Heat transfer Simulation in boiler

[Anonymous]

Hi everybody,

I'm trying to simulate heat transfer in boiler by CFD (bellow image). However, it does not work. Temperature of all positionS is 800oC. I wonder what's wrong with models or boundary conditions? Please help me resolve it.

Thank all you so much. 

Calculation file: http://www.mediafire.com/?p5gt77ar3em9cel

Result:

[Anonymous]

Hi everybody,

I'm trying to simulate heat transfer in boiler by CFD (bellow image). However, it does not work. Temperature of all positionS is 800oC. I wonder what's wrong with models or boundary conditions? Please help me resolve it.

Thank all you so much. 

Calculation file: http://www.mediafire.com/?p5gt77ar3em9cel

Result:

[ilyas_drawbridge]

Hi, it seems that your thermal BC might be inadequate. You only have 800C air coming into the domain, just that. If run till steady state, everything will ultimately be 800C. What I would do is apply a film coefficient BC at the outer walls of your parts to simulate some cooling due to convection of ambient air. Unless... you are expecting heat to transform into some other form of energy, then perhaps a -ve heat generation might work. What is the rubber doing there anyway?

Regards

Ilyas

[ilyas_drawbridge]

Hi, it seems that your thermal BC might be inadequate. You only have 800C air coming into the domain, just that. If run till steady state, everything will ultimately be 800C. What I would do is apply a film coefficient BC at the outer walls of your parts to simulate some cooling due to convection of ambient air. Unless... you are expecting heat to transform into some other form of energy, then perhaps a -ve heat generation might work. What is the rubber doing there anyway?

Regards

Ilyas

[apolo_vanderberg · Accepted solution]

Ilyas is correct here. To do a thermal model we will need at least 2 thermal boundary conditions.

You have an inlet temperature, we would need something else (Film Coefficient on exterior to represent how the model can lose heat to the surroundings that we do not have modeled; Neg Heat Generation to represent heat conversion of some sort; or a second flow domain that would have its own temperature inlet).

Apolo

[apolo_vanderberg · Accepted solution]

Ilyas is correct here. To do a thermal model we will need at least 2 thermal boundary conditions.

You have an inlet temperature, we would need something else (Film Coefficient on exterior to represent how the model can lose heat to the surroundings that we do not have modeled; Neg Heat Generation to represent heat conversion of some sort; or a second flow domain that would have its own temperature inlet).

Apolo