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首页> 外文期刊>International Journal of Refrigeration >A new heat transfer coefficient correlation for pure refrigerants and near-azeotropic refrigerant mixtures flow boiling within horizontal microfin tubes
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A new heat transfer coefficient correlation for pure refrigerants and near-azeotropic refrigerant mixtures flow boiling within horizontal microfin tubes

机译：纯制冷剂和近共沸制冷剂混合物在水平微素管内流动沸腾的新传热系数相关性

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A new correlation is presented to predict the heat transfer coefficients (HTCs) of pure refrigerants and near-azeotropic refrigerant mixtures undergoing flow boiling within horizontal microfin tubes. This is accomplished by first putting together a 2622-point experimental database from 25 sources. The data includes CO 2, R12, R1234yf, R1234ze(E), R134a, R22, R32, R404A, and R410A, 2.1-14.85 mm fin root diameter tubes, -20 degrees C to 39.9 degrees C saturation temperatures, vapor qualities from 0 to 1, reduced pressures from 0.03 to 0.78, and heat and mass fluxes ranging from 1 to 58.7 kW/m(2) and 25 to 820 kg/s m(2), respectively. The entire database was randomly divided into two subsets, 90% of the data being used to develop the new correlation, with the remaining 10% used to validate it. The correlation was developed in two steps. Thirty-eight unique dimensionless parameters pertinent to flow boiling in microfin tubes were first selected. Multi-variable regression analysis was then applied to identify the most significant variables influencing the flow boiling Nusselt number. The new correlation was evaluated and compared with six extant correlations on an overall basis as well as for several bins of parameters. Overall evaluation for the entire database, for the 10% test data, and for points with experimental uncertainties less than +/- 17% shows that the new correlation is significantly better than any of the extant correlations. For these three overall assessments, the new correlation predicts 71.5-80.5% of the data within +/- 30% error bands, with a mean absolute deviation of 21.5 to 25.2%. Additionally, the distribution of the entire database and the performance of the new correlation was examined relative to refrigerant, and for various bins of fin root diameter, D-r, mass flux, G, all-liquid Reynolds number, Re-al, reduced pressure, P-R, saturation temperature, T-sat, heat flux q, and vapor quality, x. In general, the new correlation shows reasonably good predictions, which are better than those of the existing correlations for most parameter bins, with MAD values generally smaller than 35%. Based on the bin analysis, parameter ranges in which one of the extant correlations gives better predictions than the new correlation are also identified. With these exceptions in mind, the new correlation can be used as a reasonably reliable predictive tool for a large variety of refrigerants under different operating conditions of practical interest. (c) 2017 Elsevier Ltd and IIR. All rights reserved.
机译：提出了一种新的相关性以预测纯制冷剂的传热系数（HTC）和近共沸制冷剂混合物在水平微素管内进行的流动沸腾。这是通过首先将2622点实验数据库从25个源放在一起来实现的。数据包括CO 2，R12，R1234YF，R1234（E），R134A，R22，R32，R404A和R410A，2.1-14.85mm翅片直径管，-20℃至39.9摄氏度，蒸汽品质从0对于1，减少0.03至0.78的压力，以及分别为1至58.7 kW / m（2）和25至820kg / sm（2）的热量和质量通量。整个数据库随机分为两个子集，90％的数据用于开发新的相关性，其余10％用于验证它。相关性分两步开发。首先选择与Microfin管中的流动沸腾相关的三十八个独特的无量纲参数。然后应用多变量回归分析以确定影响流量沸腾露珠数的最重要的变量。评估新的相关性并与总体基础的六个远端相关性进行了比较，以及几个参数垃圾箱。整个数据库的整体评估，对于10％的测试数据，以及具有实验性不确定性的点小于+/- 17％的点表明，新的相关性明显优于任何远端相关性。对于这三种整体评估，新相关性预测了+/- 30％误差带内的数据71.5-80.5％，其平均绝对偏差为21.5至25.2％。另外，相对于制冷剂检查整个数据库的分布和新相关性的性能，以及针对翅片直径的各种垃圾箱，DR，质量磁通，G，全液体雷诺数，RE-Al，减压， PR，饱和温度，T-SAT，热通量Q和蒸汽质量，X。通常，新的相关性显示出合理的良好预测，这比大多数参数箱的现有相关性更好，疯的价值通常小于35％。基于BIN分析，还识别了其中一个远端相关性提供比新相关的更好预测的参数范围。通过考虑这些例外，新的相关性可以用作在不同操作条件下的各种制冷剂的合理可靠的预测工具。 （c）2017年Elsevier Ltd和IIR。版权所有。

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