10 Replies Latest reply on Feb 26, 2014 2:02 AM by Jared Conway

    transient Thermal Study 0 °K after nearly half of duration

    Evox Padubal

      Hey guys,

       

      i have a transient thermal model to calculate.

      The rough principle looks like in this picture:

      http://ww3.cad.de/foren/ubb/uploads/Evox/Schema.jpg

      On each side is a mounting and a peltier element attached to the cube in the center, which has a drilling in the middle for some fluid.

       

      Now i have 2 variations of this model, with a duration of 540 seconds.

      1. constant power of 10W per peltier -> good results till 237sec,after that everything is just at 0°K

      2. pulsed power of 20W per peltier -> good results till 257sec,after that everything is just at 0°K

       

      I've checked everything.

      - Materials are okay..no one is using any graphs for the thermal specifications

      - Thermal Loads:

        1. is constant at 10W per each inner surface of the peltier, so 2x 10W

        2. is the same but with 20W changing the side, every 2 seconds over the whole duration of 540sec

      - thermal resistance between contact surfaces are all fine

      - RAM,CPU,HDD: there are more ressources than i need

       

      I can't figure out where the problem is....i tryed it on 2 different computers, several times...every time i get the same results.

      It jumps from one step to the next from good values to 0°K, which can definitely not be possible.

      Ther must be sth. wrong with the calculation process, i think.

       

      oh and the pc is calculatin all 540 steps! the simulation doesen't crash, or sth like that...

        • Re: transient Thermal Study 0 °K after nearly half of duration
          Evox Padubal

          even if i deactivate all thermal contact resistances and stuff, except the global contact, it's still not working.

          i double checked my thermal loads, theres everything okay with them..no wrong checked checkboxes or values...

          and i can't find any helpful log-file or sth else.

          does anyobody know if there is sth. like a log file, to see in detail whats going on in every step? maybe this would help me...

            • Re: transient Thermal Study 0 °K after nearly half of duration
              Evox Padubal

              an now i had a second problem, which may could be connected to this one...

              https://forum.solidworks.com/thread/63792

               

              but the hstat.exe continued working...so...i don't know if the crash affects the simulation calculation...

                • Re: transient Thermal Study 0 °K after nearly half of duration
                  Evox Padubal

                  i found this in a *.TEM-file

                  its quite strange, because Tmax and Tmin ar rising until the last frame, but if i try to show them in solidworks as colored picture there is the problem between 237sec (nice temperature) and 238sec (0°K, everywhere)

                   

                  Nodal Gradient and Heat Flux at time step =   237  (Time =  237.00000    )
                  --------------------------------------------------------------------------------

                      Node  Gradient_X      Gradient_Y      Gradient_Z      Heat Flux_X     Heat Flux_Y     Heat Flux_Z
                  ==========================================================================================================

                  Minimum/Maximum Temperature Gradient and Heat Flux

                  Node         174229           25723           25723          112539          174229          174229
                  Min.     -868167.75      -21751.786      -55834.693      -62176.810      -78356.016      -404180.08   
                  Node         147593          174229          174229          174229           98951           97420
                  Max.      75435.813       326483.41       1684083.7       208360.25       725212.91       47753.613   


                  Nodal Heat Balance at time step =   237    (Time =  237.00000    )
                  --------------------------------------------------------------------------------
                      Node     Applied      Conduction      Convection       Radiation        Reaction   Sys. Internal         Balance
                  Input     19.999998      1.63923381E-06   0.0000000       0.0000000      2.29901666E-05   3.7474330       23.746704   
                  Output  -3.31119021E-07 -1.31094735E-05   0.0000000       0.0000000     -2.49573113E-05  -22.484595      -22.483882   

                  Total Heating applied to the system      =  19.999998   
                  Cooling at nodes with prescribed temp.   =-1.96714469E-06
                  Increase in the system internal energy   =  18.737162   
                  System heat balance=                     =  1.2628221   
                  For greater heat balance accuracy, reduce the solution convergence norm.


                  Nodal temperature results at time step =   238     (Time =     238.000    )
                  --------------------------------------------------------------------------------

                      Node   Temperature      Node   Temperature      Node   Temperature      Node   Temperature
                  ================================================================================================


                     Tmax  =  313.17043   
                     Tmin  =  290.14999   

                  Nodal Gradient and Heat Flux at time step =   238  (Time =  238.00000    )
                  --------------------------------------------------------------------------------

                      Node  Gradient_X      Gradient_Y      Gradient_Z      Heat Flux_X     Heat Flux_Y     Heat Flux_Z
                  ==========================================================================================================

                  Minimum/Maximum Temperature Gradient and Heat Flux

                  Node         174229           25723           25723          112539          174229          174229
                  Min.     -869330.13      -21745.018      -55817.339      -62175.126      -78460.917      -404721.24   
                  Node         147593          174229          174229          174229           98951           97420
                  Max.      75491.805       326920.49       1686338.5       208639.23       725378.95       47775.686   


                  Nodal Heat Balance at time step =   238    (Time =  238.00000    )
                  --------------------------------------------------------------------------------
                      Node     Applied      Conduction      Convection       Radiation        Reaction   Sys. Internal         Balance
                  Input     19.999998      1.64362089E-06   0.0000000       0.0000000      2.29308425E-05   3.7467092       23.745981   
                  Output  -3.31119021E-07 -1.30948440E-05   0.0000000       0.0000000     -2.48929141E-05  -22.480252      -22.479540   

                  Total Heating applied to the system      =  19.999998   
                  Cooling at nodes with prescribed temp.   =-1.96207164E-06
                  Increase in the system internal energy   =  18.733543   
                  System heat balance=                     =  1.2664413   
                  For greater heat balance accuracy, reduce the solution convergence norm.


                  Nodal temperature results at time step =   239     (Time =     239.000    )
                  --------------------------------------------------------------------------------

                      Node   Temperature      Node   Temperature      Node   Temperature      Node   Temperature
                  ================================================================================================


                     Tmax  =  313.19261   
                     Tmin  =  290.14999