矩形微槽道内R134a流动沸腾换热特性的实验研究  

Experimental Study on Flow Boiling Heat Transfer Characteristics of R134a in a Rectangular Micro-channel

作　　者：党超[1,2] 贾力[1,2] 黄浅[1,2] 

机构地区：[1]北京交通大学机械与电子控制工程学院热能工程研究所,北京100044 [2]微细尺度流动与相变传热北京市重点实验室,北京100044

出　　处：《工程热物理学报》2017年第6期1327-1332,共6页Journal of Engineering Thermophysics

基　　金：国家自然科学基金资助项目(No.51376019)

摘　　要：本文主要研究了制冷剂R134a.在水平矩形(截面为1 mm×1 mm)微槽道内的流动沸腾换热特性。通过可视化手段观察到流动沸腾过程中的流型变化。同时得到了质量流速在60~1100 kg/(m^2s)、热流密度在33~120 kW/m^2时的流动沸腾换热系数,并对R134a的沸腾曲线作了讨论。通过可视化结果,发现了从泡状流到干涸流的7种流型。换热系数随着热流密度的增加而增加,干涸流的出现会导致换热系数迅速减小。核态沸腾传热在受限气泡到弹状流阶段得到增强。在搅混-环状流到环状流阶段,R134a的传热系数稳定在一个较高的值。此外,质量流速越大,CHF值越高。In the present paper, the flow boiling heat transfer characteristics of R134a are experimen- tally investigated in a single visualized rectangular micro-channel with the cross-sectional area of 1 mm× 1 mm. The flow pattern transitions and flow boiling heat transfer coefficients are obtained under the mass flux and heat flux ranging from 60-1100 kg/m2 s and 33-120 kW/m2, respectively. The boiling curves of R134a are also discussed. Based on the visualization results, seven flow types are iden- tified from bubbly flow to dry-out flow. The flow boiling heat transfer coefficient of R134a increased with the increasing heat flux. The occurrence of the dry-out flow resulted in a drastic decrease in the heat transfer coefficient. The nucleate boiling heat transfer was enhanced in the confined bubble to slug flow stage. During the churn-annular to annular flow stage, the heat transfer coefficient of R134a was maintained at a relatively stable high value. Besides, the larger the mass flux, the higher the CHF.

关 键 词：流动沸腾 可视化 传热系数 CHF 

分 类 号：TK123[动力工程及工程热物理—工程热物理]