采用R134a工质的相变喷雾冷却性能实验研究
Experimental Study on Heat Transfer Performance of Phase Change Spray Cooling with R134a

为了研究大热流密度相变喷雾的冷却特性,搭建了以R134a为冷却工质的闭式循环喷雾实验台,开展了采用R134a工质的相变喷雾冷却性能实验。实验工况为:喷雾高度13 mm,喷雾腔压力0.2 MPa,喷嘴入口温度0℃,喷雾流量范围为0.210 7~0.355 8 L/min。实验结果表明:当喷雾流量保持不变时,增大加热功率,热流密度增大,表面换热系数先快速升高最后有所下降;随着喷雾流量从0.210 7 L/min增加到0.355 8 L/min,临界热流密度呈现上升趋势;当流量为0.355 8 L/min时,获得最高的临界热流密度(CHF)为94？？75 W/cm2,此时冷却表面的壁面温度为35.42℃。这说明使用环保工质R134a作为冷却剂的喷雾冷却系统能同时满足高热流密度和低换热表面温度的要求,具有良好、稳定的换热冷却能力。
A closed loop spray cooling system with R134a refrigerant was designed, and experiments of cooling performance were conducted to make a deep study on high heat flux phase change spray cooling mechanism. The experiments were conducted at the spray height of 13 mm, the spray chamber pressure of 0.2 MPa and the inlet temperature of 0℃. The range of flow rate was from 0.210 7 L/min to 0.355 8 L/min. The results show that the heat flux increases steadily with an increase in the power input when the flow rate keeps unchanged. Moreover, the heat transfer coefficient rises rapidly first and then fall1. The heat flux has an increasing trend when the flow rate increases form 0.210 7 L/min to 0.355 8 L/min, and the maximum heat flux with value 94.75 W/cm2 is obtained when the flow rate is 0.355 8 L/min. Meanwhile, the spray cooling surface temperature keeps at 35.42℃. The results of experiments indicate that R134a has a stable heat cooling capacity as a spray cooling refrigerant and meets the requirement of high heat flux with low temperature of cooling surface