All Ansys Chemkin projects require data in the form of chemistry sets. The mechanics of including chemical information in the input files, including a description of data formats, is covered in the Chemkin Input Manual. The Chemkin Theory Manual describes the formulation of the various forms of the chemical rate expressions. This chapter discusses the kinds of chemical information that make up a chemistry set, and how to go about acquiring such data.
A chemistry set consists of several input files, each containing a different type of chemical data. The collection of chemical data in a given chemistry set is often called a reaction mechanism. The major components of a chemistry set are:
a file containing thermochemical data for the chemical species of interest,
a file containing a description of the reactions occurring in the gas phase,
a file containing a description of the reactions occurring at the gas-surface interface or on the surface, and
A set of gas-phase and/or surface reactions are generally developed using specific thermochemical data. Thus, the gas-phase kinetics, surface kinetics, and thermodynamic data are most reliable when used together as a set in reacting-flow simulations. Once a chemistry set is defined in Ansys Chemkin, it can be saved and referenced easily in future simulations.
Different Reactor Models require different combinations of chemistry set components to be supplied. In Table 3.1: Chemistry Set Components Required for Various Reactor Models, R means the component is required, O means the component is optional and X means the component is not used. As part of the software installation, Ansys provides some chemical data, particularly thermochemical and transport-property data, which provides a starting point for assembling new chemistry sets. This information is discussed in more detail in the following sections.
Table 3.1: Chemistry Set Components Required for Various Reactor Models
|
|
|
Thermo Data |
Gas-phase Chemistry |
Surface Chemistry |
Transport Data |
|---|---|---|---|---|---|
|
Icon |
Reactor Model |
therm.dat |
chem.inp |
surf.inp |
tran.dat |
| Equilibrium | R | R | O | X |
| Mechanism Analyzer | R | R | O | O |
| Multi-zone HCCI Engine | R | R | X | X |
| SI Engine Zonal Simulator | R | R | X | X |
| IC HCCI Engine | R | R | X | X |
|
|
IC HCCI Engine |
R |
R |
X |
X |
| Closed Homogeneous | R | R | O | X |
|
|
Closed Multiphase |
R |
R |
O |
X |
| Closed PaSR | R | R | X | X |
| Closed Plasma | R | R | O | X |
| Ignition Progress Variable Library | R | R | O | X |
| PSR | R | R | O | X |
| Plasma PSR | R | R | O | X |
| PaSR | R | R | X | X |
| PFR | R | R | O | X |
| Plasma PFR | R | R | O | X |
| Planar Shear Flow | R | R | O | |
| Cylindrical Shear Flow | R | R | O | R |
| Honeycomb Monolith | R | R | R | X |
| Pre-Mixed Burner | R | R | X | R |
| Pre-Mixed Stagnation Flame | R | R | X | R |
| Flame Speed | R | R | X | R |
|
Flame Speed Table Generator | R | R | X | R |
| Opposed-flow Flame | R | R | X | R |
| Extinction Flame Simulator | R | R | R | R |
|
|
Diffusion Flamelet Generator |
R |
R |
X | X |
| Stagnation Flow | R | R | R | R |
| Rotating Disk | R | R | R | R |
| Incident Shock | R | R | X | X |
| Reflected Shock | R | R | X | X |
| LPCVD Thermal Analyzer | X | X | X | X |
| LPCVD Furnace | X | X | X | X |
