| 摘要: |
| 本文对低压制冷剂R1233zd(E)在平行小通道内的流动沸腾换热过程进行了可视化实验研究，分析了制冷剂在平行通道内流型的演变与分布，在此基础上讨论了流型对换热特性的影响规律。结果表明：随热流密度的增加，在通道内观察到泡状流、段塞流、搅拌流和波形环状流；在较高的热流密度下，部分通道出现回流现象。此外，不同通道内流型的分布规律略有不同；通道中局部表面传热系数变化趋势随流型的演变可以分为不同阶段，中部与出口处的局部表面传热系数呈现不同的变化趋势；当干度小于0.1时，表面传热系数几乎不受质量通量的影响；随着干度增加，表面传热系数与质量通量呈正相关关系。 |
| 关键词: 平行通道 流动沸腾 可视化 流型分布 换热特性 |
| DOI： |
| Received:March 02, 2022Revised:April 10, 2022 |
| 基金项目: |
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| Visualization of R1233zd(E) Flow Boiling in Parallel Mini-channels |
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Zhang Zhao1, Fang Yidong1,2, Xu Dan1, Hu Lingren1, Wang Yuchen1, Huang Yuqi3
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| (1.School of Energy and Power Engineering, University of Shanghai for Science and Technology;2.Shanghai Key Laboratory of Multiphase Flow and Heat Transfer in Power Engineering;3.College of Energy Engineering, Zhejiang University) |
| Abstract: |
| This study conducts a visual experimental investigation on low-pressure refrigerant R1233zd(E) in a parallel mini-channel heat sink. The evolution and distribution of flow patterns in parallel channels and the influence of flow patterns on heat-transfer characteristics were analyzed. Four flow patterns (bubbly flow, slug flow, churn flow, and wavy-annular flow) were observed in the channels when increasing the heat flux. At high heat flux levels, reverse flow occurs in some channels. In addition, it is observed that the distribution of flow patterns in different channels is slightly different. The variation trend of the local surface coefficient of the heat transfer can be divided into different stages based on the evolution of the flow pattern. Moreover, the middle and outlet local surface coefficients of the heat transfer exhibit different variation trends. When the vapor quality is less than 0.1, the surface coefficient of the heat transfer is almost independent of the mass flux. With an increase in vapor quality, the surface coefficient of the heat transfer is positively correlated with the mass flux. |
| Key words: parallel channel flow boiling visualization flow pattern distribution heat transfer characteristics |
