner-stabilized Flame Premixed Laminar Flame-speed Calculation Rotating Disk CVD Reactor Stagnation Flow CVD Reactor
TBTH Reactor Property	Set the bath gas temperature in Kelvin. This temperature is used wherever a single temperature is needed. The default is 298.15 K.
	Parameters	Optional/Reqd.	Units	Examples
	Bath gas temperature	Required	K	TBTH 900.
	Keyword Usage	Optional keyword. By default, the bath gas temperature is 298.15.
	Reactor Models	Mechanism Analyzer
TDIF Reactor Property	Include thermal diffusion (Soret effect) in the transport calculations.
	Keyword Usage	Optional keyword. By default, thermal diffusion is not included.
	Reactor Models	Cylindrical Shear Flow Reactor Diffusion or Premixed Opposed-flow Flame Planar Shear Flow Reactor Premixed Laminar Burner-stabilized Flame Premixed Laminar Flame-speed Calculation Rotating Disk CVD Reactor Stagnation Flow CVD Reactor
TDEL Reactor Property	Set the temperature increment in all tables where the temperature is varied.
	Parameters	Optional/Reqd.	Units	Examples
	Temperature	Required	K	TDEL 200.
	Keyword Usage	Optional keyword. By default, the temperature step is 100 K.
	Reactor Models	Mechanism Analyzer
TDSK Reactor Property	Temperature of the deposition surface. This is a constant value taken as a boundary condition, unless the keyword RADB is given, indicating that the susceptor or disk temperature is calculated from an energy balance. If RADB is specified, TDSK is taken as the initial guess for the susceptor temperature.
	Parameters	Optional/Reqd.	Units	Examples
	Surface temperature	Required	K	TDSK 1200
	Keyword Usage	Required keyword.
	Reactor Models	Rotating Disk CVD Reactor Stagnation Flow CVD Reactor
TEBND Reactor Property	The upper boundary for electron temperature. Can be useful for preventing non-plasma solutions in steady state problems.
	Parameters	Optional/Reqd.	Units	Examples
	Upper boundary	Required	K	TEBND 8000
	Keyword Usage	Optional keyword. By default, the upper boundary is 200000 K (roughly 20 eV).
	Reactor Models	Closed Plasma Reactor Plasma PSR Plasma Plug Flow Reactor
TEIN Inlet Property	Electron temperature in the inlet stream. For most cases, there are no free electrons in the inlet stream, in which case the electron inlet temperature is not used.
	Parameters	Optional/Reqd.	Units	Examples
	Electron temperature	Required	K	TEIN 300.
	Keyword Usage	Optional keyword. By default, the electrons have the same temperature as the inlet gas.
	Reactor Models	Plasma PSR
TEMP Reactor Property	The reactor gas temperature. Depending on the Reactor Model and problem type, this is either the user-supplied temperature constraint ( TGIV), an initial estimate of the temperature ( ENRG), or the initial reactor temperature (for transient cases). See also TPRO.
	Parameters	Optional/Reqd.	Units	Examples
	Reactor gas temperature	Required	K	TEMP 1000.
	Bulk name (multiphase reactors only)	Optional	--	TEMP Gas 300.0
	Reactor number (PSR clusters only)	Optional If no number is given, the keyword is assumed to apply to all reactors in a cluster.	--	TEMP 1000. 1
	Keyword Usage	Required keyword. 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	Chemical and Phase Equilibrium Calculations Closed Homogeneous Batch Reactor Closed Partially Stirred Reactor (PaSR) Closed Plasma Reactor Diffusion or Premixed Opposed-flow Flame Honeycomb Reactor IC HCCI Engine Non-reactive Gas Mixer Partially Stirred Reactor (PaSR) Perfectly Stirred Reactor (PSR) 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 versions, TINI keyword was used for some Reactor Models.
TEST Reactor Property	Specifies an estimate of the equilibrium temperature.
	Parameters	Optional/Reqd.	Units	Examples
	Temperature	Required	K	TEST 2000
	Keyword Usage	Optional keyword. May help convergence to the equilibrium temperature, or assure an appropriate equilibrium temperature is calculated when a second, trivial solution exists (for example, for adiabatic flame-temperature calculations).
	Reactor Models	Chemical and Phase Equilibrium Calculations
TEXP Reactor Property	Specifies the average/cylinder temperature that defines the start of the expansion period. This keyword has a lower priority than QEXP .
	Parameters	Optional/Reqd.	Units	Examples
	temperature	Required	K	TEXP 1150.0
	Keyword Usage	Optional keyword. Default = 1000K.
	Reactor Models	Multi-Zone HCCI Simulator IC HCCI Engine SI Engine Zonal Simulator
TFAL Output	Analyze the fall-off of a gas-phase reaction with respect to changes in the temperature, that is, create a table of reaction rates versus temperature at a constant pressure. The pressure and gas composition are assumed to be that of the bath gas. 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	--	TFAL ALL
	NONE option	Optional, default is ALL	--	TFAL NONE
	Gas reaction number list	Optional, default is ALL	--	TFAL 2 5
	Gas reaction expression	Optional, default is ALL	--	TFAL 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
TFIX Reactor Property	When solving a freely propagating adiabatic flame ( FREE), the problem is posed in a flame-fixed coordinate system. In this case the flame speed becomes an eigenvalue. Therefore, an additional constraint is required. Ansys chooses to supply this additional condition by fixing the temperature at one point in the flame, and this input allows the specification of that fixed temperature. Given the fixed temperature, the flame position is determined from the initial temperature profile as specified by the TPRO or TPROF inputs. If the fixed temperature is not one of the temperatures specified in the input, then a linear interpolation of the temperature profile to determine the position of TFIX is used and a mesh point added at that point.
	Parameters	Optional/Reqd.	Units	Examples
	Temperature	Optional.	K	TFIX 500.
	Keyword Usage	Optional keyword. With TPROF, default is the average of unburned gas temperature (TUNBURNT) and mixture equilibrium temperature. With TPRO, the default is the average of the first and last Temperature profile values.
	Reactor Models	Premixed Laminar Flame-speed Calculation
	Notes	This keyword can be changed for a restart run.
TGIV Problem Type	Do not solve the gas energy equation, but will instead use a fixed user-supplied temperature (see TEMP).
	Parameters	Optional/Reqd.	Units	Examples
	Reactor number (PSR clusters only)	Optional If no number is given, the keyword is assumed to apply to all reactors in a cluster.	--	TGIV 2
	Reactor number (PSR clusters only)	Optional.	--	TGIV catalyst
	Bulk name	Optional	--	TGIV Gas
	Keyword Usage	Optional keyword. Either TGIV or ENRG must be specified, unless CONP, CONV, or COTV problem-types are specified for a closed system. 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 Diffusion or Premixed Opposed-flow Flame Non-reactive Gas Mixer Honeycomb Reactor Perfectly Stirred Reactor (PSR) Plasma Plug Flow Reactor Plasma PSR Multiphase PSR Plug Flow Reactor Premixed Laminar Burner-stabilized Flame Rotating Disk CVD Reactor Stagnation Flow CVD Reactor
	Notes	This keyword can be removed or added for a restart run.
THIG Reactor Property	Set the upper limit of the temperature range (K) in all tables where the temperature is varied. The default is 1500 K.
	Parameters	Optional/Reqd.	Units	Examples
	Temperature	Required	K	THIG 298.15
	Keyword Usage	Optional keyword. By default, the high temperature is 1500.
	Reactor Models	Mechanism Analyzer
THRM Output	Prints out individual thermodynamics tables for the species in the mechanism. The default is ALL, which generates the tables for all species in the mechanism. The GAS, SUR, and BULK options will cause thermodynamic tables for only species in the specified phase to be printed. Listing individual species by their name or by their number (as listed in the Gas-phase Kinetics or Surface Kinetics Pre-processor output files) will generate thermodynamic tables for the specified species. The keyword NONE will suppress all of the species thermodynamic tables.
	Parameters	Optional/Reqd.	Units	Examples
	ALL option	Optional	--	THRM ALL
	NONE option	Optional	--	THRM NONE
	GAS option	Optional	--	THRM GAS
	SUR option	Optional	--	THRM SUR
	BULK option	Optional	--	THRM BULK
	Species name	Optional	--	THRM CH4
	Species number	Optional	--	THRM 3
	Keyword Usage	Optional keyword. By default, the table output is determined by the ALL or NONE keyword.
	Reactor Models	Mechanism Analyzer
TIFP Output	Calculate the ignition delay as the time when the slope of the temperature profile reaches its maximum value. You need to use sufficient number of time points to obtain an accurate temperature profile. Only applicable when you are solving the energy equation with the transient solver.
	Keyword Usage	Optional keyword. See also TLIM and DTIGN .
