Numerical Simulation of Cavitation Bubble Growth within a Droplet
Numerical Simulation of Cavitation Bubble Growth within a Droplet
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DOI：
10.1017/jmech.2015.57
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发表时间：
2016-04
影响因子：
1.7
通讯作者：
M. Lü;Z. Ning;K. Yan;J. Fu;C.-H. Sun
中科院分区：
文献类型：
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作者：
M. Lü;Z. Ning;K. Yan;J. Fu;C.-H. Sun
空化气泡始终存在于离开喷嘴的柴油射流和因喷嘴内柴油超空化而从射流中破裂的柴油液滴中，部分由于两相混合物而增加了射流和液滴的不稳定性，但这种效应的机制仍不清楚。基于流体体积法(VOF)对柴油液滴内的空化气泡膨胀进行数值模拟，并利用Rayleigh-Plesset方程分析了气泡生长过程的控制机制。气泡长大过程分为表面张力控制域、综合竞争控制域和惯性力控制域三部分。在第一阶段，空化气泡的生长受到表面张力的控制，表面张力的减小导致气泡生长速率的增加。第二阶段，气泡的生长速度受表面张力、惯性力和粘性力的综合竞争控制。第三阶段，气泡长大过程主要受惯性力控制。
Cavitation bubbles, which always exist in the diesel jet leaving the nozzle and in diesel droplets breaking up from the jet as a result of supercavitation of the diesel within the injection nozzle, increase the instability of jet and droplets in part due to the two-phase mixture, while the mechanism of this effect is still unclear. Cavitation bubble expansion within the diesel droplet has been simulated numerically based on the volume of fluid (VOF) method, and the control mechanism of bubble growth process is analyzed by Rayleigh-Plesset equation. The process of bubble growth is divided into three parts, including surface tension controlled domain, comprehensive competition controlled domain and inertial force controlled domain. During the first stage, cavitation bubble growth is controlled by the surface tension, and the decrease of the surface tension leads to the increase of the bubble growth rate. During the second stage, the bubble growth rate is controlled by the comprehensive competition of the surface tension, the inertial force and the viscous force. During the third stage, the process of bubble growth is majorly controlled by the inertial force.