Heat Transfer Investigation Of Aluminum Oxide Nanofluids In Heat Exchangers

Abstract

An experimental study was conducted to investigate the use of waterbased aluminum oxide nanofluids in enhancing the heat transfer performance of heat exchangers. Two types of heat exchangers were studied: a blocktype heat exchanger for an electronic system cooling, and a radiator-type heat exchanger simulating an automobile cooling system. Tests conducted on the block heat exchanger used 20 nm alumina particles at a concentration of 5% by mass (1.3% by volume), while tests conducted on the radiator-type heat exchanger used 50 nm alumina particles at a concentration of 3% by mass (0.8% by volume). Tests conducted on the electronic heat sink system show an average enhancement of about 20% in heat transfer coefficient, while tests conducted on the radiator-type heat exchanger show a substantial enhancement in heat exchanger effectiveness that reaches almost 49%. Results demonstrate that the application of nanofluids in low concentrations is sufficient to cause a considerable improvement in the system‘s thermal performance. Results also show that the increase in bulk flow heat transfer coefficient happens at the expense of the increase in fluid pumping power caused by the increase in fluid viscosity.