	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
TIM1 Solver	For the steady-state solver, Twopnt, if the Newton method fails to converge, then the application takes some pseudo time steps in order to bring the current iterate within the domain of convergence of Newton’s method. This input specifies how many time steps to take and the initial size of the time step, for the initial fixed-temperature calculation.
	Parameters	Optional/Reqd.	Units	Examples
	Number of time steps	Required	--	TIM1 50 3.E-7
	Initial size of time step	Required	sec	TIM1 50 3.E-7
	Keyword Usage	Optional keyword. By default, the number of time steps is 100 and the initial size of the time step is 1.E-6. See also TIM2 .
	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
	Notes	In previous versions, TIME keyword was used.
TIM2 Solver	For the steady-state solver, Twopnt, if the Newton method fails to converge, then the application takes some pseudo time steps in order to bring the current iterate within the domain of convergence of Newton’s method. This input specifies how many time steps to take and the initial size of the time step, when the energy equation is being solved.
	Parameters	Optional/Reqd.	Units	Examples
	Number of time steps	Required	--	TIM2 50 3.E-7
	Initial size of time step	Required	sec	TIM2 50 3.E-7
	Keyword Usage	Optional keyword. By default, the number of time steps is 100 and the initial size of the time step is 1.E-6. See also TIM1 .
	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
	Notes	This input is only used when ENRG or ENGE is included.
TIME Solver	The total integration time for the transient simulation. If the job is a continuation run and the keyword CNTT is specified, the final time value will be the starting time plus the value of TIME.
	Parameters	Optional/Reqd.	Units	Examples
	Total integration time	Required	sec	TIME 1.0E-2
	Keyword Usage	Required keyword, except in case of IC HCCI Engine, where NREV can be specified instead.
	Reactor Models	Closed Homogeneous Batch Reactor Closed Partially Stirred Reactor (PaSR) Closed Plasma Reactor IC HCCI Engine Non-reactive Gas Mixer Normal Incident Shock Normal Reflected Shock Partially Stirred Reactor (PaSR) Perfectly Stirred Reactor (PSR) Plasma PSR Multiphase PSR Rotating Disk CVD Reactor SI Engine Zonal Simulator Stagnation Flow CVD Reactor
	Notes	See also CNTT keyword.
TINF Reactor Property	Ambient temperature of the external environment, used for certain heat-transfer options.
	Parameters	Optional/Reqd.	Units	Examples
	ambient temperature	Required	K	TINF 500
	Keyword Usage	Shear Flow Reactors: Optional keyword. Only used if HTRN option is included. By default, the inlet gas temperature is used for the ambient temperature ( TINL). Premixed and Diffusion Flames: Optional keyword. Only used if the user subroutine QFUN is enabled.
	Reactor Models	Cylindrical Shear Flow Reactor Diffusion or Premixed Opposed-flow Flame Planar Shear Flow Reactor Premixed Laminar Burner-stabilized Flame Premixed Laminar Flame-speed Calculation
TINL Inlet Property	The inlet temperature for an inlet stream.
	Parameters	Optional/Reqd.	Units	Examples
	Inlet stream name (for PSRs and CVD Reactors only)	Optional If there is no stream name than the inlet temperature applies to all streams.	--	TINL secondary_air 400
	Inlet temperature	Required	K	TINL 400
	Keyword Usage	Required for each inlet stream when then energy equation will be solved.
	Reactor Models	Cylindrical Shear Flow Reactor Diffusion or Premixed Opposed-flow Flame Non-reactive Gas Mixer Partially Stirred Reactor (PaSR) Perfectly Stirred Reactor (PSR) Planar Shear Flow Reactor Plasma PSR Rotating Disk CVD Reactor Stagnation Flow CVD Reactor
	Notes	In previous versions, TFUE, TOXI, TINF, and GTMP keywords were used.
TINL Reactor Property	The temperature of the stagnation plane.
	Parameters	Optional/Reqd.	Units	Examples
	Stagnation plane name	Optional If there is no stream name than the inlet temperature applies to all streams.	--	TINL StagPlane 600
	Stagnation plane temperature	Required	K	TINL 600
	Keyword Usage	Required for each stagnation plane when then energy equation will be solved.
	Reactor Models	Burner-stabilized Stagnation Flow Reactor
TION Reactor Property	Specified temperature of ions. In this version of the software, there is no separate energy balance that accounts for ion energy gain above the gas temperature. The ions may, however, be much hotter than the neutral species, and this is accounted here as an additional energy loss from the deposited power required to heat the ions to the assumed temperature.
	Parameters	Optional/Reqd.	Units	Examples
	Specified temperature of ions	Required	K	TION 11500.
	Reactor number (PSR clusters only)	Optional If no number is given, the value is assumed to apply to all reactors in a cluster.	--	TION 11500. 1
	Keyword Usage	Optional keyword. By default, the ions have the same temperature as the neutral gas.
	Reactor Models	Closed Plasma Reactor Plasma Plug Flow Reactor Plasma PSR
TJAC Solver	For the steady-state solver Twopnt, specifies the maximum number of Newton steps that can be taken in performing the pseudo time-stepping before a new Jacobian is evaluated. If TJAC=1, then a full Newton method will result.
	Parameters	Optional/Reqd.	Units	Examples
	Retirement age	Required	--	TJAC 15
	Keyword Usage	Optional keyword. By default, the retirement age is set at 20.
	Reactor Models	Cylindrical Shear Flow Reactor Diffusion or Premixed Opposed-flow Flame Non-reactive Gas Mixer Perfectly Stirred Reactor (PSR) Plasma PSR Planar Shear Flow Reactor Premixed Laminar Burner-stabilized Flame Premixed Laminar Flame-speed Calculation Rotating Disk CVD Reactor Stagnation Flow CVD Reactor
TLIM Output	For all transient problems in which the temperature is allowed to vary, an "ignition time" is computed, which is defined as the time or distance when the temperature first reaches a value equal to TLIM.
	Parameters	Optional/Reqd.	Units	Examples
	Ignition temperature	Required	K	TLIM 500
	Keyword Usage	Optional keyword. See also DTIGN .
	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
TLOW Reactor Property	Set the lower limit of the temperature range (K) in all tables where the temperature is varied. The default is 300 K.
	Parameters	Optional/Reqd.	Units	Examples
	Temperature	Required	K	TLOW 100.
	Keyword Usage	Optional keyword. By default, the low temperature is 300 K.
	Reactor Models	Mechanism Analyzer
TMAX Reactor Property	Maximum temperature for use with profiles defined by the LINE or PLAT options.
	Parameters	Optional/Reqd.	Units	Examples
	Maximum temperature	Required	K	TMAX 2500.
	Keyword Usage	Optional keyword. By default, the maximum temperature is set at 2200 K.
	Reactor Models	Diffusion or Premixed Opposed-flow Flame
TOFF Reactor Property	This keyword is used to tell the Twopnt solver to ignore the temperature when adapting the grid. This can be useful for strained flames, since the temperature gradients can be very steep and, without this option, too many points will be placed in the same place without improving the solution. The flame can be well resolved by basing adaptation only on the species and velocity profiles.
	Keyword Usage	Optional keyword. By default, the temperature is considered during adaptation.
	Reactor Models	Rotating Disk CVD Reactor Stagnation Flow CVD Reactor
TP Problem Type	Constant pressure and temperature constraint.
	Keyword Usage	Optional keyword. Exactly one problem-type keyword must be included.
	Reactor Models	Chemical and Phase Equilibrium Calculations
	Notes	PT keyword is equivalent.
TPRO Reactor Property Profiles	Reactor gas temperature profile specified as a function of time for transient 0-D homogeneous systems or as a function of distance for channel-flow reactors or reactors where there is a constrained temperature. For 1-D steady-state Reactor Models where the energy equation is being solved, TPRO is used to specify an initial temperature profile estimate.
	Parameters	Optional/Reqd.	Units	Examples
	Time or Distance value, depending on Reactor Model	Required	sec or cm	TPRO 1.0E-4 1000
	Gas Temperature	Required	K	TPRO 1.0E-4 1000
	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.	--	TPRO 1.0E-4 1000 1
	Keyword Usage	Optional keyword. By default, no profile is provided.
	Reactor Models	Closed Homogeneous Batch Reactor 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 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
TPROF Reactor Property	Reactor gas temperature profile estimated as a function of distance for flame speed simulator and pre-mixed burner simulator with the energy equation being solved. It uses unburned gas temperature and mixture equilibrium temperature as corresponding upper and lower bounds. When TPROF is used, user-specified values of estimated center position (XCEN), estimated zone width (WMIX), and optional temperature constraint (TFIX) are ignored and pre-defined values are used. When TPROF is used with no NPTS, a default non-linear12-point grid is initialized, while TPROF with NPTS initializes a linear NPTS-point grid.
	Keyword Usage	Optional keyword.
