摘要
以R134a为工质在作者研制的三维微肋管内进行了水平流动沸腾换热实验研究,通过可视化措施对流型及其转换进行了观测,结果表明,在Tailer-Dukler流型图上,三维微肋管内沸腾流型的分界线与光滑管有所不同,其中间歇流与环状流的判据由Xtt等于1.6减小到Xtt等于0.42,而波状流向环状流转变的Fr数有所增加;而在中等质量流速下环状流与局部蒸干区的转变主要受热流密度的影响。同时,对三维微肋管内沸腾换热特点进行了讨论,并对得到的实验数据建立了分区换热关联式,这些不同流型下的换热关联式的计算值能较好地同实验数据相吻合。
The heat transfer characteristics are strongly dependent on the flow pattern in the tube-boiling. Therefore, it is very important to know which flow pattern is expected to exist at certain flow conditions in a tube-boiling and to develop heat transfer correlations consistent with the prevailing heat transfer mechanism in each flow pattern. The boiling heat transfer for R134a is investigated experimentally in a three-dimensional (3-D) microfin tube. In the range of experimental conditions, six distinguishable flow patterns ( bubble flow, plug flow, stratified flow, wavy flow, slug flow and annular flow) are recorded by a video camera. The obtained results are constructed in the Taitel-Dukle flow pattern map. The findings show the annular flow region of 3-D microfin tube is different from that of smooth tube. The regime transition criterion Xtt decreases from 1.6 to 0.42 between intermittent flow and annular flow, and the regime transition criterion Fr have lightly increase between wave flow and annular flow. Based on the experimental data, the empirical correlations are obtained in different flow pattern and the calculated data of these correlations agree well with the experimental data.
出处
《重庆大学学报（自然科学版）》
EI
CAS
CSCD
北大核心
2003年第8期109-113,共5页
Journal of Chongqing University
基金
国家重点基础研究专项经费资助(G2000026305)
关键词
R134A
微肋管
沸腾
流型
换热关联式
R134a
microfin tube
boiling
flow pattern
heat transfer correlations
