Fluids

Fluids

mixture multiphase model (convergent-divergent nozzle)

    • Anwar94
      Subscriber

      Hello everyone,


       


      I'm doing a simulation for multiphase flow (mixture model) to validate paper’s results.


      By the way, in the paper, the authors used this setup:


      - Separation implicit solver.


      - SIMPLE scheme were applied to resolve pressure-velocity coupling equation.


      - the k-ε two-equation turbulent model, standard wall functions were employed to the flow in near-wall region.


      - The second-order upwind difference scheme was also applied to improve the computational accuracy by


      discretizing the physical parameters of volume control interface.


      - the convergence precision 10-6 of the residual monitor for energy equation.


      - a mixture model was selected with inter-phase velocity slip taken into account.


       


      - conversion of mass source and energy source were compiled by User Defined Function (UDF) and coupled to flow functions. ( I have problem in this point, so I used  evap/cond Lee model)


      The main problem that I faced is instability in the solution, while I find the under-relaxation factors  and evaporation frequency so significant factors in the solution.


      Hope someone who has the experiences in this can help me. So, please find attached pictures that compares between my results and the paper’s result, and give me your feedback  .


      Regards,


      Anwar





    • Karthik R
      Administrator

      Is the model coded in the UDF different from the Lee model you are using?


      Also, what is your convergence like? Are you able to obtain a converged solution?


      Is everything (boundary conditions, equations being solved, initial conditions) between the model you are running and the results you are comparing with the same?


      Thanks.


      Karthik

    • Anwar94
      Subscriber

      Thanks for your reply. 


      In my solutoin, I didn't use any UDF (so, may be the problem in this point)


      In addition, my solution is convergenced but when it convergenced, it happens there problem in the solution which don't match the paper's results.


      For boundary conditions and initial conditions I think we are the same.


      Regards,


       


      Anwar


       

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