Abstract The present paper is Part Ⅱ of an investigation into void fraction measurement and modeling in a triangular-array rod bundle geometry under high-pressure conditions (P = 5–9 MPa and G = 100–350 kg m−2 s−1). In Part I of the study, the experimental facility and measurement techniques were described, and the measured local, chordal, and area-averaged void fractions were presented and analyzed. In this paper, six existing drift-flux models for rod bundles are assessed using the present data. Results show that most of the models are inconsistent with the measured void fraction under low void fraction conditions. This is because the effects of pressure and mass flux on drift-flux parameters are not considered. Hence, a new drift-flux model is developed with flow parameters and flow regime transition being considered. Additionally, the general applicability of this new model is verified by both the present data and existing data in the literatures. Results show that the new drift-flux model agrees well with the experimental data, with the relative deviations of void fraction less than 20%, indicating that the new model is applicable under a wide range of mass-flux conditions.

中文翻译：

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高压下棒束几何结构中的空隙分数——第二部分：漂移-通量模型评估和开发

摘要 本文是在高压条件下（P = 5-9 MPa 和 G = 100-350 kg m-2 s-1）三角阵列棒束几何结构中空隙率测量和建模研究的第二部分. 在研究的第一部分，描述了实验设施和测量技术，并介绍和分析了测得的局部、弦和面积平均空隙率。在本文中，使用现有数据评估了六种现有的棒束漂移通量模型。结果表明，在低空隙率条件下，大多数模型与测量的空隙率不一致。这是因为没有考虑压力和质量通量对漂移通量参数的影响。因此，开发了一种新的漂移通量模型，其中考虑了流动参数和流态转换。此外，现有数据和文献中已有的数据都验证了这种新模型的普遍适用性。结果表明，新的漂移-通量模型与实验数据吻合良好，空隙率的相对偏差小于20%，表明新模型适用于广泛的质量-通量条件。