	Reactor Models	Premixed Laminar Burner-stabilized Flame Premixed Laminar Flame-speed Calculation
TPROFILE_n Reactor Property	Choice for the initial temperature profile. Integer n can be 1 or 2. Option 1 means a dumped energy profile (that is, all internal grid-points at specified maximum temperature) and option 2 means a linear profile from the boundary to grid-point where mixture fraction value is stoichiometric.
	Keyword Usage	Required keyword. The default value is TPROFILE_1.
	Reactor Models	Diffusion Flamelet Generator
TRAD Reactor Property	Temperature of a radiating disk located above and parallel to the substrate, used in calculating a surface radiation balance. A hot radiating disk may be included in addition to a cool "wall" ( TWAL), to represent, for example, a burner inlet. The geometry and location of the radiating disk are controlled by keywords RDSK and RRAD. TRAD 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
	Temperature of a radiating disk	Required	K	TRAD 2500.
	Keyword Usage	Optional keyword. By default, the temperature of a radiating disk is 1000 K.
	Reactor Models	Rotating Disk CVD Reactor Stagnation Flow CVD Reactor
TRAN Solver	Perform a transient calculation instead of a steady-state calculation. Forflame simulators, this input also specifies how many time steps to take and the initial size of the time step. Perform a transient calculation (with the solver DASPK) instead of a steady-state calculation (using the solver Twopnt).
	Keyword Usage	Required keyword for Closed Homogeneous Batch Reactor, Closed Plasma Reactor, and the IC HCCI Engine. Otherwise, a steady-state calculation is performed by default.
	Reactor Models	Closed Homogeneous Batch Reactor Closed Plasma Reactor IC HCCI Engine Non-reactive Gas Mixer Perfectly Stirred Reactor (PSR) Plasma PSR Rotating Disk CVD Reactor Stagnation Flow CVD Reactor Diffusion or Premixed Opposed-flow Flame Premixed Laminar Burner-stabilized Flame Premixed Laminar Flame-speed Calculation SI Engine Zonal Simulator
	Notes	See also STST.
TRAN Output	Prints out the transport database properties (intermolecular potential parameters) for each gas-phase species in the mechanism. This feature also expands the thermo table to create a table of transport properties as a function of temperature. The NONE option turns off printing of this table. The Transport Pre-processor must have been run successfully, unless the NONE option is used.
	Parameters	Optional/Reqd.	Units	Examples
	ALL option	Optional	--	TRAN ALL
	NONE option	Optional	--	TRAN NONE
	Keyword Usage	Optional keyword. By default, the table output is determined by the ALL or NONE keyword.
	Reactor Models	Mechanism Analyzer
TRCE Reactor Property	Including this keyword causes the calculation to be run by setting the mass fraction of the last-named Gas-phase Kinetics gas-phase species (or when REOR is used, the species with the largest concentration) to be one minus the sum of the mass fractions of the other species. A conservation equation is not solved for the last (or largest-concentration) species.
	Keyword Usage	Optional keyword. By default, correction velocity formalism is used.
	Reactor Models	Premixed Laminar Burner-stabilized Flame Premixed Laminar Flame-speed Calculation Rotating Disk CVD Reactor Stagnation Flow CVD Reactor
	Notes	This keyword can be removed or added for a restart run.
TRES Restart	Assigns a new initial time for a calculation that starts using the solution read from an XML Solution File.
	Parameters	Optional/Reqd.	Units	Examples
	Initial time	Required	sec	TRES 0.0
	Keyword Usage	Optional keyword. By default, the value of time found on the XML Solution File will be used.
	Reactor Models	Closed Homogeneous Batch Reactor Closed Partially Stirred Reactor (PaSR) Closed Plasma Reactor IC HCCI Engine Partially Stirred Reactor (PaSR) Perfectly Stirred Reactor (PSR) Plasma PSR SI Engine Zonal Simulator
TRMAXITER Solver	The maximum number of iterations time step in TWOPNT's time stepping algorithm. If TWOPNT exceeds this maximum, then it will cut its time step and try again. You may occasionally need to use this option is the time stepping algorithm is having difficulty solving your problem.
	Parameters	Optional/Reqd.	Units	Examples
	Maximum iterations per time step	Optional	--	TRMAXITER 50
	Keyword Usage	Optional keyword. By default, the maximum number of iterations is 25.
	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	TRMAXITER must be >=1.
TRST Restart	Tells the application which time value in an XML Solution File to use for the initial conditions of the current calculation.
	Parameters	Optional/Reqd.	Units	Examples
	Time value	Required	sec	TRST 1.0E-5
	Keyword Usage	Optional keyword. By default, the last time value found on the XML Solution File will be used.
	Reactor Models	Closed Homogeneous Batch Reactor Closed Plasma Reactor Honeycomb Reactor IC HCCI Engine Perfectly Stirred Reactor (PSR) Plasma Plug Flow Reactor Plasma PSR Plug Flow Reactor SI Engine Zonal Simulator
TS Problem Type	Constant entropy and temperature constraints.
	Keyword Usage	Optional keyword. Exactly one problem-type keyword must be included.
	Reactor Models	Chemical and Phase Equilibrium Calculations
	Notes	ST keyword is equivalent.
TSCCM Inlet Property	Sets the standard reference temperature used to define the flow rate when it is input in standard cubic centimeters per minute (sccm), that is, when SCCM or SCCMPRO keywords are used.
	Parameters	Optional/Reqd.	Units	Examples
	Standard temperature	Required	K	TSCCM 300
	Keyword Usage	Optional keyword. By default, the reference temperature is set to 298.15 K.
	Reactor Models	Non-reactive Gas Mixer Perfectly Stirred Reactor (PSR) Plasma PSR Rotating Disk CVD Reactor Stagnation Flow CVD Reactor
TSFAC Reactor Property/Model	The maximum liquid/droplet temperature allowed to prevent issues from liquid property evaluation. This maximum temperature value is specified as a fraction of the lowest critical temperature of the liquid component.
	Parameters	Optional/Reqd.	Units	Examples
	Temperature change	Required	K	TSFAC 5.0
	Keyword Usage	Optional keyword. Default is 1 K.
	Reactor Models	Direct Injection Diesel Engine Simulator
TSPL Reactor Property Profiles	This keyword allows an optional specification of a spline-fit surface temperature profile of the lower wall for planar non-symmetric cases or otherwise the surface temperature profile of the upper wall. The data point describing the surface temperature profile is formatted as an pair. There is a TSPL keyword line for each desired pair. The coordinates of each TSPL line must be given in ascending order. A spline fit is used to interpolate between points.
	Parameters	Optional/Reqd.	Units	Examples
	coordinate	Required	cm	TSPL 0.1 973
	coordinate	Required	K	TSPL 0.1 973
	Keyword Usage	Optional keyword. By default, for symmetric cases default is specified constant temperature; for non-symmetric cases the wall is adiabatic.
	Reactor Models	Cylindrical Shear Flow Reactor Planar Shear Flow Reactor
	Notes	See also: TPRO.
TSRF Reactor Property	The temperature of the surfaces in the reactor. Use only if you want the surface temperature, which controls the surface chemistry rates, to be different than the gas temperature.
	Parameters	Optional/Reqd.	Units	Examples
	Material (for 0-D homogeneous and plug-flow reactors only)	Optional If not specified, then the temperature is the same for all materials.	--	TSRF WAFER 1200.
	Surface temperature	Required	K	TSRF 1200.
	Reactor number (PSR clusters only)	Optional If no number is given, the value is assumed to apply to all reactors in a cluster.	--	TSRF 1200. 1
	Keyword Usage	Closed Homogeneous, PSRs, and Plug Flow Reactors: Optional keyword. If not specified, the surface temperature is assumed to be the same as the gas temperature. Shear Flow Reactors: Required keyword.
	Reactor Models	Closed Homogeneous Batch Reactor Closed Plasma Reactor Cylindrical Shear Flow Reactor Diffusion or Premixed Opposed-flow Flame Honeycomb Reactor Perfectly Stirred Reactor (PSR) Planar Shear Flow Reactor Plasma Plug Flow Reactor Plasma PSR Plug Flow Reactor
	Notes	In previous versions, STMP keyword was used.
TSTAU Reactor Property/Model	An artificial damping factor to control how the droplet temperature approaches the maximum temperature value. A large damping factor will result in a smooth droplet temperature profile as it rises towards the maximum value. The damping factor value must be greater than 1K.
	Parameters	Optional/Reqd.	Units	Examples
	Temperature change	Required	K	TSTAU 5.0
	Keyword Usage	Optional keyword. Default is 1 K.
	Reactor Models	Direct Injection Diesel Engine Simulator
TSTP Solver	Initial time step used for integration of the fictitious transient equations used to determine an initial set of surface site fractions for the plug-flow simulation. Steady-state is assumed to be reached when there is no significant change in the surface site fractions over the course of one time step (see RCHG ).
