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Simulating (2D) Chemical Reaction in Porous Medium, DEFINE_VR_RATE,Divergence detected in AMG Solver

    • ajithjec
      Subscriber
      In 2D Model, Reaction in porous Zone, Error occurs on hooking UDF , DEFINE_VR_RATE in Fluent, The error spikes just after running calculation after 1st iteration.nDivergence detected in AMG Solver: TEMPERATUREnDivergence detected in AMG solver species 0nand Divergence detected in AMG solver species 1...2..3..4nFloating-point exception error object #fnAny solution for this, Does anybody have previous issues like this?n
    • RK
      Ansys Employee
      Hello, nPlease refine the mesh if you have not already done so. nUse the second order schemesnYou might also want to look into other stabilization parameters : https://ansyshelp.ansys.com/account/secured?returnurl=/Views/Secured/corp/v202/en/flu_ug/flu_ug_uns_sec_mg_criteria_amg.htmln
    • ajithjec
      Subscriber
      Hi Rahkumar, thank yor for your reply. But I am doubt , as the settings works , means iterating when udf was unhooked. How comes this happens? If any issues in meshing it will show the error in all settings na?nI used second order schemes. Tried the stabiliation, F cycle for species.nStill cant resolve the issue. The same 2D model used for DEFINE_SR_Rate and its iterating with out error. Only DEFINE_VR_Rate this issue coming....n
    • ajithjec
      Subscriber
      The divergence error can be due to the above-mentioned issues. But in my case it was due to the reaction rate too big. The temperature varies a lot during switching on the reaction and iterating. Due to this the reaction rate reaches a big value which is not realistic. In the UDF i made some min and max limit criteria and the issue solved now.n
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