Transient Thermal Analysis in Ansys (APDL)

[grey]

Hi,

I have to model a transient thermal problem in Ansys. I just need an outline of how I should proceed.

The Problem:
I am trying to model the cooling of a solar collector reciever tube from 150 degree celsius to ambient.

My attempts have involved the following:
1. Initial condition of 423 at the inner dia of the circle
2. Convection Boundary condition (film coefficient of 25 and bulk temp of 298) at the outer dia of the circle

It is not displaying the results properly (or I am reading them wrong). It shows the entire system at 298 apparently all the time.

Are these conditions sufficient to constitute a solution in Ansys? What else am i doing wrong or I need to do?

Thanks in advance.

 

[Unrest]

Not sure about ANSYS specifically, but are you sure the results are unrealistic? Is the time between steps smaller than your estimated time to reach equilibrium?

Have you specified heat capacity of the tube? With that zero it'll probably reach equilibrium instantly.

Try putting a different bulk temperature somewhere and see that it produces a temperature gradient between then. That should confirm that it's at least doing something! And suggest that it's cooled too quickly.

 

[Mech_Engineer]

Did you set an initial condition for the starting temperature of the parts? Default starting temperature is 298 or so, this might be your problem...