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-   -   Heat Exchanger...TWO (http://www.cfd-online.com/Forums/cfx/21424-heat-exchanger-two.html)

Walid July 9, 2005 16:47

Heat Exchanger...TWO
 
Hi,

I am a new CFX user and the only version that I can use is CFX 5.5.1. I have posted a question on this forum last month with title: Heat exchanger. I received a number of replies but none of them seems to answer the question.

I would be grateful if any one has a previous experience in simulation of heat exchanger condenser can help me on this. Please, see to the previous question on Wed, 22 Jun 2005, 5:09 p.m. for details.

Below I show the reference case and CFX result for a heat exchanger tube;

Design case as reference;

Tube lenght is 8 m Tin=70'C Tout=85'C Tube Diameter is .02 m Wall Temperature (fixed) is 90'C

CFX result;

Tube lenght is 8 m Tin=70'C Tout=90'C Tube Diameter is .02 m Wall Temperature (fixed) is 90'C

I noticed the fluid reaches the wall temperature before passing 1/3 of tube length which contradicts the design data.

Is this reasonable result from CFX? Or I have made a mistake somewhere?

I appreciate any help…

Glenn Horrocks July 10, 2005 18:59

Re: Heat Exchanger...TWO
 
Hi,

Sounds like you need to do some reading into wall heat transfer modelling. Have a look at some heat transfer validation studies (the CFX Community has some available for download) and textbooks - Turbulence Modelling for CFD by Wilcox is a good one.

Glenn Horrocks

Walid July 11, 2005 19:04

Re: Heat Exchanger...TWO
 
Dear Glenn Horrocks,

Thank you for your advice and for previous reply, I have already covered the topic theoretically but the simulation results are a bit weird. I will try to find some previous studies.

Thnaks

Walid


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