I am trying to simulate the sealed aluminium enclosure with small block of steel inside exposed to 40 C ambient. Inner volume is filled with air (still air).

Goal: to know how long the steel inside the sealed enclosure takes to come to equilibrium (i mean =40 C)

My conditions:

External study

Time dependent on and also gravity

Fluid subdomain air

I ran the analysis for transient state of 180 minutes. it shows it takes 120 min to reach 37 C and 240 min to reach 40C . these results are not coinciding with my experiment results which says with 45 minutes all should be in equilibrium

I want to know is there anything wrong with my setup or ????

any other way to simulate