Critical Heat Flux of Multi-Nozzle Spray Cooling

Tiny nozzles are developed that are capable of creating the swirling flow necessary to generate a full cone spray. Eight miniature nozzles are embedded in a multi-nozzle plate used to generate a spray array for the cooling of high heat flux laser diodes. The target spray cooling area is a 1×2 cm2 flat surface of a copper heater plate. A closed loop spray cooling test setup is established. FC-87, FC-72 and methanol are used as the working fluids. Critical heat flux (CHF) is experimentally investigated at various spray saturation temperatures and nozzle pressure drops (from 0.690 bar to 3.10 bar). It is demonstrated that the spray cooler can reach the CHF levels up to 91.5 W/cm2 with FC-87 and 490 W/cm2 with methanol.