Simple heat exchanger

strahinjailin · May 2, 2010, 04:16

Hello, I want to simulate simple countercurrent heat exchanger but I don't have idea how to define outlets? If I choose pressure outlet for the both outlets (hot and cold current) in the Physics values I have to specify Static temperature but I don't want to specify outlet temperatures - I want program to calculate those temperatures for me. And of course if a specify those temperatures in the outlet (pressure outlet-physics values) it gives me completely different solutions for every different temp. So what should I choose for the outlets? Thanks in advance, Strahinja

strahinjailin · May 2, 2010, 13:32

Ok, I get it out. I will explain if someone else have this problem. I just followed simulation developing and saw that between each iteration it says: Air outlet:reversed flow on 8 faces. Then I turned on mesh for scalar scene (temperature) and saw that exactly 8 faces have temp. that I specified under air outlet(pressure outlet)-physics values-static temperature. All other cells had good temperatures-totaly different than that specified for pressure outlet boundary (which I named air outlet). In other words, temperature that is specified for pressure outlet boundary only counts if reversed flow accour. Number of reversed flows decrease as number of iterations increase - cenvergence. So just wait for all curves to convergate, don't be unpatient as I was and all reversed flows will disappear.

May 2, 2010, 04:16	Simple heat exchanger	#1
strahinjailin New Member Strahinja Join Date: Apr 2010 Posts: 2 Rep Power: 0	Hello, I want to simulate simple countercurrent heat exchanger but I don't have idea how to define outlets? If I choose pressure outlet for the both outlets (hot and cold current) in the Physics values I have to specify Static temperature but I don't want to specify outlet temperatures - I want program to calculate those temperatures for me. And of course if a specify those temperatures in the outlet (pressure outlet-physics values) it gives me completely different solutions for every different temp. So what should I choose for the outlets? Thanks in advance, Strahinja

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Heat Exchanger Simulation	tightaznbreaka	FLUENT	0	March 18, 2010 15:45
Concentric tube heat exchanger (Air-Water)	Young	CFX	5	October 6, 2008 23:17
Heat Exchanger Efficiency	NTM	FLUENT	0	September 19, 2008 02:19
Pressure drop in a heat exchanger	Diana	FLUENT	5	December 13, 2007 09:33
Convective Heat Transfer - Heat Exchanger	Mark	CFX	6	November 15, 2004 15:55

May 2, 2010, 13:32		#2
strahinjailin New Member Strahinja Join Date: Apr 2010 Posts: 2 Rep Power: 0	Ok, I get it out. I will explain if someone else have this problem. I just followed simulation developing and saw that between each iteration it says: Air outlet:reversed flow on 8 faces. Then I turned on mesh for scalar scene (temperature) and saw that exactly 8 faces have temp. that I specified under air outlet(pressure outlet)-physics values-static temperature. All other cells had good temperatures-totaly different than that specified for pressure outlet boundary (which I named air outlet). In other words, temperature that is specified for pressure outlet boundary only counts if reversed flow accour. Number of reversed flows decrease as number of iterations increase - cenvergence. So just wait for all curves to convergate, don't be unpatient as I was and all reversed flows will disappear.