heat flux at fluid solid interface

Studentdrak · January 27, 2012, 05:32

Hi

I am simulating a heat transfer problem where, one side of the solid domain has a wall heat flux in small patches(not all the wall on one side) and the other side of the solid domain has air flowing over it.

How does cfx calculate the heat flux at the fluid solid interface?

pl. do help asap

Regards

ghorrocks · January 27, 2012, 07:30

Yes, definitely. Look for the wall heat flux variable.

Studentdrak · January 27, 2012, 09:14

Hi ghorrocks

thanks.

I am running cases with finer and finer meshes (for grid independent study), but I dont see any considerable change in wall heat flux( number of nodes have been increased from 7,14,28,56 (for 6mm air gap)

and i want to know how does this wall heat flux(or local heat flux) and local delta Temperature vary. Is there a way to show these from results file in cfxpost?

Regards

Studentdrak · January 27, 2012, 10:33

Hi herewith i have attached the temperature contour. but the wall heat flux has almost the same value for all these cases. any suggestions pl.

singer1812 · January 27, 2012, 12:12

Why do you think that the wall heat flux changes?

If you are running a ss analysis, with constant heat coming in one side of the solid, air flow on another side and I assume adiabatic on the other sides, the heat flux will remain constant (qin=qout).

Mesh density will not alter this, energy should still balance out if convergence is achieved.

Studentdrak · January 30, 2012, 11:55

Thank u singer

Studentdrak · January 30, 2012, 12:05

Hello

I dont find any variation with respect to the mesh refinement.

Temperature is varying up to 2deg(at hot spots) with increasing the nodes 4 times the earlier coarser grid(step by step)

Is there a problem?

I use K epsilon model(scalable wall function)

pl. do suggest

January 27, 2012, 05:32	heat flux at fluid solid interface	#1
Studentdrak Member Join Date: Aug 2011 Posts: 53 Rep Power: 15	Hi I am simulating a heat transfer problem where, one side of the solid domain has a wall heat flux in small patches(not all the wall on one side) and the other side of the solid domain has air flowing over it. How does cfx calculate the heat flux at the fluid solid interface? pl. do help asap Regards

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January 27, 2012, 07:30		#2
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,854 Rep Power: 144	Yes, definitely. Look for the wall heat flux variable.

January 27, 2012, 09:14		#3
Studentdrak Member Join Date: Aug 2011 Posts: 53 Rep Power: 15	Hi ghorrocks thanks. I am running cases with finer and finer meshes (for grid independent study), but I dont see any considerable change in wall heat flux( number of nodes have been increased from 7,14,28,56 (for 6mm air gap) and i want to know how does this wall heat flux(or local heat flux) and local delta Temperature vary. Is there a way to show these from results file in cfxpost? Regards

January 27, 2012, 12:12		#5
singer1812 Senior Member Edmund Singer P.E. Join Date: Aug 2010 Location: Minneapolis, MN Posts: 511 Rep Power: 21	Why do you think that the wall heat flux changes? If you are running a ss analysis, with constant heat coming in one side of the solid, air flow on another side and I assume adiabatic on the other sides, the heat flux will remain constant (qin=qout). Mesh density will not alter this, energy should still balance out if convergence is achieved.

January 30, 2012, 11:55		#6
Studentdrak Member Join Date: Aug 2011 Posts: 53 Rep Power: 15	Thank u singer

January 30, 2012, 12:05		#7
Studentdrak Member Join Date: Aug 2011 Posts: 53 Rep Power: 15	Hello I dont find any variation with respect to the mesh refinement. Temperature is varying up to 2deg(at hot spots) with increasing the nodes 4 times the earlier coarser grid(step by step) Is there a problem? I use K epsilon model(scalable wall function) pl. do suggest