雾化特性及系统参数对闭式喷雾冷却系统性能的影响

摘要

A closed-loop R22 spray cooling system was established.Three types of nozzles were applied and the influences of nozzle parameter and spray height were studied.The results show that the effects of medium flow rate and the atomization angle both should be considered.And the nozzle with small atomization angle is more suitable for the low spray height conditions.Meanwhile,the influences of system parameters including the super-cooling degree and the charging pressure were investigated.It is obtained that the spray cooling performance is enhanced by the increase of the super-cooling degree.The enhancement effect decreases to the increase of the super-cooling degree.The variations of the heat transfer coefficient and the surface temperature are proportional to the charging pressure.Therefore high charging pressure is not beneficial for the cooling of surfaces requiring low surface temperature.%搭建了以R22为冷却介质的闭式喷雾冷却实验台,通过更换3种不同的喷嘴,分析对比了不同喷嘴类型和喷雾高度下传热性能的变化规律.实验结果表明:选择喷嘴时必须同时考虑喷雾流量和雾化角度的影响;雾化角较小的喷嘴在低高度下适用性较好.同时,研究了系统参数如过冷度和充注压力对喷雾冷却传热性能的影响,得出过冷度对喷雾冷却性能有一定促进作用,但过冷度越大,促进效果越弱;表面传热系数和表面温度均随充注压力的升高而升高,因此高充注压力不适用于需严格控制温度的表面冷却.