Wall's temperature is not enough.
 

Hi,

I'm trying to simulate the deformation and the stress of a duct but I have a few problems. The duct its used to heat a melted salts for a heat exchanger. For the heating I've used a methane-air combustion and I get the desired temperature, this is 1800ºC.

I want to simulate that the duct itself its inside the melted salt deposit. How could I do in the CFX to simulate the static temperature of the salts?

I have tried using in the duct's wall the Heat Flux, the static temperature, and the Heat Transfer Coefficient. Sadly, I havent the true Coefficient, so I'm trying different coefficients, until I get a logic temperature.

My problem apart from not knowing the real coefficient of the salts, its that I dont get a good temperature for my duct. I dont understand how having a combustion of 1800ºC in steady state and an involving salts at 380ºC, the duct just rise the temperature to 470ºC. The duct is of structural steel.

Thanks!