ansys-chemkin 2025.2.1

PyChemkin provides Pythonic interface to Ansys chemkin utilities and reactor models

Contents

• Overview

  • Installation

    • Verifying the installation

  • Basic usage

  • Documentation and issues

Overview

PyChemkin (Ansys-chemkin package) provides pythonic access to Ansys Chemkin. It facilitates programmatic customization of Chemkin simulation workflow within the Python ecosystem and permits access to Chemkin property and rate utilities as well as selected reactor models:

• Process Chemkin-compatible gas-phase mechanisms

• Evaluate species and mixture thermodynamic and transport properties

• Compute reaction rate of progress and species rate of production (ROP)

• Combine gas mixtures isothermally or adiabatically

• Find the equilibrium state of a gas mixture

• Run gas-phase batch reactor models

For more information on Chemkin, see the Ansys Chemkin page on the Ansys website.

Installation

pip is the preferred installation method. You can use pip to install PyChemkin.

pip install ansys-chemkin

Note

Please refer to the Prerequisites for all required Python extensions to install/run PyChemkin.

Verifying the installation

Invoke the Python interpreter interface from Windows’ command prompt and try to import the ansys-chemkin package as

import ansys.chemkin

• PyChemkin is correctly installed if python returns

Chemkin version number = xxx

• It is likely there is no Ansys product installed locally if python does not return anything.

• The local Ansys Chemkin version needs to be updated to at least version 2025 Release 2 if Python returns

** PyChemkin does not support Chemkin versions older than 2025 R2

Note

A valid Ansys license is still required to run PyChemkin after the installation.

For more information, see Getting Started.

Basic usage

Here is a PyChemkin project to compute the density of mixture air. This code shows how to import PyChemkin (Ansys Chemkin) and use some basic capabilities:

import os

# import PyChemkin
import ansys.chemkin as chemkin

# create a Chemistry Set for GRI 3.0 mechanism in the data directory
mech_dir = os.path.join(chemkin.ansys_dir, "reaction", "data")
# set up mechanism file names
mech_file = os.path.join(mech_dir, "grimech30_chem.inp")
therm_file = os.path.join(mech_dir, "grimech30_thermo.dat")
tran_file = os.path.join(mech_dir, "grimech30_transport.dat")
# instantiate Chemistry Set 'GasMech'
GasMech = chemkin.Chemistry(chem=mech_file, therm=therm_file,  tran=tran_file,  label='GRI 3.0')
# pre-process the Chemistry Set
status = GasMech.preprocess()
# check preprocess status
if status != 0:
    # failed
    print(f'PreProcess: error encountered...code = {status:d}')
    print(f'see the summary file {GasMech.summaryfile} for details')
    exit()
# Create Mixture 'air' based on 'GasMech'
air = chemkin.Mixture(GasMech)
# set 'air' condition
# mixture pressure in [dynes/cm2]
air.pressure = 1.0 * chemkin.Patm
# mixture temperature in [K]
air.temperature = 300.0
# mixture composition in mole fractions
air.X = [('O2', 0.21), ('N2', 0.79)]
#
print(f"pressure    = {air.pressure/chemkin.Patm} [atm]")
print(f"temperature = {air.temperature} [K]")
# print the 'air' composition in mass fractions
air.list_composition(mode='mass')
# get 'air' mixture density [g/cm3]
print(f"the mixture density = {air.RHO} [g/cm3]")

For comprehensive usage information, see the Tutorials in the PyChemkin documentation.

Documentation and issues

Documentation for the latest stable release of PyChemkin is hosted at PyChemkin documentation.

In the upper right corner of the documentation’s title bar, there is an option for switching from viewing the documentation for the latest stable release to viewing the documentation for the development version or previously released versions.

User manuals and tutorials for Chemkin can be found at Chemkin Documents.

On the PyAnsys Chemkin Issues page, you can create issues to report bugs and request new features. On the PyChemkin Discussions page or the Discussions page on the Ansys Developer portal, you can post questions, share ideas, and get community feedback.

To reach the project support team, email [e-mail].