制冷学报2024，Vol.45Issue(3)：72-80,9.DOI:10.3969/j.issn.0253-4339.2024.03.072
跨临界CO2两相引射器喷嘴扩张段传热的影响分析
Analysis of the Influence of Heat Transfer in the Nozzle Divergence Section of Transcritical CO2 Two-phase Ejector
摘要
Abstract
The motive flow state in a transcritical CO2 ejector significantly affects its performance.The heat transfer on the wall of the motive nozzle can change the motive flow state,and its effect on the performance of the ejector should be studied.A CFD model of the transcritical CO2 two-phase ejector is constructed based on the homogeneous equilibrium model.The influence of heat transfer in the nozzle divergence section on the performance and flow field structure of the transcritical CO2 two-phase ejector is simulated.The effect of heat transfer on the system performance of using a split ejector at the condenser outlet is analyzed.The results show that the entrainment ratio of the ejector increases with an increase in the heat flux at the nozzle divergence section and the length of the nozzle divergence section.The effect is not obvious and can be ignored under a moderate heat flux,i.e.less than 120 kW/m2 since the entrainment ratio changes within 1%.In addition,the heat transfer in the nozzle divergence section has a slight effect on the internal flow field of the ejector.The temperature of the internal flow in the nozzle divergence section increases slightly,the vapor quality at the ejector outlet rises slightly,and the Mach numbers of the mixed flow at the nozzle outlet and in the mixing chamber increase.In the condenser outlet split ejector expansion refrigeration system,the fluid is subcooled using the ejector,and the coefficient of performance(COP)of the system is significantly improved,with a maximum COP increase ratio of 8.89%.In general,heating the divergence section of the motive nozzle of the ejector exerts minimal effect on its performance.However,it significantly improves the performance of the condenser outlet split-ejector expansion refrigeration system.关键词
两相引射器/均质平衡模型/传热/制冷系统/CO2Key words
two-phase ejector/homogeneous equilibrium model/heat transfer/refrigeration system/carbon dioxide分类
通用工业技术引用本文复制引用
冯义博,何阳,邓建强..跨临界CO2两相引射器喷嘴扩张段传热的影响分析[J].制冷学报,2024,45(3):72-80,9.基金项目
国家自然科学基金(52006160)资助项目.(The project was supported by the National Natural Science Foundation of China(No.52006160).) （52006160）