	Parameters	Optional/Reqd.	Units	Examples
	Initial time step	Required	cm	TSTP 0.1
	Keyword Usage	Optional keyword. By default, the initial time step is 1.
	Reactor Models	Honeycomb Reactor Plasma Plug Flow Reactor Plug Flow Reactor
TSTR Cluster Property	This keyword is valid when using the XMLI, XMLS or RSTR option, when the XML Solution File used for initialization or restart contains transient data. In this case, select the values to use in initialization or restart as those corresponding to the time that is closest to (greater than or equal to) the specified time.
	Parameters	Optional/Reqd.	Units	Examples
	Time	Required	sec	TSTR 0.01
	Keyword Usage	Optional keyword. By default, uses the data from the last time-step found in the XML Solution File.
	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 Mechanism Analyzer Non-reactive Gas Mixer Normal Incident Shock Normal Reflected Shock 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
TSTR Solver	Starting time for the simulation.
	Parameters	Optional/Reqd.	Units	Examples
	Time	Required	sec	TSTR 0.01
	Keyword Usage	Optional keyword. By default, the starting time is 0.0
	Reactor Models	Normal Incident Shock Normal Reflected Shock
TSUM Output	Controls the printing of summary tables for the thermodynamic functions at the bath gas conditions (see TBTH, PRES, and XBTH). There are three sets of thermodynamic tables: one for the species, one for the gas reactions, and one for the surface reactions. The last three options turn on each table individually. The default is ALL, which will print all three thermodynamic tables. They may all be suppressed with NONE.
	Parameters	Optional/Reqd.	Units	Examples
	ALL option	Optional	--	TSUM ALL
	NONE option	Optional	--	TSUM NONE
	SPECIES option	Optional	--	TSUM SPECIES
	GAS option	Optional	--	TSUM GAS
	SUR option	Optional	--	TSUM SUR
	Keyword Usage	Optional keyword. By default, the table output is determined by the ALL or NONE keyword.
	Reactor Models	Mechanism Analyzer
TSWH Reactor Property	Defines when the calculation will be switched from TGIV to ENRG with Woschni correlation as the heat transfer model. The default value is 0 sec (always use energy equation).
	Parameters	Optional/Reqd.	Units	Examples
	Time in seconds	Required	sec	TSWH 0.001
	Keyword Usage	Optional keyword.
	Reactor Models	Multi-Zone HCCI Engine Simulation
TTIM Reactor Property	The solution will be obtained with pressure and temperature given as specified functions of time through a user-programmed subroutine. The SUBROUTINE PSTEMPT (TIME, LOUT, TEMP, PA) must be provided to specify the temperature and linked to the application program. See the Application Programming Interface Manual for information on how to work with user subroutines.
	Keyword Usage	Optional keyword. By default, temperature and pressure will be specified by keyword. See also TPRO and PPRO.
	Reactor Models	Closed Homogeneous Batch Reactor Closed Plasma Reactor IC HCCI Engine Non-reactive Gas Mixer Perfectly Stirred Reactor (PSR) Plasma PSR SI Engine Zonal Simulator
	Notes	See also TPRO and PPRO as alternative ways to specify temperature and pressure as functions of time.
TUNBURNT Reactor Property	Unburned gas temperature.
	Parameters	Optional/Reqd.	Units	Examples
	Unburned gas temperature	Required	K	TUNBURNT 300.0
	Keyword Usage	Required keyword.
	Reactor Models	Premixed Laminar Burner-stabilized Flame Premixed Laminar Flame-speed Calculation
TV Problem Type	Constant volume and temperature constraints.
	Keyword Usage	Optional keyword. Exactly one problem-type keyword must be included.
	Reactor Models	Chemical and Phase Equilibrium Calculations
	Notes	VT keyword is equivalent.
TWAB Solver	Absolute error tolerance used by the steady-state Twopnt solver in the initial calculation at the inlet boundary.
	Parameters	Optional/Reqd.	Units	Examples
	Absolute error tolerance	Required	--	TWAB 1.0E-5
	Keyword Usage	Optional keyword. By default, the absolute error tolerance is 1.0E-13.
	Reactor Models	Cylindrical Shear Flow Reactor Planar Shear Flow Reactor
TWAL Reactor Property	Temperature of a neighboring "wall" used in calculating a surface radiation balance. This value 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
	Wall temperature	Required	K	TWAL 850.0
	Keyword Usage	Optional keyword. By default, the wall temperature is 500 K.
	Reactor Models	Rotating Disk CVD Reactor Stagnation Flow CVD Reactor
TWPR Output	Specifies print level for the initial steady-state solution of the inlet boundary by the Twopnt solver.
	Parameters	Optional/Reqd.	Units	Examples
	Print level	Required	--	TWPR 0
	Keyword Usage	Optional keyword. By default, the print level is set at 22.
	Reactor Models	Cylindrical Shear Flow Reactor Planar Shear Flow Reactor
TWRE Solver	Relative error tolerance used by the steady-state Twopnt solver in the initial calculation at the inlet boundary.
	Parameters	Optional/Reqd.	Units	Examples
	Relative error tolerance	Required	--	TWRE 1.0E-10
	Keyword Usage	Optional keyword. By default, the relative error tolerance is 1.0E-4.
	Reactor Models	Cylindrical Shear Flow Reactor Planar Shear Flow Reactor
TWST Solver	Number of time steps before trying another Newton step, used by the steady-state Twopnt solver in the initial calculation at the inlet boundary.
	Parameters	Optional/Reqd.	Units	Examples
	Number of time steps	Required	--	TWST 50
	Keyword Usage	Optional keyword. By default, the number of time steps is set at 100.
	Reactor Models	Cylindrical Shear Flow Reactor Planar Shear Flow Reactor
UFAC Solver	Factor by which to multiply the time step in the steady-state Twopnt ’s pseudo time stepping procedure when the number of time steps at the current step size reaches the number specified by IRET.
	Parameters	Optional/Reqd.	Units	Examples
	Multiply factor	Required	--	UFAC 2.2
	Keyword Usage	Optional keyword. By default, the multiplication factor is set to 2.0.
	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
UIGN Output, User Subroutine	Use the ignition delay time definition given in the user routine `PSIGNT`. Only applicable when you are solving the energy equation with transient solver. See the Application Programming Interface Manual for details on how to work with user subroutines.
	Parameters	Optional/Reqd.	Units	Examples
	Keyword Usage	Optional keyword.
	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
UINL Reactor Property	The axial velocity at the inlet boundary. If the rotations rate OMEG is zero, or if the STAG option is used, then UINL is no longer optional, but must be given to specify the problem.
	Parameters	Optional/Reqd.	Units	Examples
	Axial inlet velocity	Required	cm/sec	UINL 23.6
	Keyword Usage	Diffusion or Premixed Opposed-flow Flames: Required keyword for each inlet stream. Rotating Disk CVD Reactor: Optional keyword. The velocity at the outer domain is calculated as a part of the solution. However, using the keyword UINL, one may impose this velocity upon the solution. By default, the axial inlet velocity is 0. Stagnation Flow CVD Reactor: Required keyword.
	Reactor Models	Diffusion or Premixed Opposed-flow Flame Rotating Disk CVD Reactor Stagnation Flow CVD Reactor
	Notes	In previous versions: UINF, VFUE, or VOXI keywords were used.
UPROF Reactor Property, User Subroutine	Reactor inlet profiles will be given by a user-programmed subroutine. SUBROUTINE CRUPROF must be provided to specify the inlet profiles of all variables 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, a uniform inlet profile is used for all variables except axial velocity. The axial velocity profile is uniform in the Planar Shear Flow Reactor model and is parabolic (or fully developed) in the Cylindrical Shear Flow Reactor model.
	Reactor Models	Cylindrical Shear Flow Reactor Planar Shear Flow Reactor
UREF Reactor Property	For the IC HCCI Engine ( ICEN), the heat transfer model ( ICHT) evaluates viscosity and thermal conductivity using the instantaneous temperature and pressure inside the cylinder. The UREF keyword is a flag that instructs the heat transfer model to use transport properties evaluated at the initial condition instead. UREF is turned off by default therefore it must be added to old input files in which keyword ICHT is used to reproduce the old results.
	Keyword Usage	Optional keyword. By default, properties are evaluated using local conditions.
	Reactor Models	IC HCCI Engine SI Engine Zonal Simulator
USE _TPRO_GRID Reactor Property	Uses an initial non-uniform grid based on points specified in the estimated temperature profile (TPRO or TPROF).
	Keyword Usage	Optional keyword.
	Reactor Models	Premixed Laminar Burner-Stabilized Flame Premixed Laminar Flame-Speed Calculation
USE_TEMPERATURE Reactor Property	Use the temperature of another bulk for this phase.
	Parameters	Optional/Reqd.	Units	Examples
	Use same temperature as another phase	Optional	--	USE_TEMPERATURE jetFuel Gas
	Keyword Usage	This keyword indicates that the first phase following the keyword use the same temperature as that of the last phase specified.
