Startup Time Reduction in an Electrohydrodynamically Enhanced Capillary Pumped Loop

Abstract

The capillary pumped loop (CPL) is a state-of-the-art technique for cooling of spacecraft and telecommunication devices. It provides substantially higher cooling capacity than most heat pipes, more flexibility of installation, and much greater distance of heat transport because of the small diameter of wickless transport lines. Major disadvantages of the CPL are long and complicated startup procedures and the possibility of deprime at high heat input or load variation. The present work was an experimental study to characterize the start-up process for an electrohydrodynamically (EHD) assisted CPL system. Startup is achieved by establishing stable differential pressure and average temperature at the evaporator wall. When an electric field is applied to the evaporator wick, the liquid-vapor separation, the EHD pumping, and the instability-induced Maxwell stresses collectively contribute to reduce the startup time, as well as provide substantial improvement in CPL thermal performance. The experimental data in the present study show that at a power level of 10 W, the EHD can reduce the startup time by as much as 50% at an applied voltage of 10 kV. A similar trend is observed at power levels of 20 and 50 W.