Void fractions in a rod bundle geometry at high pressure-Part.: Drift-flux model assessment and development

摘要

The present paper is Part. 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. (C) 2020 Elsevier Ltd. All rights reserved.