以R22为冷却剂的闭式循环相变喷雾冷却实验研究

Experiment on Phase Change Spray Cooling of Closed Cycle with R22

为了获得相变喷雾冷却特性,设计并搭建了以R22为冷却剂的闭式循环喷雾冷却实验平台,研究了制冷剂R22的相变喷雾冷却性能。实验在喷雾高度为22 mm、喷雾腔压力维持在0.34MPa、喷嘴入口温度保持在-3℃的条件下进行。实验结果表明:当维持喷嘴入口压力为定值时,随着加热功率的增大,热流密度增大,表面换热系数先快速升高但在接近临界热流密度时有所下降;当调节入口压力时,随着喷嘴入口压力从0.6MPa升高至1.0MPa,临界热流密度呈现出先升高后降低的趋势;当入口压力为0.8MPa时,系统所能达到的临界热流密度最高,为276.1W.cm-2,相应的喷雾冷却壁面温度为26.8℃,说明当使用R22为喷雾介质时,文中实验系统具有高热流密度及低冷却表面温度的显著特点。

A closed pressure spray cooling system with R22 as a refrigerant was designed and set up to investigate the performance of phase change spray cooling.The experiments were conducted at a nozzle-to-surface distance of 22 cm,the inlet temperature of-3 ℃ and the spray backpressure of 0.34 MPa.The results show that the heat flux increased steadily with an increase in the power input when the inlet pressure value was maintained.Moreover,the heat transfer coefficient rose rapidly first and then dropped while the heat flux was approaching the critical heat flux（CHF）.When the inlet pressure rose from 0.6 MPa to 1.0 MPa,the CHF increased first and then decreased.The present system achieved a maximum CHF value of 276.1 W·cm-2 with the cooling surface temperature of 26.78 ℃ when the nozzle inlet pressure was 0.8 MPa.It appears that the present system with R22 as a spray medium can remove high heat power and keep low cooled surface temperature.