Determination of heat transfer and spray performances of isopropyl alcohol electrospray

Abstract

Reducing the size of electronics to micro or even nanoscale and increasing capacity leads to an increase in heat flux density. Various cooling methods fall short of removing heat flux from the surface. Electrospray is a novel method that provides high heat flux removal with a small surface area. In the previous studies; the mean particle velocity and the mean particle diameter of isopropyl alcohol electrospray based on electrospray modes have not been adequately studied. In this study, the electrospray and heat transfer characteristics of isopropyl alcohol were characterized for varying voltage ranges, in addition to alterations in volumetric flow rate, nozzle diameters, and nozzle lengths. The electrospray modes, mean particle diameter and velocity were determined by digital image processing of the resulting images from spray characteristic experiments, and the Enhancement Ratio (ER) values were calculated from the surface temperatures obtained in the heat transfer experiments. A minimum mean particle diameter of 31 µm was measured for the 12.70 mm length 26 G nozzle with a 100 µl/min flow rate and 12 kV DC voltage. Maximum mean particle velocity was found to be 7 m/s for a 6.35 mm long 20 G nozzle at 100 µl/min flow rate and an applied voltage of 16 kV. Maximum ER was obtained 1.75 for a 12.70 mm length 26 G nozzle, 100 µl/min flow rate and a voltage of 16 kV. ER values increased in almost all experimental conditions with the increasing voltage and volumetric flow rate.