Hello i have a problem with a simulation I was running. I am modeling melting of a salt in a cylinder (a transient problem). The cylinder has a wall thickness. The outside wall of the cylinder has a convection condition with a fluid of temperature ~590K and heat transfer coeff of 19-35 w/m2-k. The inside of the cylinder has salt and air. the salt melts at ~579K. the initial temp is 578K. The cylinder wall material is aluminum. The inside wall has a shadow, as an interface, which is coupled to the inside wall.
I have done 7 cases of cylinders with different dimensions for the same case as above except with an isothermal boundary condition on the outside wall, instead of convection. All the isothermal cases computed fine. I opened the isothermal case file and changed the BC constant temperature to convection with constant h and free stream temperature, and reinitialized.
When I ran the simulation, the energy equation residual was constant line, as with all the other residuals. This behavior lasted during the entire computation. at time = 60 seconds, I checked the static temperature contour; it showed that the highest temperature in the system was 579K (this should be near 590K, especially since a metal with high thermal conductivity is used). I created a integral total surface heat flux monitor at the inside wall of the cylinder. This monitor stated that the heat flux rose from 3.26 to 3.44 and then stayed constant at 3.44 for rest of the computation, which doesn't make sense. http://www.trainingintambaram.in/ccna-training-in-chennai.html#