Influence of surface roughness on a spray cooling system with R134a. Part II: Film thickness measurements
Influence of surface roughness on a spray cooling system with R134a. Part II: Film thickness measurements
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DOI：
10.1016/j.expthermflusci.2013.02.010
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发表时间：
2013-07
影响因子：
3.2
通讯作者：
E. Martínez-Galván;J. C. Ramos;R. Antón;Rahmatollah Khodabandeh
中科院分区：
文献类型：
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作者：
E. Martínez-Galván;J. C. Ramos;R. Antón;Rahmatollah Khodabandeh
在喷雾冷却试验台上对两种不同的加热器表面粗糙度和两种不同类型的喷嘴进行了R134a介质制冷剂的实验测量。本文给出了喷雾制冷工质膜厚的测量结果。分析和讨论了体积流量、表面粗糙度和喷嘴类型(通过喷雾参数)对总平均油膜厚度的影响。在附文中，给出了热传递测量的结果。结果表明，平均努塞尔数和液膜厚度沿喷雾冷却沸腾曲线的变化之间存在一定的关系。沿该曲线的换热状态不仅与平均努塞尔数的变化有关，而且与油膜厚度的变化有关。对这些变化的定性分析有助于更好地理解喷雾冷却过程中的换热机理。
Experimental measurements in a spray cooling test rig were carried out for two different heater surface roughnesses and for two different types of nozzles with the dielectric refrigerant R134a. In this paper, results of the sprayed refrigerant film thickness measurements are presented. The influence of the volumetric flow rate, the surface roughness and the type of nozzle (through the spray parameters) on the total average film thickness is analyzed and discussed. In a companion paper, results of the heat transfer measurements are presented. It has been found that there is a relation between the variations of the average Nusselt number and of the film thickness along the spray cooling boiling curve. The heat transfer regimes along that curve are related not only to a variation in the average Nusselt number but also to changes in the film thickness. The qualitative analysis of those variations served to better understand the heat transfer mechanisms occurring during the spray cooling.