【摘要】 本文计算了生长过程中的单气泡在自由流场和边界层流场中的运动和空化起始行为。计算中考虑了气体扩散、边界层的存在、水流与气泡的相对速度、湍流中的脉动、气泡的浮力等因素对气泡运动的影响,考虑了气泡在生长过程中的失稳破裂、汽液相变对气泡空化的影响、以及筛核效应、尺度效应。对气泡的运动和空化行为进行了较为详细的描述。更多还原

【Abstract】 This paper presents analyses and numerical calculation of a single bubble movement and its cavitation behavior, where the influence of air diffusion, boundary layer, pressure fluctuation, relative velocity between the bubble and the flow and the growing bubble burst effect are considered. The screening nuclei effect, scale effect and the evaporation affecting the bubble cavitation are also taken into consideration. The calculation results show that the main cause of bubble cavitation is the existence of a low pressure region around the bubble. The real critical radius of bubble cavitation RC is somewhat different from the static critical radius R*. When the initial radius R0 is small, RC>R*, and when R0 is big, RO<R*. Moreover, the air diffusion effect does not influence much on the free bubble cavitation, but it does influence a great deal on the cavitation of the bubble which attached to the body. Finaly, the existence of a boundary layer facilitates the occurrence of the bubble cavitation. And the bubble is quite possible to burst even during the process of bubble growth.更多还原