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Assessment of void fraction models and correlations for subcooled boiling in vertical upflow in a circular tube
International Journal of Heat and Mass Transfer ( IF 5.0 ) Pub Date : 2021-02-23 , DOI: 10.1016/j.ijheatmasstransfer.2021.121060
Chang Cai , Issam Mudawar , Hong Liu , Xi Xi

This paper provides a comprehensive review as well as assessment of accuracy of published models and correlations for net vapor generation point, vapor quality, and void fraction in subcooled vertical upflow boiling in a circular tube. Also provided is a detailed discussion on the rationale and physical mechanisms upon which the individual predictive methods are based. The assessment is accomplished by comparing predictions to a new consolidated database consisting of 61 data points for thermodynamic equilibrium quality at the net vapor generation point, amassed from 5 sources, and 1118 data points for void fraction, from 11 sources. Overall, it is shown that correlations by Saha and Zuber provide best predictions for both thermodynamic equilibrium quality at the point of net vapor generation and axial distribution of vapor quality. In terms of void fraction prediction, best accuracy among prior predictive methods is achieved, in order, using a slip ratio model by Thom, drift-flux model by Dix, slip ratio model by Ahmad, and modified homogeneous model by Nishino and Yamazaki. It is shown that the vast majority of models and correlations show far better accuracy over the higher range of void fraction of 0.20-1.0 than the low range of 0-0.2. A new and simple void fraction correlation spanning the entire range of flow conditions of the consolidated database is proposed, which is shown to yield superior overall predictive accuracy compared to prior models and correlations. Finally, a step-by-step procedure for calculating void fraction with best accuracy is presented.



中文翻译:

圆管垂直上升流中过冷沸腾的空隙率模型及其相关性的评估

本文提供了全面的综述,并评估了已发布模型的准确性以及圆形管中过冷垂直上升流沸腾中净蒸气产生点,蒸气质量和空隙率的相关性。还提供了有关各个预测方法所基于的原理和物理机制的详细讨论。评估是通过将预测与新的合并数据库进行比较而完成的,该数据库包含来自5个来源的61个净蒸汽产生点热力学平衡质量数据点和1118个11个来源的空隙率数据点。总体而言,已表明,萨哈(Saha)和祖伯(Zuber)的相关性为净蒸汽产生点和蒸汽质量轴向分布方面的热力学平衡质量提供了最佳预测。在空隙率预测方面,依次使用Thom的滑移率模型,Dix的漂移-通量模型,Ahmad的滑移率模型以及Nishino和Yamazaki的改进的均匀模型,可以在现有的预测方法中获得最佳的准确性。结果表明,绝大多数模型和相关性在0.20-1.0的较高空隙率范围内显示出比0-0.2的较低范围更好的精度。提出了一个新的简单的空隙率相关性,该相关性跨越了合并数据库的整个流动条件范围,与以前的模型和相关性相比,它显示出更高的总体预测精度。最后,介绍了以最佳精度计算空隙率的分步过程。使用Thom的滑移率模型,Dix的漂移通量模型,Ahmad的滑移率模型以及Nishino和Yamazaki的改进的均质模型。结果表明,绝大多数模型和相关性在0.20-1.0的较高空隙率范围内显示出比0-0.2的较低范围更好的精度。提出了一种新的简单的空隙率相关性,该相关性跨越了合并数据库的整个流动条件范围,与以前的模型和相关性相比,该方法显示出更高的总体预测精度。最后,介绍了以最佳精度计算空隙率的分步过程。使用Thom的滑移率模型,Dix的漂移通量模型,Ahmad的滑移率模型以及Nishino和Yamazaki的改进的均质模型。结果表明,绝大多数模型和相关性在0.20-1.0的较高空隙率范围内显示出比0-0.2的较低范围更好的精度。提出了一种新的简单的空隙率相关性,该相关性跨越了合并数据库的整个流动条件范围,与以前的模型和相关性相比,该方法显示出更高的总体预测精度。最后,介绍了以最佳精度计算空隙率的分步过程。结果表明,绝大多数模型和相关性在0.20-1.0的较高空隙率范围内显示出比0-0.2的较低范围更好的精度。提出了一个新的简单的空隙率相关性,该相关性跨越了合并数据库的整个流动条件范围,与以前的模型和相关性相比,它显示出更高的总体预测精度。最后,介绍了以最佳精度计算空隙率的分步过程。结果表明,绝大多数模型和相关性在0.20-1.0的较高空隙率范围内显示出比0-0.2的较低范围更好的精度。提出了一种新的简单的空隙率相关性,该相关性跨越了合并数据库的整个流动条件范围,与以前的模型和相关性相比,该方法显示出更高的总体预测精度。最后,介绍了以最佳精度计算空隙率的分步过程。

更新日期:2021-02-24
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