ENTROPY GENERATION ON A CROSSFLOW HEAT EXCHANGER INCLUDING THREE GAS STREAMS WITH DIFFERENT ARRANGEMENTS AND THE EFFECT OF LONGITUDINAL WALL CONDUCTION

Abstract

This study investigates the entropy generation on a crossflow heat exchanger including three gas streams with three different arrangements. Using the numerical method, this study calculates individually the exit mean temperature of each gas stream in different arrangements, and then computes the number of entropy-generation units of each arrangement. Results indicate that there is a maximum entropy generation for each arrangement along with the increase in number of transfer units (NTU). Comparing the three arrangements shows that the entropy generation of the third arrangement is the lowest, because this arrangement transfers heat across a smaller temperature difference. In addition, this study examines the effect of longitudinal wall conduction on the entropy generation in each arrangement. The largest effect on entropy generation is found in the third arrangement.