	Reactor Models	Closed Multiphase Reactor Multiphase PSR
USEP Cluster Property	For use with XMLI, XMLS, or RSTR, to override the values of pressure found on the XML Solution File used for restart or initialization with those specified in the user input file.
	Keyword Usage	Optional keyword. By default, the program uses the pressure from the XML Solution File.
	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 Mechanism Analyzer Non-reactive Gas Mixer Normal Incident Shock Normal Reflected Shock 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 Stagnation Flow CVD Reactor
USET Cluster Property	For use with XMLI, XMLS, or RSTR, override the values of temperature found on the XML Solution File used for restart or initialization with those specified in the user input file.
	Keyword Usage	Optional keyword. By default, the program uses the temperature from the XML Solution File.
	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 Mechanism Analyzer Non-reactive Gas Mixer Normal Incident Shock Normal Reflected Shock 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
	Notes	In previous versions, USTG keyword was used.
USEV Restart	This keyword is valid when using XMLI or the RSTR options. When this keyword is included, it overrides the values of velocity or flow-rate found on the XML Solution File used for restart or initialization with those specified in the user input file.
	Keyword Usage	Optional keyword. By default, the program uses the velocity or flow-rate from the XML Solution File.
	Reactor Models	Honeycomb Reactor Perfectly Stirred Reactor (PSR) Plasma Plug Flow Reactor Plasma PSR Plug Flow Reactor Premixed Laminar Burner-stabilized Flame Premixed Laminar Flame-speed Calculation Rotating Disk CVD Reactor Stagnation Flow CVD Reactor
USEV XMLI	When using XMLI, XMLS, or RSTR, overrides the values of velocity or flow-rate found on the XML Solution File used for restart or initialization with those specified in the user input file.
	Keyword Usage	Optional keyword. By default, the program uses the velocity or flow-rate from the XML Solution File.
	Reactor Models	Cylindrical Shear Flow Reactor Honeycomb Reactor 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 Stagnation Flow CVD Reactor
USRIN Inlet Property	Specification of a reactor inlet stream using a user-programmed subroutine. Use of USRIN requires that a user routine SUBROUTINEUSRINLET (LIUIN, IINWRK, LRUIN, RINWRK, INAME, KNAMES, FLRT, TINL, TEIN, XIN) is written and linked to the application program. Calls to this routine will be used to obtain the corresponding flow rate ( FLRT), inlet temperature ( TINL), engine-out electron temperature ( TEIN), and composition ( REAC). See the Application Programming Interface Manual for more information on how to work with user subroutines.
	Parameters	Optional/Reqd.	Units	Examples
	Stream	Required	--	USRIN engineout 2
	Reactor number (PSR clusters only)	Optional, if not defined, then reactor #1 is assumed.	--	USRIN engineout 2
	Keyword Usage	Optional keyword. By default, streams are defined using the INLET and related keyword.
	Reactor Models	Non-reactive Gas Mixer Perfectly Stirred Reactor (PSR) Plasma PSR
	Notes	See User Supplemental Programming of the Application Programming Interface Manual for details.
UTRN Reactor Property, User Subroutine	Use the mixture average transport properties defined in user-programmed routine `CRUTRANS` (for Shear Flow reactors), `OPUTRANS` (for Opposed-flow Flame Simulator) or `PRUTRANS` (for Premixed Laminar Flame or Flame-speed Calculation). See the Application Programming Interface Manual for details on how to work with user subroutines.
	Keyword Usage	Optional keyword. By default, transport properties will be calculated based on the fundamental transport properties provided in the chemistry set.
	Reactor Models	Cylindrical Shear Flow Reactor Opposed-flow Flame Simulator Planar Shear Flow Reactor Premixed Laminar Burner-stabilized Flame Premixed Laminar Flame-speed Calculation
UWGT Reactor Property	Grid refinement weighting factor for the axial velocity. A value greater than 1 will increase the grid resolution outside of the reacting zone/wall region to improve the accuracy of velocity solutions near the inlet region.
	Parameters	Optional/Reqd.	Units	Examples
	Weighting Factor	Optional	--	UWGT 2.0
	Keyword Usage	Optional keyword. Default value is 1.
	Reactor Models	Rotating Disk CVD Reactor Stagnation Flow CVD Reactor
VCPRO Reactor Property	The cylinder volume is given by a series of CA-volume data points prepended by the keyword VCPRO. The CA data values must be monotonically ascending and must span from the starting crank angle to the ending crank angle. The volume data must be positive.
	Parameters	Optional/Reqd.	Units	Examples
	CA	Required	degree	VCPRO -165.0 35.14
	Volume	Required	cm³	VCPRO -165.0 35.14
	Keyword Usage	Optional keyword (required to turn ON this option).
	Reactor Models	Direct Injection Diesel Engine Simulator IC HCCI Engine Multi-Zone HCCI Engine SI Engine Zonal Simulator
VCOR Reactor Property	Including this keyword causes the calculation to be run using a correction velocity to ensure mass conservation, that is, the sum of the diffusion fluxes is zero. See Equation 15–11 of the Chemkin Theory Manual . If VCOR is not used, then TRCE is in effect.
	Keyword Usage	Optional keyword. By default, correction velocity is not used.
	Reactor Models	Cylindrical Shear Flow Reactor Planar Shear Flow Reactor Premixed Laminar Burner-stabilized Flame Premixed Laminar Flame-speed Calculation Rotating Disk CVD Reactor Stagnation Flow CVD Reactor
VDOT Inlet Property	Inlet volumetric flow rate.
	Parameters	Optional/Reqd.	Units	Examples
	Inlet volumetric flow rate	Required	cm³ /sec	VDOT 100
	Keyword Usage	Optional keyword. Either VDOT or VEL must be specified, unless this is a restart run. PFRs and Monolith Reactors: Flow specification via one of VEL, VDOT, VDOTPRO SCCM SCCMPRO FLRT, or FPRO is required.
	Reactor Models	Honeycomb Reactor Plasma Plug Flow Reactor Multiphase PSR Plug Flow Reactor
VDOTPRO Inlet PropertyProfiles	Specifies a transient profile or function of mass flow rate vs. independent variable (time or position) for an inlet stream, in cubic centimeters per minute. The profile specified will be interpolated linearly from the `VDOTPRO` points provided.
	Parameters	Optional/Reqd.	Units	Examples
	Inlet stream name	Optional If no stream name is given, the profile described is assumed to apply to all reactors in a cluster.	-	VDOTPRO purge 0.19 300
	Time (Distance for flow reactor)	Required	sec (cm for flow reactor)	VDOTPRO purge 0.19 300
	Equivalent volumetric flow rate	Required	cm³ /min	VDOTPRO purge 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, or VDOT/`VDOTPRO` are specified or are nonzero, then a closed-system is assumed. FLRT/FPRO, SCCM/SCCMPRO, or VDOT/`VDOTPRO` is required for each INLET stream defined. Stagnation Flow CVD Reactors: FLRT/FPRO, 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 Multiphase PSR Plug Flow Reactor (PFR) Plasma PFR Honeycomb Monolith Reactor Rotating Disk CVD Reactor Stagnation Flow CVD Reactor
VEL Inlet Property	The gas-phase velocity at the inlet (for plug-flow reactors) or the maximum gas velocity at the inlet (for shear-flow reactors).
	Parameters	Optional/Reqd.	Units	Examples
	Velocity	Required	cm/sec	VEL 15
	Keyword Usage	Plug Flow Reactors: Optional keyword. Either VDOT or VEL must be specified, unless this is a restart run. Shear Flow Reactors: If the problem is in cartesian coordinates, then the average velocity equals two-thirds of the maximum velocity of the parabolic velocity profile. In cylindrical coordinates, the average velocity is half of the maximum velocity. If the keyword BLTK is given, a flat velocity profile will be used, that is, everywhere the velocity will be set equal to VEL except within a distance BLTK of the wall.
	Reactor Models	Cylindrical Shear Flow Reactor Honeycomb Reactor Planar Shear Flow Reactor Plasma Plug Flow Reactor Plug Flow Reactor
VELPRO Reactor Property	Flow velocity along the distance of a plug reactor.
	Parameters	Optional/Reqd.	Units	Examples
	Distance value	Required	cm	VELPRO 1.0 10.0
	Velocity	Required	cm/sec	VELPRO 1.0 10.0
	Keyword Usage	Optional keyword. By default, no profile is provided.
	Reactor Models	Plug Flow Reactor
VFFAC Reactor Property	The fraction of fuel vapor to be retained in the spray parcel after vaporization. If the bulk gas and the spray parcels are traveling at different directions and speeds, a large portion of the fuel vapor could be pushed out of its originating spray parcel. This vaporization rate model parameter can be used to improve the low vaporization rate issue of fuel components with high boiling point. Reducing the value of this parameter will increase the vaporization rate. This model parameter should have a value between 0 and 1 inclusive and will be applied to all injections of the same DI engine simulation.
