Characterization of spray atomization and heat transfer for a swirl nozzle

Abstract

Spray cooling, a high heat flux thermal management, has received great attention from modern industrial and technological applications, such as power electronics, high-power lasers, and conversion systems etc. The focus of the present work is to investigate the spray characteristics and heat transfer of a swirl nozzle under a low pressure drop range. An open loop spray cooling system is developed to examine the heat transfer performance of the swirl nozzle by considering the effects of nozzle pressure drop, impinged spray height. A Phase Doppler Anemometry (PDA) system is applied to characterize the droplet Sauter Mean diameter, droplet velocity, spray angle, and spray pattern. It is found that the swirl nozzle under lower pressure drop helps to generate a full cone spray with a smaller spray angle, while the higher pressure drop produces better atomization quality. The heat transfer experimental results indicate that the droplet impingement is the primary cooling mechanism in the nonboiling regime of spray cooling, and increasing the pressure drop generally improves the heat transfer performance.