2 Replies Latest reply on May 24, 2016 6:42 PM by John Highet

    Help with Flow Simulation in Simple Enclosure

    John Highet
    John Highet May 24, 2016 11:24 AM

      Hello,

      I'm trying to run what I thought would be a simple natural convection flow simulation of an enclosure with a 150W node inside.  All I want to find is max temperature of the internal air and how it flows through the enclosure.  I am new to Flow, so I've only done a couple of the tutorials to learn the basics, but I must have missed something because my results do not seem right.  I'm only getting a temperature rise of a couple degrees inside the enclosure.  Also, inlets are supposed to be the lower, rear louvers and outlets are supposed to be the front lid overhang vents.  When I do a dynamic trajectory, the air is coming in through the lid vents.  ?!?!?!  I've attached my Pack&Go, any help, tips and tricks would be greatly appreciated.

       

      Thanks,

      John

        • Re: Help with Flow Simulation in Simple Enclosure
          Amit Katz
          Amit Katz May 24, 2016 11:44 AM (in response to John Highet)

          Look at your mesh resolution in the inlet, it's awful:

          Capture.PNG

          You've got half a cell covering the entire length of the open area.

           

          I recommend you start with a 2D analysis. It will allow you to greatly increase the mesh resolution that you need for these relatively small inlets. It's not a very realistic model, but it should give you some idea of how you need to structure the enclosure to get the best flow around your hot components.

          I would also recommend modeling your mounting fixture. Right now your hot box is just floating in the middle of this enclosure, not very realistic.

            • Re: Help with Flow Simulation in Simple Enclosure
              John Highet
              John Highet May 24, 2016 6:42 PM (in response to Amit Katz)

              Thanks for the reply Amit.  I'm not sure how to do a 2D analysis, but I did find how to refine my local meshes for my inlet and outlet lids and am running another sim now.  I was also wondering about my wall conditions. I'm just using wall temperature because I'm not sure how to input the correct heat transfer coefficient (the tutorials always have a number to put in there, but don't tell you where it comes from) - do I need to calc that?

               

              I was trying for super-simple, but as you suggested I did add the mounting bracket for my node ("hot box").

               

              I'll upload again after running with the refined mesh.

               

              Thanks again,

              John