Capillary pumped-loop thermal performance improvement with electrohydrodynamic technique

The capillary pumped loop (CPL) is a state-of-the-art technology for cooling spacecraft and telecommunication devices. It is a two-phase heat-transport device in which the driving force is provided by the capillary action of the wick material in the evaporator. Compared to the widely used heat pipes, it provides a higher heat-transport capacity, more flexibility of installation, and greater heat-transport distance because of wickless transport lines and the absence of liquid and vapor counterflowing, The major disadvantages of the CPL are long and complicated startup procedures and the possibility of deprime at high heat input and large load variations. This paper investigates the liquid-vapor separation and thermal management with the electrohydrodynamic (EHD) technique for an EHD-assisted CPL using R-134a as the working fluid, An experimental investigation, along with a mechanism analysis, was employed to evaluate the potential of the EHD technique for thermal performance improvement of CPL systems, Experimental results showed that enhancements, up to three times, could be obtained in heal-transfer coefficients by applying an electric field at different heat load levels. The depriming conditions of a capillary pump can also be prevented with the EHD technique.