江苏大学学报（自然科学版）2026，Vol.47Issue(2)：175-181,7.DOI:10.3969/j.issn.1671-7775.2026.02.007
水平横槽管外R245fa降膜蒸发的流动与换热特性
Flow and heat transfer characteristics of R245fa falling film evaporation outside horizontal grooved tube
摘要
Abstract
Based on the gas-liquid two-phase flow and evaporation model,to investigate the process of the falling film evaporation outside horizontal tube,the liquid film flows of liquid film spreading,liquid film thickness and distribution and the heat transfer characteristics of refrigerant R245fa were compared outside smooth tube and grooved tube under the conditions of low,medium and high heat flux with q values of 500,5 000 and 20 000 W/m2 at falling film Reynolds number Re of 1 690.The results show that the liquid film spreads faster outside the grooved tube than that outside the smooth tube.It takes 0.192 s for the liquid film to completely cover the external wall of the grooved tube and 0.222 s for the smooth tube,respectively.Compared with the smooth tube,the thickness of the liquid film outside horizontal grooved tube is thinner,and the thickness decrease is mainly related to the circumferential angle.At the cross section of the two liquid films meeting,the thickness decrease values are about respective 20％,10％and 13％when the circumferential angles are[0°,60°),[60°,160°)and[160°,180°].The local heat transfer coefficients outside the horizontal grooved tube are related to the magnitude of liquid film thinning and are respective 1.5-3.0,1.1-1.2 and 1.1-1.5 times those outside the smooth tube when the circumferential angles are respective[0°,60°),[60°,160°)and[160°,180°].The average heat transfer coefficient of horizontal grooved tube is higher than that of smooth tube.Under the conditions of medium and high heat flux,the sudden local deformations of the liquid film outside the smooth tube can be found.Especially at the cross section of the liquid spraying from the nozzle at the circumferential angle of 110°-180°,the bubble in the liquid film outside the smooth tube is large enough to cause the sharp decrease of liquid film thickness due to the necking effect,which leads to the local dryout outside the smooth tube.However,the local dryout can be effectively avoided for the horizontal grooved tube.关键词
水平横槽管/降膜蒸发/液膜流动/汽液两相流/传热Key words
horizontal grooved tube/falling film evaporation/liquid film flow/gas-liquid two-phase flow/heat transfer分类
能源科技引用本文复制引用
王迎慧,王耀,卜昶瑞,杭范辰..水平横槽管外R245fa降膜蒸发的流动与换热特性[J].江苏大学学报（自然科学版）,2026,47(2):175-181,7.基金项目
国家自然科学基金资助项目(52276067) （52276067）
