Experimental study on single bubble growth of R32+R1234yf binary mixtures during saturated pool boiling
Experimental study on single bubble growth of R32+R1234yf binary mixtures during saturated pool boiling
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DOI：
10.1016/j.applthermaleng.2022.119535
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发表时间：
2022-10
影响因子：
6.4
通讯作者：
Jingwen Li;Zhen Yang;Yuanyuan Duan
中科院分区：
文献类型：
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作者：
Jingwen Li;Zhen Yang;Yuanyuan Duan
R32 + R1234 yf混合物被认为是非常有前途的制冷剂。了解混合物的气泡生长特性对于了解其沸腾传热性能至关重要。在这项研究中，池沸腾实验进行了研究的单气泡增长特性的R32，R1234 yf，以及它们的二元混合物。在1.3- 6.2K的温度范围内，得到了每种试验制冷剂的气泡生长曲线.结果表明，纯制冷剂的渐近气泡生长速率慢于使用以前的理论模型，其中开发的孤立气泡在无限过热液体中的增长预测。混合物的气泡生长常数低于纯组分的气泡生长常数，而气泡生长指数大于“理想生长指数”。有效壁厚的突然减小和传质阻力的急剧增加减缓了初始气泡的生长速率。在后期的增长阶段，尚未干燥的微层提供了稳定的热输入的气泡，导致在一个更高的渐近增长率比纯组件。提出了一组混合物气泡增长速率的无量纲关联式，并在± 15%的偏差范围内预测了本研究中的数据。
R32 + R1234yf mixtures are considered highly promising refrigerants. Understanding the bubble growth characteristics of mixtures is vital for understanding their boiling heat-transfer performance. In this study, pool boiling experiments were conducted to investigate the single-bubble growth characteristics of R32, R1234yf, and their binary mixtures. The bubble growth curves for each test refrigerant were obtained in the superheat range of 1.3–6.2 K. The results showed that the asymptotic bubble growth rates of the pure refrigerants were slower than those predicted using previous theoretical models, which were developed for isolated bubbles growing in an infinite superheated liquid. The bubble growth constants of the mixtures were lower than those of the pure components, whereas the growth exponents were greater than the “ideal growth exponent.” The sudden decrease in the effective wall superheat and sharp increase in mass transfer resistance slowed the initial bubble growth rate. In the late stage of growth, the microlayer that had not yet dried out provided stable heat input to the bubble, resulting in a higher asymptotic growth rate than that of pure components. A set of dimensionless correlations for the bubble growth rate of mixtures is proposed, and they predicted the data in this study within a ± 15% deviation band.