2 Replies Latest reply on Mar 19, 2013 3:12 PM by Chuck Webb

    Unexpected Thermal Results

    Chuck Webb
    Chuck Webb Mar 18, 2013 10:48 PM

      system is a follows:

       

      Electrical components producing X Watts are bonded to a thermal pad which is bonded to a heat sink which is bonded to a chassis and part of the chassis has a known temp.

       

      I ran 2 simulations. One used a thermal pad with a conductance of 6 W/m-K and one with 3 W/m-K.

       

      I am getting consistantly lower component temperatures with the less conductive thermal pad! (45deg vs 44deg).

       

      Anyone know why this might be?

       

      Thank you

        • Re: Unexpected Thermal Results
          Jared Conway
          Jared Conway Mar 19, 2013 3:30 AM (in response to Chuck Webb)

          the only place in your model that the temperature can leave is through a face that you've set the temperature? or do you have convection applied to the model somewhere? remember that if you don't apply a bc to a non-conduction face, it is assumed insulated.

           

          have you created a simple stackup example of blocks to check that its not your model and/or the software (depending on what the outcome is)

          • Re: Unexpected Thermal Results
            Chuck Webb
            Chuck Webb Mar 19, 2013 3:12 PM (in response to Chuck Webb)

            I had several issues that I corrected to make the study more accurate.

            The main issue was that although I had the right material selected for the model, somehow the material of the lower performance thermal pad was changed in the thermal study to Aluminum instead of thermal pad material. That will definitely improve the heat transfer!