Floating Point Error: Solidificaiton/Melting with PCM 2D

    • RLester5




      The inlet is the rectangle located on the top right corner of the mesh with the outlet right beside it as the smaller rectangle.

      the left most side is a cut out where two copper fins would be that wall will be set up as copper later on.

      Mesh Quality



      Edge sizing 1


      Edge sizing 2

      Face 1

      Face sizing 1



      Viscous Model


      Energy is also enabled.


      My fluid is a PCM with 3 piecewise-linear points for Density, Specific heat, and thermal conductivity.


      I am using standard initialization at 273.15k no other inputs modified.
      I am running the calculation using adaptive time stepping method with the following parameters:

      Time step


      The floating point error occurs withing 10 iterations of the start of the calculation, with the following output:


      part a

      part b

      part c


      I am not too sure what else I need to do to fix this error. I've tried the time step size and changing mesh stats.

      Please let me know if you have any ideas or require any more information.




    • RK
      Ansys Employee

      Hello Ryan, 

      What are the boundary conditions you using? 

    • RLester5

      Hey Rahul,

      Are you looking for the individual conditions, I am not sure what exactly you're asking for.

      I have 5 conditions:
      Condensing body - Interior
      Copper                 - Wall
      Inlet                      - Velocity Inlet
      Outlet                   - Pressure Outlet
      Steel                     - Wall

      On the copper and steel I set temperatures of 4k and 273.5k respectively.

      I've been playing with changing the outlet to a wall as well since I don't really need it, but I am still getting this crazy result of the temps shooting up past the 5000k limits.
      I even patch the condensing body at 273.5k at the start.

      Let me know if you'd like more pictures or more explanation, and thanks for your help!


    • RLester5

      Dear Rahul,

      I have just attached a picture of the result of the run. This is a contour of total temp. After confirming that I indeed patched for 273.5k after 3 iterations i get the failure and the output shows the inside temp at 1k with 5000k scattered around. I have never seen results like this, making me believe this is a small error I'm just overlooking.

    • RLester5

       Dear Rahul,

      As I'm sitting here creating various iterations with and without inlet/outlets, various materials, different model types, I'm noticing when I look at path-line graphics after a run there seems to be a pulling/convergence occurring towards the center of the "condensing body" . To add to this, I get a bunch of messages repeating "Can't figure which cell particle is going to -- ABORT
      Cannot find intersecting face for particle XXXXX -- ABORT "

      I realize I'm just dumping information onto you, but I am trying to encompass all problems I'm encountering to best depict the possible issues.

      Looking forward to hearing from you.


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