The Enhancement Ratio of Corresponding Convection Heat Transfer Coefficient Using Electrospray Evaporative Cooling System

The thermal management of microelectronics demands high heat flux removal solutions due to a rapid increase in component and heat flux densities generated from the integrated circuits (ICs) per unit area. Electrospray evaporative cooling (ESEC), which combines two-phase cooling and an electrospray technique, is presented to be the thermal management solution for next generation microelectronics in order to overcome the heat transfer cooling limits for traditional cooling technologies. In this paper, the enhancement ratio of the corresponding convection heat transfer coefficients and heat removal ability of the ESEC system are investigated in terms of the number of spraying nozzles, total volume flow rates of ethanol alcohol, DC potentials, and gaps between the spraying nozzle and a thermal exchange surface. As the results show, thermal images have indicated the cooling ability of the ESEC system. Additionally, the electrospray modes induced by the distribution of electrostatic fields have a great impact on the heat transfer performance of the ESEC system. The maximum enhancement ratio, 1.61, and heat removal ratio, 61%, has been achieved by the 4-nozzle array. The corresponding calculated heat flux difference and convection heat transfer coefficient were approximately 123.19 W/cm² and 3.99 W/cm²K, respectively. Furthermore, the results also indicate that increase the number of the spraying nozzle and decrease the flow rate per nozzle is regarded as the effective way of improving the heat transfer performance of ESEC devices. A simple regression curve for the relationship between the heat removal ratio and enhancement ratio was also addressed.