Annals of the Assembly for International Heat Transfer Conference 13

ISBN 1-56700-225-0 / CD 1-56700-226-9

Year 2006

R. K. Shah
Subros Limited, Noida, India

T. Skiepko
Bialystok Technical University, Bialystok, Poland

In this paper, a methodology is presented for the analysis of the coupled behavior related to the heat exchanger effectiveness and irreversibility due to heat transfer at finite temperature difference. The approach is based on decomposition of complex flow arrangements into elemental sub-exchangers of simple configurations - parallelflow and counterflow. It is shown here that due to variable inlet temperatures in the sub-exchangers (except for one having fluid entrance), their irreversibility behavior on NTU is also strongly dependent on the complex flow arrangement when compared to such behavior of the same sub-exchangers operating standalone. The irreversibility analysis can be correctly performed by taking into account individual sub-exchanger flow arrangements, how the sub-exchangers are connected and what are consequences of such coupling for the irreversibility and effectiveness behavior. We have analyzed and explained here the complex effectiveness -irreversibility behavior for a specific example of four 3 pass - 3 pass plate heat exchangers (PHEs) having overall parallelflow and counterflow arrangements with individual passes in parallelflow and counterflow. We have found that the PHE having overall parallelflow and individual passes in counterflow has peculiar performance behavior with zero or negligible contribution of second and third passes in exchanger effectiveness and performance. Also, based on the results presented here for four 3 pass - 3 pass PHEs having R₁ approximately about 2 or less, we found that there is no significant gain in performance for NTU₁ > 2 for any of four PHE flow arrangements; and for R₁ ≥ 2, NTU₁ should be even less than 2.

HEX-17 pages DOI: 10.1615/IHTC13.p18.170 Download article

Article price - $35.00

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