After an unknown number of trials on thermal analysis I gave up trying and it's time to ask the experts in this field

I have a pebble bed heater which heats the air before entering a wind tunnel.

I'm not so familiar with the thermal analysis in computer software but I want to do it with solid works to compare the results with our results by hand calculation for our senior project.

We have a very high temperature input in the heater but whenever I put the value I get a constant temperature all over the parts it should be gradient with the difference of the heat conductivity of the materials.

Maybe I'm doing it wrong but I need help on how to do it correctly. We have a temperature of 1100 K and the air should reach that value within 2 hours of heating. I couldn't find a time input. I keep getting same color all over the heater and the temperature should be less than 300 K on the shell

I have defined new materials in the library and I have only inserted the thermal information not all. To make sure it is correct. What inputs are required to add other than Thermal expansion coefficient, thermal conductivity and specific heat???

This is a capture screen of the heater that I want to do the analysis with.

Each cylinder has a different kind of material.

Also I would like to know about the gap inside the cylinder if soildworks consider it as air or vacuum ?

your help is appreciated

in thermal analysis, the software doesn't know anything about the fluid other than what you tell it by applying convection coefficients

in a flow analysis, the air is handled through CFD

this is going to be a really hard problem to solve in thermal, do you have access to flow?

my suggestion for either tool is to start with a really simple example that you can validate, make it work in the software then start small with your big problem and go from there.