R134a喷射冲击相变制冷的数值模拟及结构优化

Numerical thermal analysis and optimization of R134 jet impingement cooling

为分析R134a喷射冲击相变制冷的传热效果,以数值模拟为基础,采用计算流体力学的思路,通过控制变量的方法,研究各个物理因素对冷却效果的影响。流道长度L为定值,分析变量为流道高度C,喷嘴宽度W,喉部宽度D1,喷射出口宽度D2,喷嘴高度H,液相与气相的体积分数比ω。结果表明:热表面的冷却效果随流道高度和喷嘴宽度的增大而减小,随液相与气相的体积分数比ω的增大而增大;而在止滞点附近的冷却效果随喉部宽度和喷嘴高度的减小而增大,在流道出口附近随喉部宽度和喷嘴高度的增大而增大。在止滞点处,冷却效果最佳的结构模型为:C/L为0.02,W/L为0.05,D1/L为0.01,D2/L为0.015,H/L为0.03。

this paper investigated the influence of the phase - change cooling with a confined slot R134a jet based on numer- ical analysis and numerical simulation in computational fluid dynamics（CFD）. The size of the channel length is fixed. Some var- iable parameters are the channel height （ C）, the nozzle width （ W）, the throat width （D1）, the jet outlet width （D2 ）, the nozzle height （H） and the volume fraction of liquid phase and gas phase ratio （to）. The results reveal that the Nusselt number decrea- ses as the increasing of the channel height and the nozzle width , and that increases as the increasing of the volume fraction of liq- uid phase and gas phase ratio. The Nusselt number near the stagnation point increases as decreasing of the throat width and the nozzle height, and that near exits of channels increased as increasing the throat width and the nozzle height. The optimization model at the stagnation point are C/L =0. 02, W/L =0. 05 ,D1/L =0. 01 ,D2/L =0. 015 ,H/L =0. 03.