Interface Tracking Investigation of Geometric Effects on the Bubbly Flow in PWR Subchannels
Interface Tracking Investigation of Geometric Effects on the Bubbly Flow in PWR Subchannels
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DOI：
10.1080/00295639.2018.1499280
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发表时间：
2018-08
影响因子：
1.2
通讯作者：
J. Fang;J. Cambareri;M. Rasquin;A. Gouws;R. Balakrishnan;K. Jansen;I. Bolotnov
中科院分区：
文献类型：
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作者：
J. Fang;J. Cambareri;M. Rasquin;A. Gouws;R. Balakrishnan;K. Jansen;I. Bolotnov
摘要水作为冷却剂在压水堆燃料棒束中吸收燃料棒表面的热量，会发生过冷沸腾。由于浮力效应，所产生的蒸汽气泡然后将沿着上升并与子通道几何形状相互作用。气泡行为的可靠预测对于保证反应器安全稳定运行具有重要意义。然而，考虑到像核反应堆这样的复杂工程系统，在反应堆运行条件下进行高分辨率测量来研究气泡流是非常具有挑战性的（如果不是不可能的话）。缺乏基本的两相流数据库阻碍了更先进的反应堆设计所需的精确两相流模型的开发。为了应对这一挑战，基于第一性原理的数值模拟正在成为一个有吸引力的替代方案，以产生一个补充的数据源沿着实验。利用最先进的超级计算机提供的前所未有的计算能力，直接数值模拟（DNS），加上界面跟踪方法，正在成为一个实用的工具，调查一些最具挑战性的工程流问题。在所提出的研究中，通过DNS模拟带有辅助结构（例如，支撑定位格架和混合叶片）。这些结构施加的泡状流的几何效果进行了研究与传统的时间平均方法和一种新的动态气泡跟踪方法。获得的新见解将有助于为更好的两相模型提供信息，从而有助于实现更安全、更高效的核反应堆系统。
Abstract Absorbing heat from the fuel rod surface, water as coolant can undergo subcooled boiling within a pressurized water reactor (PWR) fuel rod bundle. Because of the buoyancy effect, the vapor bubbles generated will then rise along and interact with the subchannel geometries. Reliable prediction of bubble behavior is of immense importance to ensure safe and stable reactor operation. However, given a complex engineering system like a nuclear reactor, it is very challenging (if not impossible) to conduct high-resolution measurements to study bubbly flows under reactor operation conditions. The lack of a fundamental two-phase-flow database is hindering the development of accurate two-phase-flow models required in more advanced reactor designs. In response to this challenge, first-principles–based numerical simulations are emerging as an attractive alternative to produce a complementary data source along with experiments. Leveraged by the unprecedented computing power offered by state-of-the-art supercomputers, direct numerical simulation (DNS), coupled with interface tracking methods, is becoming a practical tool to investigate some of the most challenging engineering flow problems. In the presented research, turbulent bubbly flow is simulated via DNS in single PWR subchannel geometries with auxiliary structures (e.g., supporting spacer grid and mixing vanes). The geometric effects these structures exert on the bubbly flow are studied with both a conventional time-averaging approach and a novel dynamic bubble tracking method. The new insights obtained will help inform better two-phase models that can contribute to safer and more efficient nuclear reactor systems.