NUMERICAL SIMULATION OF BUBBLE DYNAMIC UNDER OCEAN CONDITIONS

摘要

In recent years, nuclear power are widely used in the ship and submarine. Affected by the ocean wave, the bubble dynamic under ocean conditions may be different from stationary condition. In order to investigate the influence mechanism of ocean conditions, the single bubble rising in stagnant liquid under rolling conditions with different frequencies and amplitudes were calculated through CFD method. In present work, the typical ocean conditions such as rolling were realized through dynamic mesh method, this method could simulated the movement of container directly. The Volume-of-fluid (VOF) method was applied to track the interface between liquid and gas phases and the surface tension were calculated by Continuum Surface Force (CSF) method. We can draw the conclusions as follows: (1) the bubble tend to move laterally and periodically under rolling conditions, this may attributed to the additional force caused by rolling motion. (2) the period of lateral movement are in accordance with the rolling period ,and the frequency and amplitude of bubble lateral movement may increasing as the decreasing of rolling period. (3) The amplitude of the bubble lateral displacement is proportional to the rolling amplitude. (4)larger bubbles have the higher rising velocity than the small ones, and the larger bubble are easier to break up which may promote the lateral movement.