Experimental Study of a Liquid-to-Air Heat exchanger Using Copper Woven Wire Mesh

Abstract

Liquid-to-air cross-flow heat exchangers have a low heat transfer coeffi-cient on the gas side due to poor thermal characteristics of air. One of the conventional solutions of this problem is to attach extended surfaces on the gas side, thus increasing the surface area of heat to transfer by convection. In this study, experiments were carried out to evaluate the thermal and hy-draulic performance of four modules of cross flow heat exchangers. One is bare copper tubes and three wire mesh heat exchangers of different mesh spacing. Hot distilled water was pumped into the copper tubes at a constant flow rate of 9 l/min and inlet temperature of 80oC. The heat exchanger was subjected to external cross airflow inside an air duct of 20 cm x 20 cm cross-sectional area with an average air velocity of 2.8 m/s up to 14.9 m/s. Results showed an enhancement of Nusselt number for all wire mesh modules that is an increase of the volumetric heat transfer coefficient of up to 113.9% among the three tested modules, compared to the bare module. The significance of this study is to use reasonably-priced wire mesh and maintain enhancement of the rate of heat transfer.