3 Replies Latest reply on Feb 23, 2012 12:13 PM by Gabe Ahseln

    Thermal Analysis Discrepancy

    Gabe Ahseln

      Hello,

       

      A premptive thank you for anyone with information on this anomaly I have noticed in SW Simulation. I have an assembly with a sensor defined in SW determining the average temperature of a flat plate exchanger exposed to natural convection + radiation heat transfer. I have noticed that if I run the same analysis but change the orientation of the assembly (top view vs bottom view) the values I get for the average temperature change! If I repeat the analysis in the same orientation I get the same results, but as soon as I change the view and recalculate, the results change.

       

      Any input is much appreciated!

        • Re: Thermal Analysis Discrepancy
          David Maxham

          Gabe - sounds like one strange "view factor" to me.    Sorry, I don't have a clue - but maybe if you tried turning off radiation temporarily and re-running the model to see if you still get the same effect from a change in orientation?

           

          Dave

          • Re: Thermal Analysis Discrepancy
            Gabe Ahseln

            After doing some more troubleshooting, I found that even if I don't change the view orientation, Solidworks gives me a range of solutions for the average temperature of the exchanger from 30.0-31.4. It seems like Solidworks is performing itterations and locking onto different solutions each time.

             

            Is this a possible culprit? Is there any way to change the itteration definitions in Solidworks?

             

            Not to get sidetracked from the original issue, but I have an additional queurery about heat flux in SW. It appears as though Solidworks dissobeyes Kirchoff's laws! If I probe the average heat flux in the Y-direction over a heat collecting surface (constant temp boundary) and multiply by that area to get a total heat flux value, and then if I look at the total heat flux through the peice in the middle (refer to picture) they are different! Additionally, if I look at the total heat flux through the top plate and compare it to the flux through the bottom plate, they are also different!

            Untitled.jpg

            • Re: Thermal Analysis Discrepancy
              Gabe Ahseln

              If others run into this problem, I found that making the mesh significantly smaller helped resolve the issues.