Multi-nozzle Closed Loop Spray Cooling Systems in Electronics Cooling

Abstract

This study presents two refrigerant closed loop spray cooling systems for two specific electronic cooling applications. A small system using a 3 × 2 nozzle array is developed to investigate the spray cooling performance on a concentrated heat source (2 × 1 cm2) with a high heat flux. A big system uses a 9 × 6 nozzle array to cool a 6U card area (23.3 × 16 cm2) with a moderate uniform heat flux. The experimented flow rate in the small system is maintained at 7.8∼8.1 g/s corresponding to a spray mass flux of 3.9∼4.05 g/cm2⋅s on the concentrated heat source, and the studied flow rates in the big system are monitored at 113 ± 4 g/s corresponding to a spray mass flux of 0.30 g/cm2⋅s on the 6U card surface area. The results show that the small system with a much higher spray mass flux can perform a spray cooling curve with a wide heat flux range. The big system with much less spray mass flux has performed a slightly better heat transfer coefficient due to its much better evaporation efficiency at the same degree of surface superheat.