	Parameters	Optional/Reqd.	Units	Examples
	Retention fraction	Optional	--	VFFAC 0.0
	Keyword Usage	Optional keyword. By default, the vapor retention fraction is set to 0.01.
	Reactor Models	Direct Injection Diesel Engine Simulator
VH Problem Type	Constant volume and enthalpy constraints.
	Keyword Usage	Optional keyword. Exactly one problem-type keyword must be included.
	Reactor Models	Chemical and Phase Equilibrium Calculations
VFRAC Reactor Property	Volume fraction of a bulk phase in the reactor. This specifies the overall composition of the reactor in terms of different bulk phases inccluding gas, liquid, and solid.
	Parameters	Optional/Reqd.	Units	Examples
	phase name	Required		VFRAC Gas 0.6
	volume fraction of a bulk phase in the reactor	Required		VFRAC jetFuel 0.4
	Keyword Usage	This keyword is used to specify the composition of the entire reactor. Bulk phase name follows the keyword. "Gas" indicates the gas phase. The composition is normalized to 1 at the start of simulation.
	Reactor Models	Closed Multiphase Reactor Multiphase PSR Reactor
VIS Inlet Property	Viscosity of the inlet gas mixture.
	Parameters	Optional/Reqd.	Units	Examples
	Viscosity	Required	g/(cm ⋅ sec)	VIS 0.01
	Keyword Usage	Optional keyword. By default, the viscosity is 0, that is, viscous drag is neglected.
	Reactor Models	Honeycomb Reactor Plasma Plug Flow Reactor Plug Flow Reactor
	Notes	A poise is equivalent to g/(cm ⋅ sec).
VISC Reactor Property	Viscosity of the mixture at 300 K. Required input for boundary layer corrections.
	Parameters	Optional/Reqd.	Units	Examples
	Viscosity at 300 K	Required	g/(cm ⋅ sec)	VISC 2.65E-4
	Keyword Usage	Optional keyword. By default, the viscosity is not set. This keyword is required for boundary layer corrections.
	Reactor Models	Normal Incident Shock
VLE Reactor Property	Vapor Liquid Equilibrium model for use with the phase transfer process. Additional parameters, `IDEAL` or `HENRY`, are required to specify the model. Value of 1, use the form: Here, , , are the three parameters input from following the first parameter. represents temperature in K. Value of 2, use the form: is the fifth parameter on the input line. This form is available only when pressure units are used specified for Henry's law using the keyword `UNITS`. Only one species on reactant and product side should be provided. This mapping is unique; a species may participate in only one `VLE` reaction.
	Parameters	Optional/Reqd.	Units	Examples
	Model name	Required	--	VLE / IDEAL/
	Model name	Required The model is specified by using one of these Model parameter keywords as the first parameter. `HENRY`: Henry's law for calculating equilibrium concentration levels in gas and liquid phases. Default form is dimensionless. This can be changed by optional keyword `UNITS`. `IDEAL`: Raoult's law for calculating equilibrium concentrations in gas and liquid phases.	--	CO2 = CO2(aq) 1.0 0.0 0. VLE/HENRY 1 3.34e-05 2400 298.15 /
	Model parameters	Required for `HENRY` parameter For `HENRY`, four or five parameters may be provided following `HENRY`. The first parameter, with an integer value of 1 or 2, indicates the type of temperature dependence for Henry's law. See Table 4.7: Auxiliary Keywords for Liquid Phase Reactions	K	CO2 = CO2(aq) 1.0 0.0 0. VLE/HENRY 1 3.34e-05 2400 298.15 /
	Keyword Usage	Optional keyword. By default, the heat loss from the reactor will be zero. See also QLOS and QPRO.
	Reactor Models	Multiphase Reactor
VOL Reactor Property	The volume of the reactor. In multi-zone models, users can enter zone volume fractions rather than exact zone volumes. The software will calculate the initial cylinder volume, normalize the volume fractions, and compute the exact zone volumes at the start of simulation. VOL is used to give Zone volumes and Zone volume fractions.
	Parameters	Optional/Reqd.	Units	Examples
	Volume	Required	cm³	VOL 1200
	Reactor number (PSR clusters only)	Optional If no number is given, the keyword is assumed to apply to all reactors in a cluster.	--	VOL 1200 1
	Keyword Usage	Optional keyword. By default, volume is required input for all PSRs
	Reactor Models	Closed Homogeneous Batch Reactor Closed Partially Stirred Reactor (PaSR) Closed Plasma Reactor Non-reactive Gas Mixer Multiphase PSR Partially Stirred Reactor (PaSR) Perfectly Stirred Reactor (PSR) Plasma PSR
VOL Reactor Property	The fraction of the total volume inside the cylinder for each zone in a Multi-Zone HCCI Engine model.
	Parameters	Optional/Reqd.	Units	Examples
	Zone volume fraction	Required	--	VOL 0.15 4
	Zone number	Required	--	VOL 0.15 4
	Keyword Usage	Optional keyword.
	Reactor Models	Multi-Zone HCCI Engine Simulator SI Engine Zonal Simulator
VOL Reactor Property	The initial specific volume of the gas mixture.
	Parameters	Optional/Reqd.	Units	Examples
	Specific volume of the gas mixture	Required	cm^3/g	VOL 1200
	Keyword Usage	Optional keyword. The user must specify two state variables and the composition to define the initial mixture.
	Reactor Models	Chemical and Phase Equilibrium Calculations
VOLC Reactor Property	Engine cylinder clearance volume.
	Parameters	Optional/Reqd.	Units	Examples
	Engine cylinder clearance volume	Required	cm³	VOLC 2.0
	Keyword Usage	Optional keyword. Any two of VOLC, VOLD, or CMPR must be specified.
	Reactor Models	IC HCCI Engine SI Engine Zonal Simulator
VOLD Reactor Property	Engine displacement volume, or the volume swept by the piston during compression.
	Parameters	Optional/Reqd.	Units	Examples
	Displacement volume	Required	cm³	VOLD 2.0
	Keyword Usage	Optional keyword. Any two of VOLC, VOLD, or CMPR must be specified
	Reactor Models	IC HCCI Engine SI Engine Zonal Simulator
VPARI Reactor Property/Model	Initial volume of a single spray parcel.
	Parameters	Optional/Reqd.	Units	Examples
	initial parcel vol	Required	cm³	VPARI 5.0
	Keyword Usage	Required keyword.
	Reactor Models	Direct Injection Diesel Engine Simulator
VPMOD Reactor Property/Model	Specify how the droplet surface temperature is determined. If VPMOD=0: uniform droplet temperature model, that is, the droplet surface temperature is the same as the droplet core temperature. If VPMOD=1: two temperature model; the droplet surface temperature is solved by the energy conservation equation at the droplet surface.
	Parameters	Optional/Reqd.	Units	Examples
	Surface temperature model	Required	--	VPMOD 1
	Keyword Usage	Optional keyword. Default: the uniform temperature model is used.
	Reactor Models	Direct Injection Diesel Engine Simulator
VPRO Reactor Property Profiles	Reactor volume profile specified as a function of time.
	Parameters	Optional/Reqd.	Units	Examples
	Time value	Required	sec	VPRO 1.0E-4 1.0
	Volume	Required	cm³	VPRO 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.	--	VPRO 1.0E-4 1.0 1
	Keyword Usage	For constrained-volume problems, VOL or VPRO must be specified. Otherwise, a default value of 1.0 is used for the initial reactor volume.
	Reactor Models	Closed Homogeneous Batch Reactor Closed Partially Stirred Reactor (PaSR) Closed Plasma Reactor Non-reactive Gas Mixer Partially Stirred Reactor (PaSR) Perfectly Stirred Reactor (PSR) Plasma PSR Multiphase PSR
VRS Reactor Property	Reflected shock velocity. If specified, it is used to determine the state of the gas after the shock. The reflected shock velocity is never used unless the incident shock velocity is also given.
	Parameters	Optional/Reqd.	Units	Examples
	Reflected shock velocity	Required	cm/sec	VRS 100
	Keyword Usage	Optional keyword. By default, no shock velocities are computed, but .
	Reactor Models	Normal Reflected Shock
VS Problem Type	Constant volume and entropy constraints.
	Keyword Usage	Optional keyword. Exactly one problem-type keyword must be included.
	Reactor Models	Chemical and Phase Equilibrium Calculations
	Notes	SV keyword.is equivalent.
VSHK Reactor Property	Incident shock velocity.
	Parameters	Optional/Reqd.	Units	Examples
	Velocity	Required	cm/sec	VSHK 3000.
	Keyword Usage	This input is required for all incident shock problems, and may be used for some reflected shock problems.
