摘要
为提高换热强度、解决设备内部高热流密度散热问题,采用实验方法研究R141b在不同直径(D=0.5mm和1.0mm)水平圆形微通道内的沸腾换热特性,分析了热流密度(q=2.0kW/m^2~47.6kW/m^2)、质量干度(x=0~0.6)、质量流速(G=111.11kg/(m^2·s)~333.33kg/(m^2·s))的变化对平均传热系数h的影响,探究不同情况下影响沸腾换热的主导因素。实验研究表明:平均传热系数h随热流密度q的增加而减小,在不同范围内减小速率有明显差异;热流密度q=2kW/m^2~5kW/m^2时质量流速G对平均传热系数h影响较明显,热流密度较高时质量流速G对换热影响很小;在质量流速G=111.11kg/(m^2·s)~333.33kg/(m^2·s),质量干度x>0.3时,平均传热系数h随质量干度x增加而明显下降,在设计微通道换热器时应尽量使R141b处于初始沸腾阶段以获得更好换热效果,并采取一定措施预防干度过高引起的换热恶化。
In order to intensify heat transfer and solve the problem of high heat flux and heat dissipation in-side the equipment,the boiling heat transfer characteristics of R141 b in horizontal micro-channels with differentdiameters(D=0.5 mm and 1.0 mm)were studied experimentally.The effects of heat flux(q=2.0 kW/m^2~47.6 kW/m^2),vapor quality(x=0~0.6)and mass flow rate(G=111.11 kg/(m^2·s)~333.33 kg/(m^2·s))on the average heattransfer coefficient h were analyzed,and the dominant factors affecting boiling heat transfer were explored underdifferent conditions.The experimental study showed that the average heat transfer coefficient h decreased with theincrease of heat flux q in significantly different rate according to different range.The effects of mass flow rate G onthe average heat transfer coefficient h are obvious when heat flux q=2 kW/m^2~5 kW/m^2,while when the heat flux ishigh,the mass flow rate G has little effect on the heat transfer.At different mass flow rate(G=111.11 kg/(m^2·s)~333.33 kg/(m^2·s))when the vapor quality x>0.3,the average heat transfer coefficient h decreased with increas-ing vapor quality x.Micro-channel heat exchangers should be well-designed to insure R141 b working under theinitial boiling stage to achieve better heat exchange effect,and certain measures should be taken to prevent the heat deterioration caused by excessive dryness.
作者
张宗卫
徐文迪
刘聪
付东金
周志豪
ZHANG Zong-wei;XU Wen-di;LIU Cong;FU Dong-jin;ZHOU Zhi-hao(College of Aeronautical Engineering,Civil Aviation University of China,Tianjin 300300,China;College of Air Traffic Management,Civil Aviation University of China,Tianjin 300300,China)
出处
《推进技术》
EI
CAS
CSCD
北大核心
2019年第6期1363-1369,共7页
Journal of Propulsion Technology
基金
中央高校基本科研业务费中国民航大学专项(3122014C006)
中国民航大学科研启动基金项目(2013QD11S)
关键词
R141B
换热特性
圆形微通道
沸腾
平均传热系数
R141b
Heat transfer characteristic
Circular micro-channel
Boiling
Average heat transfer coefficient
