1 Reply Latest reply on Jun 17, 2015 12:44 PM by Shivani Patel

    Multi layer solid thermal conduction in flow simulation

    Philip Wysocki

      Hi All,

       

      I am having issues meshing and understanding how thermal conduction works in SOLIDWORKS.

      In the sketch below I have a volumetric heat source applied to two copper components at around 9W each. I have volumetric temperature goals for the copper components and surface temperature goals for other surfaces.

      To reduce the computation time I have created a local initial mesh around the 1mm air gap and the nylon, copper, resin and aluminium components, as shown below.

       

      The meshing of the air gap and the horizontal nylon component is fine however the vertical nylon parts, the copper, resin and aluminium are not meshing correctly.

      If I reduce the mesh size for the entire part it will take too long to compute.

       

      I have never used contact resistance so the question is am I supposed to have contact resistances between all of the components for the meshing and thermal conduction to be calculated correctly? Doesn't it automatically take this into account with the mating of different components?

      As the resin layer is not uniform I can't simply create a contact resistance between the copper and aluminium, as a result I have to model it, how do I get it to mesh correctly?

       

      For the top air gap (0.15mm), it is very difficult to mesh this without the computational time being drastic. Do I add a contact resistance between the two surface which represents the 0.15mm air gap to speed things up?

       

      I have never used contact resistances before, when adding one between two components do you apply different contact resistances at the individual component surface (eg: copper, ground, 1.5um surface area and another for the aluminium)?

       

      Is there anywhere that I can find out the contact resistance of copper to nylon, nylon to aluminium, copper the resin, etc?

       

      With SOLIDWORKS thermal conduction between multi-layered solid components do you have to use contact resistances? Is there another alternative

       

      Regards,
      Phil

        • Re: Multi layer solid thermal conduction in flow simulation
          Shivani Patel

          No, you don't have to have contact resistance applied everywhere. The contact resistance is there to represent something that isn't modeled in or represented by the fluid flow. Like a layer of paint, or an air gap within the model while "exclude cavities without flow conditions" is checked.

           

          You could try another finer local initial mesh on that resin layer. I'm sure that will be computationally intensive. That is your only option if you do not simplify it using contact resistance. Can you create split faces on one model and apply different resin thicknesses via contact resistance that way?

           

          Sure, you can absolutely apply a contact resistance instead of meshing the air gap.

           

          Like I said a minute ago, contact resistance is like representing a layer of paint. If the air was paint, you would only apply the contact resistance to one part. If you applied it to both you would double the resistance accidentally.

           

          I am not sure of a database with resistances, sorry. You could convert thermal conductivity into thermal resistance using R = t/k, where t is thickness and k is thermal conductivity.

           

          I have confused myself by what you mean by multi-layered solid components, so I don't have a tip for you.