Hi to all!

I have some questions regarding the heat transfer analysis of a fuel tank using CFDesign 5.0. The tank is closed and empty, only air with initial 20 degree Celsius temperature at atmospheric pressure is inside the tank. The tank is exposed to a 160 degree Celsius oven for up to 30 minutes during a tank painting process. We want to determine the internal air temperature of the tank after that 30 minutes time period.

1. Is there any way to determine the final air temperature inside the tank by specifying the length of time of heat application?

2. In the CFDesign Domain, we set the outer tank surfaces at ambient oven temperature (200 deg C). Is it also necessary to set the initial temperature (20 deg C) of the air inside the tank? If necessary, where to specify the internal ambient temperature of the air? We only specify the initial air temperature at the CONTROL-INITIALIZATION at the CFDesign Solver.

3. What are the other setting variables that we have to specify in the solver for this kind of analysis?

Usually, these cooling/heating transient heat transfer problems can be described with an exponential law and a time constant (dependent among other things on the htc, tank material etc). To do some preliminary hand calculations, you need to use correlations for the htcs inside and outside of the tank. Inside you can use correlations for natural convection. Outside natural or forced convection, depending the oven environment. This will give an approximate answer which can be compared with the CFD.