摘要
对内径为1、2、3 mm的水平不锈钢圆管内R290两相流动沸腾换热特性进行了理论与实验研究。分析了热流密度为15~35 kW/m^2、质量流率为76~200 kg/(m^2·s)、饱和温度为16~36℃、干度为0~1时的管内传热特性。研究结果表明:热流密度的增加促进管内核态沸腾,换热得到强化,从而导致换热系数随之增加;质量流率的增加促进管内由核态沸腾换热向对流换热转化,换热系数也随之增加;饱和温度的增加促进管内气泡核心的形成速率加快,强化管内沸腾换热;管径的减小导致微尺度效应增加,从而导致换热系数随之增加;在整个换热过程中干涸前平均换热系数、干涸过程中的平均换热系数分别占总换热系数的40%、37%。
Theoretical and experimental study of R290 two-phase flow boiling heat transfer characteristics in the stain- less steel round tubes, inside diameter of which was 1 ram, 2 mm and 3 mm was conducted. The heat flux density was 15 -35 kW/m^2, the mass flow rate was 76 -200 kg/（m^2·s）, the saturation temperature was 16 - 36℃, and the range of dryness was 0 - 1. The results showed that the increase of heat flux density promoted the core tube boiling heat transfer; the increase of mass flew rate promoted the tube from the nucleate boiling heat transfer to the convective heat transfer ; the increase of saturation temperature promoted the formation of the core tube bubbles ; the decreases of the in- side diameter made the microscale effect increased, which would all made the heat transfer coefficient increased. Be- fore the dryout, the average heat transfer accounted for 40% of the total heat transfer. In the process of the dryout, the average heat transfer accounted for 37% of the total heat transfer.
出处
《能源工程》
2016年第6期1-5,共5页
Energy Engineering
基金
上海市教育委员会重点学科资助项目(J50502)
上海市科委建设项目(13DZ2260900)
关键词
微细管
R290
两相流动
沸腾换热
干涸
micro tube
R290
two-phase flow
boiling heat transfer
dryout
