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Why there is temperature gradient near adiabatic wall boundary condition?

    • roytorc
      Subscriber

      Hi,


      I am modelling the turbulent non-premixed flame touching the adiabatic surface (by set heat flux of the wall =0 in thermal boundary condition). However, there is a temperature gradient near the wall which I don't understand how is that possible. I've checked the heat flux across the boundary and it is 0. Please advise.


       


    • Amine Ben Hadj Ali
      Ansys Employee
      Check temperature of the wall and near wall cell temperature
    • roytorc
      Subscriber

      After checked, the values are:


      wall --> Contour level 6, value in [820.98102, 907.81116].


       


       


      near wall cell --> Contour level 10, value in [1168.3018, 1255.1318].


       


      I still don't understand why there is the temperature gradient. Please help advise.

    • Amine Ben Hadj Ali
      Ansys Employee
      No on the wall check the wall temperature then on the same wall the cell temperature.
    • roytorc
      Subscriber

      I checked for wall temperature and adjacent wall temperature from the contour plot, is it the right way to check?


      Wall Temperature


      Adjacent wall temperature


      If so, wall temp = [973.76892, 984.96167]


      adjacent wall temp = [1097.0457, 1105.3676]


      Why is this situation occur?


       

    • Amine Ben Hadj Ali
      Ansys Employee
      That is not ideal so. You need to quantify it in better way. Either you use UDF or plot along the line wall and static temperature.
    • Amine Ben Hadj Ali
      Ansys Employee
      Or look after the gradients which you enable under solve set expert.
    • roytorc
      Subscriber

      Is this mean Fluent assign some temperature value to the adiabatic wall? By the way, I cannot see the gradient option in sove>set>expert


       


    • Amine Ben Hadj Ali
      Ansys Employee
      Keep temporary... to yes to see gradients for Post processing
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