| 摘要: |
| 研究R22和R1234ze(E)在胀管前、后外径分别为5.10和5.26 mm微肋管内的截面尺寸变化、凝结换热和摩擦压降特性。分析质量流速、干度及胀管对凝结换热系数和摩擦压力梯度的影响。采用关联式对试验结果进行预测,并对关联式的预测性能进行分析。结果表明:胀管后微肋管的结构会发生一定程度的变形;凝结换热系数和摩擦压力梯度均随质量流速和干度增大而增大;质量流速为100 kg/(m2·s)时,胀管会削弱微肋管的凝结换热性能;质量流速为200和300 kg/(m2·s)时,胀管对换热系数的影响不明显;而质量流速为100～300 kg/(m2·s)时,胀管对摩擦压力梯度的影响不显著。 |
| 关键词: 微肋管 胀管 两相流动 凝结换热 摩擦压降 |
| DOI：10.3969/j.issn.1673-5005.2020.02.017 |
| 分类号::TK 124 |
| 文献标识码:A |
| 基金项目:国家自然科学基金项目(51904325)；山东省自然科学基金项目(ZR2017LEE003) |
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| Impact of tube expansion on fluid flow and condensation heat transfer for R22 and R1234ze(E) in micro-fin tubes |
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LIU Na1, LI Dekai2, LI Yuxing2, LI Junming3
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(1.School of Environmental and Municipal Engineering, Qingdao University of Technology, Qingdao 266033, China;2.College of Pipeline and Civil Engineering in China University of Petroleum (East China), Qingdao 266580, China;3.Key Laboratory for Thermal Science and Power Engineering of Ministry of Education, Department of Thermal Engineering, Tsinghua University, Beijing 100084, China)
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| Abstract: |
| The measured cross section variation, condensation heat transfer and friction pressure drop were studied during the condensation of R22 and R1234ze(E) in pristine (5.10 mm outer diameter(OD)) and expanded (5.26 mm OD) micro-fin tubes. The effects of mass flux, vapor quality and tube expansion on the condensation heat transfer coefficients and friction pressure gradients for R22 and R1234ze(E) were analyzed. Correlations were used to predict the experimental results and predicted performances were assessed. The results show that the micro-fin tube deformed after expansion. The condensation heat transfer coefficients and friction pressure gradients both increase with the mass flux and vapor quality. The tube expansion degraded the condensation heat transfer performance in the micro-fin tube with the mass flux being 100 kg/(m2·s). The effect of tube expansion on the heat transfer coefficient was not apparent with the mass fluxes being 200 kg/(m2·s) and 300 kg/(m2·s). However, for the mass fluxes being 100～300 kg/(m2·s), the effect of tube expansion on the friction pressure gradient was not significant. |
| Key words: micro-fin tube tube expansion two-phase flow condensation heat transfer friction pressure drop |
