Liquid film flow and heat transfer model under spray impact

doi:10.11949/j.issn.0438-1157.20171067

Abstract

Abstract:

Aiming at the shortcomings of the existing calculation model in spray cooling, based on mass, momentum and energy conservation equations, the liquid film flow and heat transfer equations of spray cooling in non-boiling region are established,and magnitude analysis method is applied to simplify equations, and numerical method is used to solve the model. Based on the given values of droplet velocity and temperature, the film thickness, average heat flux and liquid outflow temperature are solved by the model, then the calculated results are compared with the experimental results. The comparison results show that the liquid film thickness difference is less than 6%. The difference of average heat flux and final liquid temperature is less than 10%, and the results that difference less than 5% account for more than 60%. The excellent agreement between simulation and experiment confirms that this model can reasonably reflect flow and heat transfer in spray cooling. The calculated results of film thickness and temperature can deepen the understanding of spray cooling heat transfer mechanism.

Key words: spray cooling, flow, heat transfer, computational fluid dynamics,CFD, model reduction

摘要：

针对现有喷雾冷却计算模型的不足，以质量、动量、能量守恒方程为基础，建立喷雾冷却非沸腾区的液膜流动与传热方程，并采用数量级分析的方法对方程简化，最后运用数值方法对模型进行求解。给定液滴速度及液体温度，由模型计算液膜厚度、平均热通量与液体流出温度，与实验测试结果对照。结果显示，液膜厚度的计算结果与实验结果相差6%以内；平均热通量和液体离开待冷却表面的最终温度计算结果与实验结果相差10%以内，且超过60%的计算结果偏差小于5%。计算结果与实验结果的高度匹配证明该模型可较好地反映喷雾冷却过程的流动与换热。由模型可以获取不同位置处液膜厚度与温度，从而加深对喷雾冷却传热机理的理解。

关键词: 喷雾冷却, 流动, 传热, 计算流体力学, CFD, 模型简化

CLC Number:

TK124

QI Hang, ZHANG Wei, GONG Liang. Liquid film flow and heat transfer model under spray impact[J]. CIESC Journal, 2018, 69(5): 2014-2022.

亓航, 张伟, 巩亮. 喷雾冲击条件下液膜流动与传热模型[J]. 化工学报, 2018, 69(5): 2014-2022.

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