Importing Chemkin File : Hydrogen-Oxygen combustion modelling in Ansys Fluent

- October 18, 2023 at 10:51 pm
  Wimukthi Nuvan Senarathna Panchanadayalage
  Subscriber
  1. Hi..I am Wimukthi. At the moment I am modelling hydrogen-oxygen combustion in ansys fluent. My model is a 2D half circle on ground filled with oxygen and air mixture. For that I have to import Chemkin reaction file to ansys fluent. However, Chemkin has different units for pre-exponential factor (mol/cm*sec*K) and Activation energy in the rate constant of the reaction [cal /mole]. I wonder whether I have to change the units of coefficients in the Chemkin code. Or will it work if I change the units in Ansys Fluent to match with Chemkin default units as shown below:
  2. Recently I used the following code for hydrogen oxygen reaction. I wonder whether it gives correct results:
  3. When we define the reaction, is the mixture also defined? If I want to change the hydrogen to air ratio to 2:1. Could you assist me to set that ratio. (Pls note that I have no real inlet in the 2D half circle domain. The inlet is only zero velocity boundary. What I need is to ignite the hydrogen oxygen mixture in the domain.
  
  Thank you,
  Wimukthi
- October 31, 2023 at 9:17 am
  
  vinaraya
  Ansys Employee
  
  Hi Wimukthi, Please find below the response to your queries.
  1). You dont have to convert the units. Fluent does it for you. The unit of Pre-exponential factor depends on the order of reaction + the unit of K appears in pre-exponetial factor only if Temp exponent is present.
  2) You can refer the CHEMKIN Input Manual to verify the syntax used. At a first glance, I dont see any issue with your mechanism code.
  3) When you enable reaction modelling using species transport (a mixture template gets created) with the species in the imported mechanism. You can initailize your 2D domain with the mass fraction of H2 and air as per your choise. You can patch a high temperature within your domain to initiate combustion.
  
  Regards,
  Vijay