自然空化尾空泡内超声速射流流场特性数值研究仿真

Numerical Simulation of Flow Field Characteristics of Supersonic Jet in Natural Cavitating Tail Cavity

为揭示自然空化尾空泡内超声速流场的演化规律与空泡内部的流场结构,文中基于限体积法流体体积多相流模型,对自然空化尾空泡内超声速射流流场展开仿真研究,对比了不同空化数和来流攻角下的空泡内部流场参数分布,得出如下结论:自然空化尾空泡在超声速射流入射后,空泡形态较稳定,其演化主要集中在空泡尾部闭合处;空泡内超声速射流流场发展主要受回射流影响,无来流攻角时受回射流冲击,射流轴向发展受抑,轴向射流出现“回缩”现象,有来流攻角时,回射流位置发生偏移,其剪切卷吸作用占主导,射流轴向发展迅速;航行器姿态的稳定性主要受来流冲击和表面高压区分布的影响,空化数较小时,增大来流攻角可大幅度增加航行器俯仰力矩。

In order to reveal the evolution law of the supersonic flow field in the natural cavitating tail cavity and the flow field structure in the cavity,this paper simulated the flow field of the supersonic jet in the natural cavitating tail cavity based on the volume of fluid(VOF)multiphase flow model.The paper compared the distribution of the flow field parameters in the cavity under different cavitation number and different angles of attack of incident flow,and drew the following conclusions:The cavity shape of the natural cavitating tail cavity is relatively stable after the incident flow of the supersonic jet,and its evolution is mainly concentrated in the closure of the cavity tail.The development of the flow field of the supersonic jet in the cavity is mainly affected by the re-entrant jet.When there is no angle of attack of incident flow,the flow field is impacted by the re-entrant jet,and the axial development of the jet is suppressed.The axial jet appears retracted phenomenon.When there is an angle of attack of the incident flow,the position of the re-entrant jet has shifted,and the shear and suction effect is dominant.The axial development of the jet is rapid,and the stability of the attitude of the vehicle is mainly affected by the impact of the incident flow and the distribution of the surface high-pressure area.When the cavitation number is small,increasing the angle of attack of the incident flow can greatly increase the pitching moment of the vehicle.