Flow Boiling Heat Transfer Characteristics and Delayed Dry-Out Ability of Non-Azeotropic Mixtures R245fa/R134a in Microchannels  

作　　者：LU Yongjie LING Yongjun ZHUANG Yuan LI Chenyang OUYANG Hongsheng HAN Xiaohong 

机构地区：[1]Key Laboratory of Refrigeration and Cryogenic Technology of Zhejiang Province,Institute of Refrigeration and Cryogenics,Zhejiang University,Hangzhou,310007,China [2]Zhejiang Zhongguang Electrical Co.,Ltd.,Lishui,323000,China [3]State Key Lab for Fluorine Greenhouse Gases Replacement and Control Treatment,Zhejiang Research Institute of Chemical Industry,Hangzhou,310014,China

出　　处：《Journal of Thermal Science》2024年第3期1174-1188,共15页热科学学报（英文版）

基　　金：supported by the National Natural Science Foundation of China(No.52076185);the Natural Science Foundation of Zhejiang Province(No.LZ19E060001);the Open Project of Shanghai Key Laboratory of Multiphase Flow and Heat Transfer in Power Engineering(No.KF2019-02)。

摘　　要：Microchannel flow boiling heat transfer has the advantages of strong heat dissipation capacity,good temperature uniformity,and compact structure.It is an excellent way to thermally manage electronic devices,but when the heat flux exceeds CHF(Critical Heat Flux),the heat transfer performance deteriorates as the working fluid dries out.Non-azeotropic mixtures have the potential to effectively delay or avoid dry-out during the boiling process due to their temperature slide characteristics which causes the mass transfer resistance.To understand the influence of non-azeotropic mixtures on microchannel flow boiling,using the phase-change microchannel heat sink as the research object,the experiments on the flow boiling heat transfer performance of R245fa/R134a mixtures under different working conditions were carried out,and the characteristics of flow boiling heat transfer were obtained under the different working conditions,and comparison was developed with those of pure substance R245fa.The results demonstrated that a small amount of low-boiling-point components in the high-boiling-point working fluid inhibited boiling heat transfer to some extent,and lowered the average heat transfer coefficient under the non-dryout condition slightly lower than that of the pure substance;however,it also effectively delayed the onset of local dry-out and prevented significant deterioration in thermal transfer performance under the lower mass flow rate and higher heat flux,which could enhance the heat sink's stability.

关 键 词：MICROCHANNEL flow boiling non-azeotropic mixture heat transfer characteristics DRY-OUT 

分 类 号：TK124[动力工程及工程热物理—工程热物理]