Actively Pumped Two-Phase Loop for Spray Cooling

Abstract

A new closed two-phase loop that combines with a large area spray cooling unit for the cooling of high heat-flux power sources is developed. The fluid circulation is sustained by a magnetic gear pump operating with an ejector unit. The motive flow of the ejector shares the pumping liquid flow with the multinozzle spray. With the assistance of the ejector, the maximum spray pressure drop across the nozzle can be enhanced by at least 0.56 bar at critical heat fluxes (CHF). This increases CHF of the spray cooling by up to 16%. More importantly, the use of the ejector prevents the uncondensed vapor from entering the magnetic gear pump and stabilizes the circulation of the two-phase flow. During the experiment, a multinozzle assembly with 48 miniature nozzles is employed. The target spray cooling area is 19.3 cm 2 . FC-72 and water are used as the working fluid. The present design concept can be applied to cooling systems operating in the aerospace environment.