Fluids

Fluids

Hydrogen air combustion mechanism

    • Tianxu
      Subscriber

      Hi,


      I'm using hydrogen air reaction mechanism for my shock tube simulation, the mechanism includes 11 species and 23 reaction. Third body efficiencies is included in this case. 


      I'm wondering what efficiency factor should I specified for each species, because there are different efficiency factor for some species which specified in the chemkin input file. The chemkin input file is attached.


      For example, H2O has efficiency factor of 18.6 for the reaction H + O2 + M <=> HO2 + M and efficiency factor of 5 for the reaction H + OH + M <=> H2O + M.


      So for the third body efficiency input box, should I choose 18.6 or 5 for H2O?


      Thanks for helping me out!

    • Tianxu
      Subscriber

      The default third body efficiency input box is shown below:



       

    • DrAmine
      Ansys Employee

      Just read the mechanism and the parameters are parsed directly. 

    • DrAmine
      Ansys Employee

      Please use a recent Ansys Fluent Version

    • Tianxu
      Subscriber

      Hi Amine,


      I'm usinig the Uni PC, unfortunately version 19.2 is my only option.


      So, do I just import the mechanism, enable the third body efficiency and leave the default efficiency parameters? 


      Sincerely,


      Tianxu 

    • DrAmine
      Ansys Employee

      It will be enabled automatically. Yes 19.2 is old and If I remember there were some small issues which has been fixed might be important for your case here. Try to use a newer version.

    • Tianxu
      Subscriber

      Hi Amine,


      Just to comfirm that I don't need to opt 'Include backward reaction' and 'Third-Body Efficiencies', shown in the figure below. Since they are enabled automatically.



      Sincerely,


      Tianxu

    • DrAmine
      Ansys Employee
      Mark as is solved.
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