376-润滑油对自然循环传热性能的影响研究.pdfVIP

润滑油对两相自然循环传热性能的影响研 究 1 1 2 2 2 张朋磊 陆启航 李先庭 石文星 王宝龙 (1:南京航空航天大学, 南京, 210016; 2:清华大学, 北京, 100084) 摘 要：在两相 自然循环与蒸气压缩复合空调机组中，自然循环运行时制冷剂中不可 避免地含有润滑油，故掌握润滑油对于两相 自然循环性能的影响规律有助于复合机组的优 化设计和运行调控。本文搭建了带油的两相 自然循环性能测试实验台，通过折射率动态测 量循环含油率，研究了不同工况下润滑油对两相 自然循环性能的影响规律。结果表明：在 两相 自然循环中，大部分润滑油停留在蒸发器内，主要影响蒸发侧传热性能；当两相 自然 循环工况较好、蒸发器无过热时，加入润滑油后油膜将减弱自然循环的传热性能；当两相 自然循环工况较差（比如流动阻力大、高差小、充注量小），蒸发器过热严重时，因润滑油 的 “发泡”作用增大了浸润面积，缓解了蒸发器过热蒸干现象，有助于强化自然循环传热 性能。 关键词：两相自然循环；润滑油；复合机组；全年供冷 EFFECT OF LUBRICATING OIL ON THE PERFORMANCE OF TWO-PHASE NATURAL CIRCULATION 1 2 2 2 Zhang Penglei , Li Xianting , Shi Wenxing , Wang Baolong (1, Nanjing University of Aeronautics and Astronautics, Nanjing, 2 10016; 2, Tsinghua University, Beijing, 100084) Abstract:The integrated unit combining two-phase natural circulation and vapor compression inevitably contains lubricating oil, to master the effect of lubricating oil on the two-phase natural circulation performance helps optimization design and operation control of the unit. In the paper, a test bench on natural circulation with oil was developed, and the oil circulation ratio (OCR) was measured by refractive index. Results show that: in the natural circulation, the lubricating oil most stays within the evaporator, and the main affects heat transfer effciency of the evaporator; when working condition of the natural circulation is good, without overheating in the evaporator, the oil is harmful to heat transfer performance, mainly because the oil film increases the thermal resistance; and when the working condition of the natural circulation is poor, with significant overheating in the evaporator, the oil is beneficial to heat transfer performance, mainly beca