	Reactor Models	Normal Incident Shock Normal Reflected Shock
VTIM Reactor Property	The solution will be obtained with the volume as a function of time specified through a user programmed subroutine. SUBROUTINE PSVOLT(TIME, LOUT, VOL, DVDT) must be provided to specify the volume, and linked to the application program.
	Keyword Usage	Optional keyword. By default, volume is specified through VOL or VPRO.
	Reactor Models	Closed Homogeneous Batch Reactor Closed Plasma Reactor Non-reactive Gas Mixer Perfectly Stirred Reactor (PSR) Plasma PSR
	Notes	See also VPRO as an alternative way to specify volume as a function of time. See the Application Programming Interface Manual for more information on how to work with user subroutines.
VU Problem Type	Constant volume and energy constraints.
	Keyword Usage	Optional keyword. Exactly one problem-type keyword must be included.
	Reactor Models	Chemical and Phase Equilibrium Calculations
	Notes	UV keyword is equivalent.
VWALL Reactor Property	Specify a constant axial slip velocity at the walls.
	Parameters	Optional/Reqd.	Units	Examples
	Axial slip velocity	Required	cm/sec	VWALL 1.1
	Keyword Usage	Optional keyword. See also SLIP .
	Reactor Models	Cylindrical Shear Flow Reactor Planar Shear Flow Reactor
WBFB Solver	Specifies the b parameter of the Wiebe function. b must be greater than 0 and is set to 5.0 by default.
	Parameters	Optional/Reqd.	Units	Examples
	Value of the b parameter	Required	--	WBFB 9.0
	Keyword Usage	Optional keyword.
	Reactor Models	SI Engine Zonal Simulator
WBFN Solver	Specifies the n parameter of the Wiebe function. n must be greater than 0 and is set to 2.0 by default.
	Parameters	Optional/Reqd.	Units	Examples
	Value of the n parameter	Required	--	WBFN 4.0
	Keyword Usage	Optional keyword.
	Reactor Models	SI Engine Zonal Simulator
WDIF Solver	Use windward differencing on convective terms in the equations.
	Keyword Usage	Optional keyword. By default, windward differencing is used.
	Reactor Models	Diffusion or Premixed Opposed-flow Flame Premixed Laminar Burner-stabilized Flame Premixed Laminar Flame-speed Calculation
WELL Reactor Property	Flag indicating that a well mixed model will be used to simulate the molecular mixing within the computational particle.
	Keyword Usage	Optional keyword. By default, a well mixed model is assumed.
	Reactor Models	Closed Partially Stirred Reactor (PaSR) Partially Stirred Reactor (PaSR)
WENG Reactor Property	The reactor wall temperature will be obtained by solving energy conservation equations for the reactor wall. When WENG is used, all the external heat fluxes, that is, heat loss to the environment and heat exchange between the reactors in a network, are applied to the wall energy equation instead of the gas phase energy equation. Also, the heat generated by surface reactions will be included in the wall energy equation. If a surface has more than one material, the wall temperature is always assigned to the first material.
	Parameters	Optional/Reqd.	Units	Examples
	Thermal mass	Required	cal/K	WENG 0.1 500 1
	Heat transfer coefficient	Required	cal/(cm² ⋅ sec ⋅ K)	WENG 0.1 500 1
	Reactor number (PSR clusters only)	Optional If no number is given, the keyword is assumed to apply to all reactors in a cluster.	--	WENG 0.1 500 1
	Keyword Usage	Optional keyword. By default the surface temperature is fixed. The two required numbers on the keyword line specify the thermal mass of the reactor wall and the heat transfer coefficient between the inner wall surface and the gas mixture inside the reactor. The initial wall temperature can be specified by the keyword TSRF otherwise the gas temperature will be used. For Plug Flow Reactors the thermal mass parameter is described in units of cal/(cm ⋅ K).
	Reactor Models	Closed Homogeneous Batch Reactor Closed Plasma Reactor Honeycomb Reactor IC HCCI Engine Non-reactive Gas Mixer Perfectly Stirred Reactor (PSR) Plasma Plug Flow Reactor Plasma PSR Plug Flow Reactor SI Engine Zonal Simulator
WMIX Reactor Property	Width of the mixing region; used in defining the initial profile for the LINE or PLAT options.
	Parameters	Optional/Reqd.	Units	Examples
	Width of mixing region	Required	cm	WMIX 2.0
	Keyword Usage	Optional keyword. By default the width of the mixing region is XEND * 0.5.
	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
WOSP1 Reactor Property	Specify parameters of the Woschni heat transfer correlation for the compression period.
	Parameters	Optional/Reqd.	Units	Examples
	C11 in the average gas velocity correlation.	Required	--	WOSP1 2.28 0.318 0.0 1.57
	C12 in the Woschni correlation.	Required	cm/(sec - K)	WOSP1 2.28 0.318 0.0 1.57
	C2 in the Woschni correlation.	Required	--	WOSP1 2.28 0.318 0.0 1.57
	Ratio of swirl velocity to mean piston speed.	Required	--	WOSP1 2.28 0.318 0.0 1.57
	Keyword Usage	Optional keyword.
	Reactor Models	Multi-Zone HCCI Simulator IC HCCI Engine SI Engine Zonal Simulator
WOSP2 Reactor Property	Specify parameters of the Woschni heat transfer correlation for the combustion period.
	Parameters	Optional/Reqd.	Units	Examples
	C11 in the average gas velocity correlation.	Required	--	WOSP2 2.28 0.318 0.0 1.57
	C12 in the Woschni correlation.	Required	cm/(sec - K)	WOSP2 2.28 0.318 0.0 1.57
	C2 in the Woschni correlation.	Required	--	WOSP2 2.28 0.318 0.0 1.57
	Ratio of swirl velocity to mean piston speed.	Required	--	WOSP2 2.28 0.318 0.0 1.57
	Keyword Usage	Optional keyword.
	Reactor Models	Multi-Zone HCCI Simulator IC HCCI Engine SI Engine Zonal Simulator
WOSP3 Reactor Property	Specify parameters of the Woschni heat transfer correlation for the expansion period.
	Parameters	Optional/Reqd.	Units	Examples
	C11 in the average gas velocity correlation.	Required	--	WOSP3 2.28 0.318 0.0 1.57
	C12 in the Woschni correlation.	Required	cm/(sec - K)	WOSP3 2.28 0.318 0.0 1.57
	C2 in the Woschni correlation.	Required	--	WOSP3 2.28 0.318 0.0 1.57
	Ratio of swirl velocity to mean piston speed.	Required	--	WOSP3 2.28 0.318 0.0 1.57
	Keyword Usage	Optional keyword.
	Reactor Models	Multi-Zone HCCI Simulator IC HCCI Engine SI Engine Zonal Simulator
WPRO Reactor Property Profiles	Plasma power deposition profile specified as a function of time.
	Parameters	Optional/Reqd.	Units	Examples
	Time value	Required	sec	WPRO 1.0E-4 500
	Plasma power deposition	Required	watts	WPRO 1.0E-4 500
	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.	--	WPRO 1.0E-4 500 1
	Keyword Usage	Optional keyword. By default, no profile is provided.
	Reactor Models	Closed Plasma Reactor Plasma Plug Flow Reactor Plasma PSR
WSRC Reactor Property	Half-width of the Gaussian source term if the gas is being heated by an optional heat source. See Equation 15–12 of the Chemkin Theory Manual .
	Parameters	Optional/Reqd.	Units	Examples
	Half-width	Required	cm	WSRC 0.07
	Keyword Usage	Optional keyword. By default, the half-width is 0.0. This is a required keyword when QDOT is not 0.0.
	Reactor Models	Rotating Disk CVD Reactor Stagnation Flow CVD Reactor
XBTH Reactor Property	Specifies the bath gas composition. The [Species name ] (or number as it appears in the Pre-processor output) and desired mole fraction are required parameters. If at least one species in a phase has been set with the XBTH keyword, then all of the specified mole fractions for that phase are summed and normalized so that they add up to one. If no XBTH parameters have been specified for any species in the phase, then mole fractions for all species in that phase are set equal to one another.
	Parameters	Optional/Reqd.	Units	Examples
	Species name	Optional	--	XBTH H2 1.0
	Species number value	Optional	mole fractions	XBTH CH(S) 0.5
	Keyword Usage	Optional keyword. By default, the table output is determined by the ALL or NONE keyword.
	Reactor Models	Mechanism Analyzer
XCEN Reactor Property	Center of the mixing region; used in defining the initial profile for the LINE or PLAT options. Note that the fuel inlet is assumed to be located at .
	Parameters	Optional/Reqd.	Units	Examples
	Center of mixing region	Required	cm	XCEN 3.0
	Keyword Usage	Optional keyword. By default the center of the mixing region is XEND * 0.35.
