R417A在水平双侧强化管外沸腾换热研究

对3根双侧强化管在饱和温度为8℃工况下进行了水平管外R417A沸腾换热特性研究.采用Wilson热阻分离法得到管外沸腾表面传热系数,并对实验结果进行了热阻分析.实验结果表明：管内轧制出0.32～0.34 mm的螺旋槽道,可以使管内对流传热系数提高到光管Gnielinski公式计算值的2.524～ 2.658倍.相同管型的强化换热表面,其沸腾传热系数随壁面温差变化的趋势相似,肋密度42fpi的E30管沸腾传热系数比50fpi的E32管大4.5％,表明沸腾传热系数的大小及变化趋势与肋密度（孔隙直径）及管型密切相关.双侧强化管外R417A沸腾换热,管外热阻约占总热阻的70％,管外仍需进一步强化,才能...

Full description

Saved in:
Bibliographic Details
Published in制冷学报 Vol. 35; no. 3; pp. 114 - 118
Main Author 张定才 田松娜 冀文涛 赵安利 范晓伟 陶文铨
Format Journal Article
LanguageChinese
Published 中原工学院能源与环境学院 郑州450007%西安交通大学能源与动力工程学院热流科学与工程教育部重点实验室 西安710049 2014
Subjects
R417A
双侧强化管
沸腾换热
R417A
双侧强化管
boiling heat transfer
doubly-enhanced tubes
refrigerant 417A
沸腾换热
Online AccessGet full text
ISSN0253-4339
DOI10.3969/j.issn.0253-4339.2014.03.114

Cover

More Information
Summary:对3根双侧强化管在饱和温度为8℃工况下进行了水平管外R417A沸腾换热特性研究.采用Wilson热阻分离法得到管外沸腾表面传热系数,并对实验结果进行了热阻分析.实验结果表明：管内轧制出0.32～0.34 mm的螺旋槽道,可以使管内对流传热系数提高到光管Gnielinski公式计算值的2.524～ 2.658倍.相同管型的强化换热表面,其沸腾传热系数随壁面温差变化的趋势相似,肋密度42fpi的E30管沸腾传热系数比50fpi的E32管大4.5％,表明沸腾传热系数的大小及变化趋势与肋密度（孔隙直径）及管型密切相关.双侧强化管外R417A沸腾换热,管外热阻约占总热阻的70％,管外仍需进一步强化,才能明显提高总体传热性能.R417A在强化管外沸腾传热系数仅为近似条件下其主要组分R134a的三分之一,表明混合工质沸腾换热与纯工质有较大差异.
Bibliography:11-2182/TB
Experimental studies of boiling heat transfer of R417A on three single horizontal doubly-enhanced tubes have been conducted at the saturation temperature of 8 ℃. A modified Wilson plot technique was used to obtain the boiling heat transfer coefficients, and the thermal resistance analysis was conducted. The results indicate tbat the intube heat transfer coefficients of the three enhanced tubes are within 2. 524 - 2. 658 times as those of smooth tube, which were rolled 0.32 - 0.34 mm high spiral channel. For the same type of en- hanced heat transfer surface, the trends of boiling heat transfer coefficient with the wall temperature difference are similar. Boiling heat transfer coefficients of tube E30 （42 fin per inch） are 4.5 percent higher than those of tube E32（50 fpi） at the same temperature differ- ence. It is indicated that the boiling heat transfer coefficient and its trend were closely related with fin density （pore diameter） and tube type. Boiling heat transfer of R417A on doubly- enhanced tu
ISSN:0253-4339
DOI:10.3969/j.issn.0253-4339.2014.03.114