Negative heat flow and radiation in steady state thermal

    • Csongor Varadi

      Dear ANSYS users,


      I'm trying to simulate the cooling of an aluminium block inside a vacuum chamber by using a meander fixed to a copper plate (See screenshots below). For boundary conditions I have set a heat flow on the inside of the piping with -112.5 W, and a radiation on the inside enclosure of the vacuum chamber with an ambient temperature of 20°C and an emissivity of 0.8. Initial temperature is set to 20°C. The outer surface of the chamber is set to a temperature of 20°C.

      If I set the heat flow to be positive (i.e. heating) the simulation converges just fine, however if I use a negative heat load the simulation fails to converge, or does so extremely slowly. The problem might lie with the radiation boundary condition, however I am somewhat stuck and can't progress with the issue, so any help would be appreciated. 




    • Karthik R


      What is the direction of heat flow in your problem? A positive value indicates heat flow into the node, while a negative value indicates out of the node.

      Have you tried to isolate the problem by switching off the radiation heat transfer? 

      Also, could you please help us understand your problem a little better? What are you looking to model?

      Thank you.

      Best Regards,


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