Startup time reduction in an electrohydrodynamically enhanced capillary pumped loop

The capillary pumped loop (CPL) is a state-of-the-art technique for cooling of spacecraft and telecommunication devices. It provides substantially hig her 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 c omplicated startup procedures and the possibility of deprime at high heat i nput or load variation, The present work was an experimental study to chara cterize the start-up process for an electrohydrodynamically (EHD) assisted CPL system. Startup is achieved by establishing stable differential pressur e and average temperature at the evaporator wall. When an electric field is applied to the evaporator wick, the liquid-vapor separation, the EHD pumpi ng, 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 l evels of 20 and 50 W.