Abstract
A closed-loop impingement spray cooling system which is capable of cooling a 1kW 6U electronic test card has been developed. The heated surface area is 13.5 × 15.1 cm 2 . R134a was used as working fluid in a modified refrigeration closed-loop cycle. Four vapor assisted nozzles are implemented to generate spray to cover a large ratio of the heated area of the card. The effects of mass flow rate and spray saturation temperature on thermal performance are investigated experimentally in this study. Experimental results are promising with a stable average temperature of around 25 C being maintained on the heated surface with small temperature variation on the heated surface at suitable operating conditions. It is found that cooling performance has been improved with increasing of mass flow rate and spray saturation temperature.