Numerical analysis of nucleate boiling in rolling rod bundle with tilted axis using two-fluid modeling approach

In this study, an Eulerian-Eulerian two-fluid approach was applied to simulate nucleate boiling in a verti-cal rolling 2 x 2 rod bundle with a tilted axis. For this purpose, the standard multiphaseEulerFoam solver of OpenFOAM was modified to include the fictitious forces necessary in a non-inertial frame of the ref-erence formulation. High-performance computing was then applied to analyze the effects of oscillation on boiling and the physics of the fluids inside the rod bundle. In particular, the effect of a tilted rolling axis was investigated for the first time. The results indicated that the space-averaged void fraction and surface-averaged heat transfer coefficient decrease in the rolling cases compared with the stationary case. Furthermore, it was found that while the tilt angle has a negligible effect on the space-averaged values, it may have a significant impact on the maximum value of the void fraction. The higher the tilt of the rolling axis, the higher the variation in the maximum field values. The results of this study will further improve our understanding of wall nucleate boiling, which is critical for the design, development, and safety of light water-cooled reactors (LWR).(c) 2022 Elsevier Ltd. All rights reserved.

Automated summary

In this study, an Eulerian-Eulerian two-fluid approach was used to simulate nucleate boiling in a vertical rolling 2 x 2 rod bundle with a tilted axis. The effects of oscillation on boiling and the physics of the fluids inside the rod bundle were analyzed using high-performance computing. The study investigated the effect of a tilted rolling axis for the first time and found that it affects the void fraction and heat transfer coefficient, with a higher tilt resulting in greater variation in the maximum field values. The results contribute to our understanding of wall nucleate boiling, important for the design and safety of light water-cooled reactors (LWR).