超声波作用下微细通道内纳米制冷剂沸腾流动特性研究  

Study on boiling flow characteristics of nanorefrigerant in microchannels under ultrasonic waves

作　　者：罗小平[1] 李桂中 刘倩 廖政标 LUO XiaoPing;LI GuiZhong;LIU Qian;LIAO ZhengBiao(School of Mechanical and Automotive Engineering,South China University of Technology,Guangzhou 510640,China)

机构地区：[1]华南理工大学机械与汽车工程学院,广州510640

出　　处：《中国科学：技术科学》2022年第8期1212-1222,共11页Scientia Sinica(Technologica)

基　　金：国家自然科学基金(批准号:22178118);广东省自然科学基金(编号:2019A1515011053)资助项目。

摘　　要：为研究超声波和纳米颗粒对微细通道流动沸腾压降的影响,采用两步法配置质量分数为0.1%,0.2%,0.3%的TiO_(2)/R141b纳米制冷剂,设计实验系统的绝对压力为152 kPa,施加的超声波功率为50 W,频率为23 kHz,在2 mm×2 mm铝基矩形微细通道中进行流动沸腾实验,分析超声波作用下不同质量分数纳米制冷剂流动特性差异,并结合可视化结果分析纳米颗粒、超声作用对微细通道内工质流动状态的影响.研究结果表明:本实验范围内,在制冷剂R141b中添加TiO_(2)纳米颗粒和施加超声波可有效减小微细通道流动沸腾压降,低热流密度阶段超声波对低质量分数纳米制冷剂沸腾流动压降的影响更显著.该研究结果可以为超声波强化微通道换热器换热性能优化研究提供新思路.To study the influence of ultrasonic waves and nanoparticles on flow boiling pressure drop and pressure drop fluctuation in microchannels,a two-step method was used to prepare TiO_(2)/R141b nanorefrigerant with mass fractions of 0.1%,0.2%,and 0.3%.The absolute pressure in the experimental system was set to 152 kPa,with an ultrasonic power of 50 W and a frequency of 23 kHz.The flow boiling experiment was carried out in a 2 mm×2 mm aluminum rectangular microchannel to analyze the flow characteristics of nanorefrigerant with different mass fractions under the action of ultrasonic waves.The influence of nanoparticles and ultrasonic waves on the flow state of the working medium in the microchannel was analyzed combined with the visualization results.The results show that adding TiO_(2) nanoparticles to refrigerant R141b and using ultrasonic wave to reduce the flow boiling pressure drop in the microchannel can effectively reduce the flow boiling pressure drop in this experiment,with ultrasonic wave having a more significant effect on the flow boiling pressure drop at the stage of low heat flux density.These findings could lead to a novel approach to optimizing the ultrasonic enhanced heat transfer performance of microchannel heat exchangers.

关 键 词：微细通道 纳米制冷剂 超声波 流动沸腾 压降 

分 类 号：TK124[动力工程及工程热物理—工程热物理] TN03[动力工程及工程热物理—热能工程]