摘要
本文研究了三种强化管对降膜蒸发换热效果的影响,利用热阻分析的方法,求得不同工况下降膜蒸发的换热系数。以水为介质,实验在绝对压力为1000Pa的条件下进行。通过对换热系数与降膜流量之间关系的研究,发现随着流量的增大,降膜蒸发过程分成管壁部分干涸以及全湿润两个状态;当流量处于转变值时,降膜蒸发的换热系数达到最大值。另外结果表明,当降膜雷诺数在10～110范围内,Turbo-CAB(26fpi)管表面的降膜蒸发换热系数是光管的3～5倍;但当液膜完全覆盖Turbo-CAB的翅片时,其强化换热效果将变差。
This paper reports an experimental study on water falling film evaporation on three types of enhanced tubes.Using the heat resistance method,the heat transfer coefficients of falling film evaporation on different working conditions are calculated.Water films evaporate at the absolute pressure of 1000 Pa.The relationship between the falling film Reynolds number and the heat transfer coefficients is studied.Results show that as the Reynolds number increases,falling film evaporation goes through from partial dryout regime to fully wet regime.The mean heat transfer coefficients reach peak values in the transition point.In the Reynolds number range of 10～110,Turbo-CAB（26 fpi） has a 3-5 times higher falling film heat transfer coefficient than smooth tubes.But when the film is thick enough to cover the fins on the CAB tubes,its heat transfer enhancement capacity is deteriorated.
出处
《工程热物理学报》
EI
CAS
CSCD
北大核心
2010年第11期1893-1896,共4页
Journal of Engineering Thermophysics
基金
国家自然科学基金资助项目(No.50976096)
国家863高技术研究发展计划资助项目(No.2007AA05Z226)
关键词
强化管
降膜蒸发
强化换热
干斑
enhanced tubes
falling film evaporation
heat transfer enhancement
dry patch