	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
XEND Reactor Property	Physical length of the computational domain, or value of at the end of the domain. Depending on the reactor, the beginning of the domain is either 0.0 or the value of XSTR.
	Parameters	Optional/Reqd.	Units	Examples
	Channel length	Required	cm	XEND 25
	Keyword Usage	Required keyword.
	Reactor Models	Cylindrical Shear Flow Reactor Diffusion or Premixed Opposed-flow Flame Honeycomb Reactor Planar Shear Flow Reactor Plasma Plug Flow Reactor Plug Flow Reactor Premixed Laminar Burner-stabilized Flame Premixed Laminar Flame-speed Calculation Rotating Disk CVD Reactor Stagnation Flow CVD Reactor
XEST Reactor Property	For steady-state calculations, these are the estimated gas-phase mole fractions to begin the iteration. For transient problems, this keyword provides the initial values for the gas-phase mole fractions in the reactor. For example, XEST H2O 0.5 assigns an initial mole fraction of 0.5 to water vapor in the reactor.
	Parameters	Optional/Reqd.	Units	Examples
	Species name	Required	--	XEST H2O 0.5
	Initial fraction	Required	mole fractions	XEST H2O 0.5
	Keyword Usage	Transient cases: Required keyword; Steady-state cases: Optional keyword. By default, the initial or estimated gas-phase mole fractions are 0.0. For steady-state cases, if no XEST keywords are given, then an equilibrium calculation is performed to determine the initial estimates for the reactor composition.
	Reactor Models	Perfectly Stirred Reactor (PSR) Plasma PSR SI Engine Zonal Simulator
	Notes	The sum of all the estimated mole fractions should equal one. If they do not sum to one, they will be normalized and a warning message will be printed to the output file.
XIMN Reactor Property	Minimum mass or mole fraction value applied to intermediate species estimates, when the (default) equilibrium is used to determine product estimates. Ignored in the case that INTM keywords are present. In this case, the intermediate species fraction is initialized to be the average of its PROD2 and REAC values; or XIMN, if XIMN is greater than this average.
	Parameters	Optional/Reqd.	Units	Examples
	Intermediate fractions	Required	mole fractions	XIMN 1.0E-10
	Keyword Usage	Optional keyword. By default, the intermediate fraction is set to 0.
	Reactor Models	Premixed Laminar Burner-stabilized Flame Premixed Laminar Flame-speed Calculation
XINL Inlet Property	Inlet mole fraction of a species in the specific phase.
	Parameters	Optional/Reqd.	Units	Examples
	inlet stream name	Required	--	XINL C1_Inlet1 N2 1.0 1.0
	species name	Required	--	XINL C1_Inlet1 N2 1.0
	inlet mole fraction	Required	K	XINL C1_Inlet1 N2 1.0
	Keyword Usage	Required keyword for the specific phase if the inlet flow of the specific phase is non-zero.
	Reactor Models	Multiphase PSR Reactor
XML_OUTPUT_WRITE Output	Write output data to XML file.
	Keyword Usage	Optional keyword. By default, solution data will be written to XML file.
	Reactor Models	All
XMLI Cluster Property	Read a solution from the XML Solution File used for initialization ( XMLdata.zip), which may be a solution from any other Reactor Model (see also RSTR). When initialization ( XMLI) is used from an XML Solution File with spatial profiles (that is, 1-D or channel-flow models), the initial values are actually averages of the profiles stored in the XML Solution File. The integral averages are calculated using trapezoidal integration rules.
	Keyword Usage	Optional keyword. By default, the program does not look for an XML Solution File used for restart or initialization.
	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 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
	Notes	For shear-layer flow solutions, we use the value integrated over the height (or radius) and divided by the cross-sectional area for the specified axial-distance location. For Opposed-flow Flames and CVD Reactors, we use the value integrated over the spatial domain, divided by the total axial distance.
XMLS Cluster Property	Use a previously stored XML Solution File or the XML Solution File from an upstream reactor to initialize the inlet conditions of this inlet.
	Keyword Usage	Optional keyword. By default, the program does not look for an XML Solution File used restart or initialization.
	Reactor Models	Cylindrical Shear Flow Reactor Diffusion or Premixed Opposed-flow Flame Honeycomb Reactor Non-reactive Gas Mixer 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 Stagnation Flow CVD Reactor
XRES Restart	Force the starting distance for the new solution to be this value and ignore the value of distance from the XML Solution File used for restart or initialization.
	Parameters	Optional/Reqd.	Units	Examples
	Initial distance	Required	cm	XRES 10
	Keyword Usage	Optional keyword. By default, the value of the XML Solution File is used during a continuation or restart run.
	Reactor Models	Honeycomb Reactor Plasma Plug Flow Reactor Plug Flow Reactor
XRST Restart	This keyword is valid when using RSTR option. In this case, select the values to use in restart as those corresponding to the distance that is closest to (greater than or equal to) the specified distance.
	Parameters	Optional/Reqd.	Units	Examples
	Distance	Required	cm	XRST 5.0
	Keyword Usage	Optional keyword. By default, the point where the previous solution ended is used.
	Reactor Models	Cylindrical Shear Flow Reactor Planar Shear Flow Reactor
XSDF Reactor Property	Default value for a momentum-transfer cross-section between electrons and each species. This value is used for all species not specified with the XSEK keyword.
	Parameters	Optional/Reqd.	Units	Examples
	Momentum-transfer cross-section	Required	cm²	XSDF 1.0E-16
	Keyword Usage	Optional keyword. By default, the cross-section value is 0. In a plasma problem the user must either specify XSDF or include an XSEK keyword for all species except electrons.
	Reactor Models	Closed Plasma Reactor Plasma Plug Flow Reactor Plasma PSR
XSEK Reactor Property	Momentum-transfer collision cross-section between electrons and a specified species. For example, "XSEK AR 1.0E-16" would indicate a momentum-transfer cross-section of 10^-16 cm² between electrons and argon atoms. For any species not specified by the XSEK keyword, a user-specified default value will be used.
	Parameters	Optional/Reqd.	Units	Examples
	Species	Required	--	XSEK AR 1.0E-16
	Momentum-transfer cross-section	Required	cm²	XSEK AR 1.0E-16
	Keyword Usage	Optional keyword. By default, the cross-section value is 0. In a plasma problem the value for every species is specified by the XSDF keyword.
	Reactor Models	Closed Plasma Reactor Plasma Plug Flow Reactor Plasma PSR
XSRC Reactor Property	Height above the disk which is the center of a Gaussian-shaped power source. See Equation 15–12 of the Chemkin Theory Manual .
	Parameters	Optional/Reqd.	Units	Examples
	Height	Required	cm	XSRC 0.6
	Keyword Usage	Optional keyword. By default, the height is 0.0.
	Reactor Models	Rotating Disk CVD Reactor Stagnation Flow CVD Reactor
XSTR Reactor Property	The beginning of the computational domain. For burner-stabilized flames, this is the burner location.
	Parameters	Optional/Reqd.	Units	Examples
	Inlet axial position	Required	cm	XSTR 1.5
	Keyword Usage	Optional keyword. By default, the starting or inlet axial position is 0.
	Reactor Models	Honeycomb Reactor Plasma Plug Flow Reactor Plug Flow Reactor Premixed Laminar Burner-stabilized Flame Premixed Laminar Flame-speed Calculation Rotating Disk CVD Reactor Stagnation Flow CVD Reactor
XTMP Reactor Property	If TSRF is used to specify the surface temperature, the application will set the surface temperature to TINL at and smoothly ramp the temperature up to TSRF at a distance of XTMP.
	Parameters	Optional/Reqd.	Units	Examples
	Distance between TINL point and TSRF point	Required	cm	XTMP 0.25
	Keyword Usage	Optional keyword. By default, the distance is set to 0.5.
	Reactor Models	Cylindrical Shear Flow Reactor Planar Shear Flow Reactor
ZNDB Reactor Property	Calculates the ZND structure behind the incident shock with the boundary layer correction. The gas-mixture properties before the incident shock must be provided. The speed of the incident shock is set to the Chapman-Jouguet detonation wave speed, which is determined from the gas properties before the shock.
	Keyword Usage	Optional keyword.
	Reactor Models	Normal Incident Shock reactor model
ZNDC Reactor Property	Calculates the ZND structure behind the incident shock. The gas mixture properties before the incident shock must be provided. The speed of the incident shock is set to the Chapman-Jouguet detonation wave speed which is determined from the gas properties before the shock.
	Keyword Usage	Optional keyword.
	Reactor Models	Normal Incident Shock reactor model
ZONEAVG Output	Flag to store only the zone-average solution data in the Multi-Zone HCCI Engine Simulator.
	Keyword Usage	Optional keyword. By default, all solution data is stored in the Multi-Zone HCCI Engine Simulator output.
	Reactor Models	Multi-Zone HCCI Engine Simulator SI Engine Zonal Simulator