R141b在烧结高通量管外流动沸腾换热实验研究
Flow Boiling of R141b on Externally Sintered High-Flux Tubes
王科 1赵学智 1叶晶 2揭涛2
作者信息
- 1. 中国石油大学(北京)机械与储运工程学院,北京 102249
- 2. 中国船舶集团有限公司第七一一研究所,上海 201100
- 折叠
摘要
烧结型高通量管是一种新型的强化换热元件,能在较低的壁面过热度条件下产生剧烈的核态沸腾,促进工质的相变换热.为探究烧结多孔层对流动沸腾换热特性的影响规律,本文以制冷剂R141b为实验工质,对外径为25 mm、涂层厚度为0.3 mm、孔隙度分别为65％和75％的外烧结型高通量管开展了实验研究.结果表明,在相同的壁面过热度条件下,高通量管较光管能大幅提高壁面热流密度,且孔隙率更高的高通量管其壁面热流密度更高.增加高通量管的孔隙度能增加汽化核心的数量和汽泡脱离的频率,但当加热壁面温度升高到一定程度时,汽泡无法及时从多孔层中逃逸而形成局部汽膜,导致高通量管的换热系数降低.
Abstract
The sintered high-flux tube is an innovative heat transfer element that exhibits enhanced heat transfer capabilities.It is capable of inducing vigorous nuclear boiling even at low wall super-heat conditions,thereby facilitating the efficient heat transfer of the working medium.In order to investigate the impact of a sintered porous layer on the characteristics of flow boiling heat transfer,this study conducted experimental research on externally sintered high-flux tubes.The tubes had an outer diameter of 25 mm,a coating thickness of 0.3 mm,and porosities of 65％and 75％respec-tively.The experimental working medium used in this study was refrigerant R141b.The results indicate that,when subjected to identical wall superheat conditions,the high-flux tube exhibits a substantial increase in wall heat flux compared to the smooth tube.Furthermore,it is observed that the high-flux tube with greater porosity demonstrates an even higher wall heat flux.Increasing the porosity of the high-flux tube has been found to have a positive effect on the number of vaporized cores and the frequency of bubble detachment.However,it should be noted that when the heating wall temperature reaches a certain threshold,the bubbles are unable to escape from the porous layer and instead form a localized vapor film.This phenomenon ultimately leads to a decrease in the heat transfer coefficient of the high-flux tube.
关键词
高通量管/强化换热/流动沸腾/过冷沸腾/R141bKey words
high-flux tube/heat exchange enhancement/flow boiling/subcooled boiling/R141b引用本文复制引用
出版年
2024
NETL
NSTL
万方数据