Heat transfer coefficient

dasch · August 16, 2011, 02:49

Hi

I'm trying to calculate the heat transfer coefficient from my CFD-Simulation. Can anybody tell me which formula I've to implement? I tried using the formula from OpenFoam's application wallHeatFlux, i.e. alphaEff*cp = alphat*cp+lambda divided by the height of the first cell normal to the surface. The units are matching (W/(m^2K)), but my results are way to high. Can anybody tell me where I can find theoretical results/formulas/literature for this topic?

Thanks a lot
Daniela

mettler · August 16, 2011, 09:02

what are you trying to simulate, and where are you trying to find the convective heat transfer coefficient?

dasch · August 16, 2011, 10:17

Hi

I'm using a simple 2D cylinder case to test my calculation of the heat transfer coefficient. Later it will be a cabin flow problem. The coefficient will be used to calibrate 1D simulations.

Daniela

mettler · August 16, 2011, 10:30

so, your hand calc is not matching your CFD result? And, it is a cylinder in cross flow?

dasch · August 17, 2011, 09:43

I wouldn't expect an exact match, but hand-calc gives 14 and my program gives 626. The difference is certainly to high.There is flow around the cylinder which was considered for the hand-calc.

August 16, 2011, 02:49	Heat transfer coefficient	#1
dasch New Member Daniela Join Date: Apr 2010 Posts: 7 Rep Power: 16	Hi I'm trying to calculate the heat transfer coefficient from my CFD-Simulation. Can anybody tell me which formula I've to implement? I tried using the formula from OpenFoam's application wallHeatFlux, i.e. alphaEffcp = alphatcp+lambda divided by the height of the first cell normal to the surface. The units are matching (W/(m^2K)), but my results are way to high. Can anybody tell me where I can find theoretical results/formulas/literature for this topic? Thanks a lot Daniela

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August 16, 2011, 09:02		#2
mettler Senior Member Andrew Join Date: Mar 2009 Location: Washington, DC Posts: 209 Rep Power: 18	what are you trying to simulate, and where are you trying to find the convective heat transfer coefficient?

August 16, 2011, 10:17		#3
dasch New Member Daniela Join Date: Apr 2010 Posts: 7 Rep Power: 16	Hi I'm using a simple 2D cylinder case to test my calculation of the heat transfer coefficient. Later it will be a cabin flow problem. The coefficient will be used to calibrate 1D simulations. Daniela

August 16, 2011, 10:30		#4
mettler Senior Member Andrew Join Date: Mar 2009 Location: Washington, DC Posts: 209 Rep Power: 18	so, your hand calc is not matching your CFD result? And, it is a cylinder in cross flow?

August 17, 2011, 09:43		#5
dasch New Member Daniela Join Date: Apr 2010 Posts: 7 Rep Power: 16	I wouldn't expect an exact match, but hand-calc gives 14 and my program gives 626. The difference is certainly to high.There is flow around the cylinder which was considered for the hand-calc.