Fluids

Fluids

RPI boiling model

    • Nikesh
      Subscriber

      Dear all Friend
      I have a problem with a subcooled boiling model. I'm looking for some help from people who are familiar with the RPI Wall boiling model in CFX
      I am trying to model sub-cooled boiling in a straight heated tube to find DNB type CHF . The problem is set up by steady,constant property material, liquid as continuous while vapour as polydispersed fluid,buoyant,Homogenous turbulence, Homogenous MuSiG Model and RPI wall boiling model.
      My problem is as following: Depending on the problem condition the calculation crashes after some number of iterations following a huge number repetitions of the following message:

      " cal_TSUP1 WARNING: Changing upper bound for heat partition algorithm "

      and at the end the error message is the following:

      " ERROR #001100279 has occurred in subroutine ErrAction. Message: Heat partitioning algorithm failed to fix upper bound of bisection

      Details of error:-


      Error detected by routine FNDFIL CFNAME = * CRESLT = OLD
      "

      Can anybody help about this problem? 
      thanks to all

    • DrAmine
      Ansys Employee
      Bisection algorithm failed. Try using small time scales and ramp the heat flux.
    • Nikesh
      Subscriber

      I tried by doubling the heat flux and reducing the physical time step by the order of 2 but again the algorithm is failing. 


      Please help


      Thank you

    • DrAmine
      Ansys Employee
      You need to reduce heat flux or ramp it over iteration interval.
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