Simulating on the Condensing of One Freon Bubble in a Subcooled Pool With MPS-MAFL
Moving-Particle Semi-implicit method (MPS) is a gridless method to simulate two phase flows developed by The University of Tokyo. Different with traditional grid codes such as finite volume method, finite difference method, MPS could trace the two-phase interface acutely. There is no grid to simulate two-phase fluid in MPS, for the fluid is replaced by particles with very small volume, while grid plays an important role in traditional code. The gas-liquid interface could be simulated with more detail by particles reacting and solving equations of energy, emotion and continuity. In MPS-MAFL, the calculating phases are divided into three parts: Lagrangian, re-configuration and convection (Eulerian). The calculating has been improved by solving equations semi-implicitly. In the study, MPS-MAFL is used to simulate the phenomena of small and larger Freon bubbles condensing in a subcooled pool as high temperature steam will inject into a subcooled pool after some accident happens for a PWR or a Super Critical Water Reactor. The sensitivity on pool subcooling and on non-condensable gas fraction of a small bubble is also studied here to understand the condensation behavior and the shape verifying of a large bubble condensing is given. The simulating shows that the bubble pressure decreases as the condensation begins with the shrinking of the interface while at the later phase of the condensation, the bubble pressure becomes larger than that of the circumstance. A peak pressure will emerge at the moment that the bubble collapses and there will be a maximum pressure value at a certain subcooling. As the subcooling increases or decreases, the peak pressure will drop and may fade away. The maximum pressure is 3.12MPa at a subcooling about 20℃.When there is non-condensable gas in the bubble, it may rise out of the pool before collapsing or there is no collapsing. But there would appear a pressure pulse when the bubble shrinks to the minimum size. And for a small bubble, there would be a maximum pressure pulse when the non-condensable gas fraction is about 0.11％. For a large bubble condensing in a pool with a subcooling of 20K, it will split before the condensation process ended.
MPS-MAFL Freon R113 bubble condensation non-condensable gas
Minggang Lang
State Nuclear Power Technology Research & Development Centre Institute of Nuclear and New Energy Technology, Tsinghua University 100084, Beijing, P. R. China
国际会议
上海
英文
869-884
2010-10-10（万方平台首次上网日期，不代表论文的发表时间）