扁管微小通道内R134a的沸腾换热试验  

Experiment on flow boiling heat transfer of R134a in mini-channel of flat tube

作　　者：詹宏波[1] 文涛[1] 张大林[1] 

机构地区：[1]南京航空航天大学航空宇航学院,南京210016

出　　处：《航空动力学报》2017年第7期1585-1591,共7页Journal of Aerospace Power

摘　　要：搭建适用于多种结构微小通道的沸腾换热试验系统,研究了制冷剂R134a在当量直径分别为0.63mm和0.72mm的多孔扁管微小通道内的沸腾换热特性。试验参数包括制冷剂质量流率为82~621kg/(m^2·s),饱和压力为0.22~0.63MPa,干度为0~1;采用等热流密度方式加热,热流密度范围为9.7~64kW/m^2。结果表明:R134a在扁管内沸腾换热中,当干度在0~0.6区间时,微小通道的传热系数明显高于常规通道,换热类型主要为核态沸腾,传热系数随热流密度和饱和压力的增大而增大,与质量流率关系不大;当干度大于0.6之后,传热系数随着干度的增大急剧减小,且在此干度区间,传热系数受热流密度和饱和压力影响较小,而受质量流率的影响相对较大。利用该结论和公开文献中R134a沸腾换热试验数据对Gungor-Winterton公式进行改进,改进后的公式对所有试验点的平均相对误差为-1.17%,平均绝对误差为19.24%,预测精度有了明显提高。An experimental study about R134a refrigerant flow boiling in a horizontal multiport flat tube mini-channel with the hydraulic diameter of 0.63 mm and 0.72 mm was carried out. The refrigerant was heated in uniform heat flux. The experiments were performed at the mass flux in range of 82- 621kg/（m2 · s）, heat flux in range of 9.7-64 kW/m2 , saturation pressure in range of 0. 22-0. 63MPa and vapor quality in range of 0-1. Results showed that when the vapor quality in range of 0- 0.6, the local heat transfer coefficients of mini-channel were higher than those of conventional channel, nucleate boiling was the main contributing factor, the local heat transfer coefficients increased with increasing heat flux and saturation pressure, but had little dependence with mass flux. When the vapor quality was bigger than 0. 6, the local transfer coefficients decreased sharply l the influences of heat flux and saturation pressure on local heat transfer coefficient were small, but closely related to mass flux. Gungor-Winterton correlation was modified based on the experimental R134a flow boiling heat transfer coefficient from present study and published literatures, with -1.71% of the mean relation deviation and 19.24% of the mean absolute relation deviation respectively, showing an obvious improvement.

关 键 词：微小通道 多孔扁管 R134A制冷剂 沸腾换热 传热系数 

分 类 号：V211.17[航空宇航科学与技术—航空宇航推进理论与工程] TK124[动力工程及工程热物理—工程热物理]