Investigation on the influence of lubricant oil to the spray cooling system based on refrigerant cycle

Abstract

The spray cooling system based on refrigeration cycle is considered as an effective way for heat dissipation, however, its performance will be effected by lubricant oil of the compressor. In this paper, a test bench is built to study the influence of the lubricant oil RL68H on the heat transfer performance is experimentally investigated at different oil concentration, heat flux and mass flow rate. The results show that the heat transfer coefficient (HTC) decreases from 18000W/(m2·°C) to 8000W/(m2·°C) with oil concentration rising from 0.00% to 5.99%, when the input power and the mass flow rate are fixed at 60W and 2kg/h, respectively. We also studied the lubricant oil influence in the conditions of when input power is fixed and the mass flow rate is variable. The experimental results showed that lubricant oil had great influence on the spray cooling system based on refrigerant cycle, in order to improve the heat transfer performance, the lubricant oil concentration in the system should be reduced as much as possible.