Flow simulation - Natural convection & conjugate heat transfer problem
The study that I'm working on has a chamber with some critical process components and an evaporator that is part of a refrigeration system. The purpose of the study is to determine the flow direction inside the chamber as a result of natural convection and introduce vanes/ ducts to improve the direction of the flow to cool some critical components inside the chamber. The evaporator is assumed to be isotropic and represented as a rectangular block at 248 K. The initial temperature of this solid domain is set to 248 K. Also, a specified temperature of 248 K is defined for the evaporator under its general boundary condition.
The density of the fluid domain inside the chamber is set to behave as an ideal gas, to account for changing density of air. The chamber and other components are initially at 300 K, ambient. The objective is to determine how the cold and denser air around the evaporator pushes warmer and lighter air inside the chamber through natural convection.
The issue is, following RUN, the evaporator is no longer at a steady temperature of 248 K. How to define a component to remain at a specified temperature throughout the analysis?
As can be seen in the picture above, the simulation quickly assumes that everything is near ambient (the min and max temperatures are near ambient). Instead the temperature of the evaporator should remain at 248 K throughout. If the boundary conditions have been assigned incorrectly, please do advise.