Flow boiling heat transfer, pressure drop and dryout characteristics of R1234yf: Experimental results and predictions
Flow boiling heat transfer, pressure drop and dryout characteristics of R1234yf: Experimental results and predictions
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DOI：
10.1016/j.expthermflusci.2015.03.021
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发表时间：
2015-09
影响因子：
3.2
通讯作者：
Z. Anwar;Z. Anwar;B. Palm;Rahmatollah Khodabandeh
中科院分区：
文献类型：
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作者：
Z. Anwar;Z. Anwar;B. Palm;Rahmatollah Khodabandeh
本文报道了R1234yf在立式不锈钢试验段（内径1.60 mm，受热长度245 mm）中，在上向流动条件下的流动沸腾换热、压降和干燥特性。实验在27°C和32°C饱和温度下进行，质量通量为100-500 kg/m2s，外加热流密度为5-130 kW/m2。试验过程中，外加热流密度逐渐增大，直至干化完成。在相似的条件下，用R134a在相同的试验装置中重复试验，比较两种制冷剂的热性能。结果表明：沸腾换热受外加热流密度和操作压力的强烈控制，对质量流密度和蒸汽质量的依赖较小；摩擦压降随质量通量和蒸汽质量的增大而增大，随饱和温度的升高而减小。干干的迹象首先出现在蒸汽质量为85%时，随着质量通量的增加，干干的迹象普遍增加。系统压力变化的影响不显著。实验结果（沸腾传热、压降和干燥热流密度）与文献中众所周知的相关性（宏观和微观尺度通道）的预测结果进行了比较。
Flow boiling heat transfer, pressure drop and dryout characteristics of R1234yf in a vertical stainless steel test section (1.60 mm inside diameter and 245 mm heated length) under upward flow conditions are reported in this article. The experiments were carried out at 27 and 32 °C saturation temperatures with five mass fluxes in the range of 100–500 kg/m2s while the applied heat flux was in the range of 5–130 kW/m2. The experiments were carried out with gradual increase of the applied heat flux til completion of dryout. Under similar conditions, tests were repeated with R134a in the same test setup to compare thermal performance of these two refrigerants. The results showed that boiling heat transfer was strongly controlled by the applied heat flux and operating pressure with insignificant dependence on mass flux and vapor quality. The frictional pressure drop increased with mass flux and vapor quality and decreased with increasing saturation temperature as expected. Signs of dryout first appeared at vapor qualities of 85%, with the values generally increasing with increasing mass flux. The effect of varying system pressure was insignificant. The experimental results (boiling heat transfer, pressure drop and dryout heat flux) were compared with the predictions from well-known correlations (for macro and micro-scale channels) from the literature.