Fluids

Fluids

How to plot mass diffusivity and thermal diffusion coefficient of gaseous mixtur

    • 164170007
      Subscriber

      I selected kinetic theory in mass diffusivity and thermal diffusion coefficient of mixture template panel but only thermal diffusion coefficient is coming in the plotting panel of XY plot (under species). I used custom defined functions for other variables to calculate, but in that case I dont think its gonna work, correct me if I am wrong.

      Thanks in advance.

    • Rob
      Ansys Employee

      It may depend on how you defined species diffusivity. Try some of the other options in the Species>Mixture panel. 

    • 164170007
      Subscriber

       

      Hello Rob, As I mentioned I used “kinetic theory” for defining both thermal and mass diffusion coefficient and I want to plot those results. I am sure there would be some provision of plotting those results. I checked fluent theory guide and (see this link https://www.removed! EDIT: Links to rogue copies of Ansys documentation will be deleted, Rob) they mentioned some formula.

       

      Regards,

      Vinay Chandraker

       

    • Rob
      Ansys Employee

      Looks to be there in my version (2023R1 at present as I'm testing something). 

      That set of documentation is incredibly out of date, and a technical breach of Ansys copywrite: the link will not be there much longer. If you click on Help in Fluent you'll find the current version. 

    • 164170007
      Subscriber

      Can you please send me the screenshot of your mixture template and contours panel? ( in which you used kinetic theory for thermal and mass diffusion coefficient)

      Regards,

      Vinay Chandraker

    • Rob
      Ansys Employee

       

    • 164170007
      Subscriber

      Can you send the screenshot of contours panel under species tab so that I will get an idea about binary diffusion coefficients of different species.

    • Rob
      Ansys Employee

      Look up the thread. My example had 3 species in the mixture. What are you seeing?

    • 164170007
      Subscriber

      Hello Rob,

      I am able to see two screenshots. One is for nitrogen material and second is mixture template, but I asked for the contours panel, because when we choose kinetic theory in mixture template for mass and thermal diffusion coefficient it sets automatically and I would like to plot the binary diffusion coefficient for those values which has been set up by fluent automatically. Please see the attached screenshot.

      Here only thermal diffusion coefficient is coming but mass diffucion coefficients are not there, when I choose kinetic theory in mixture template.

      Regards,

      Vinay

    • Rob
      Ansys Employee

       

      Weird. I'd missed the thermal diffusivity in the Species model panel, given most systems are turbulent I've never tended to use it. 

       

       

    • 164170007
      Subscriber

      Hello Rob,

      In your case diffusivities are coming in the contours panel despite choosing kinetic theory, then what would be the issue in my case. (My case is laminar and I have choosen kinetic theory for viscocity, thermal, conductivity of individual species and kinetic theory in mixture template for diffusion coeffcient and thermal diffusion coefficient).

      Is it because I am using ansys 2020R2 and you are using newer version?

      If its version issue please let me know.

      Regards

    • Rob
      Ansys Employee

      I'm using 2022R2, and looks like I can pick kinetic theory for components and then again for the diffusivity options. 

    • 164170007
      Subscriber

      Hello Rob,

      I am also using ANSYS 20202 R2, then what would be the issue there?

      Can I share my case file here, so that you can look? Please let me know.

      Regards,

      Vinay 

    • Rob
      Ansys Employee

      Possibly, I've not got 20R2 at present so can't check. 

      If you post files the wider community can have a look. However, Ansys staff are not permitted to open or download anything so I won't be able to do anything. 

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