浸没排气过程声信号与流场振荡规律研究

Study on acoustic signal and flow field oscillation in submerged air-jetting process

采用流体体积(Volume of Fluid,VOF)模型和威廉姆斯-霍金斯(Ffowcs Williams and Hawkings,FW-H)模型对浸没排气过程声信号进行数值模拟,研究竖直向下浸没排气过程声信号产生机制及理论依据。将模拟结果与实验结果进行对比,验证模型的适用性和准确性。研究结果表明,声信号与流场流动状态相关,气泡间分离和气体再注入过程引起的气泡体积剧烈振动是影响气泡流声信号产生的关键因素。在同一深度处,在径向上声压随位置的变化服从指数衰减,在周向上声信号呈现球源信号传播特点。

In order to analyze the acoustic signal of vertical downward air-jetting,the volume of fluid(VOF)model and Ffowcs Williams and Hawkings(FW-H)model are used to simulate the submerged gas air-jetting process.The accuracy of the selected model and the calculated results are verified by experiments.Based on the calculated flow field parameters,the generation mechanism and theoretical basis of acoustic signal are analyzed.The simulation results show that the flow field parameters have important effects on the acoustic signal.During vertical submerged downward air-jetting,the sound signal of bubble flow is significantly influenced by the considerable oscillation of bubble volume,which is caused by the bubble separation and air reinjection.At the same depth,sound pressure had the exponentially attenuates in the radial direction,and the acoustical signal around the circumference shows the characteristics of spherical source signal propagation.