水下爆炸引起的近自由面空化机理研究  

Research on mechanism of cavitation near free surface induced by underwater explosion

作　　者：余俊[1,2] 刘建湖 盛振新[1] 严波[1] 张显丕[1] Jun Yu;Jian-hu Liu;Zhen-xin Sheng;Bo Yan;Xian-pi Zhang(China Ship Scientific Research Center,Wuxi 214082,China;Taihu Laboratory of Deep-sea Technology Science,Wuxi 214082,China)

机构地区：[1]中国船舶科学研究中心,无锡214082 [2]深海技术科学太湖实验室,无锡214082

出　　处：《水动力学研究与进展（A辑）》2022年第4期483-491,共9页Chinese Journal of Hydrodynamics

摘　　要：水下爆炸过程中总会伴随有空化的产生,空化运动对于冲击波传播、爆炸气泡脉动以及周围结构物变形与损伤都会产生重要的影响。该文针对水下爆炸引起的近自由面空化现象,采用液-汽-空气-爆炸气体等多相可压缩流体模型,并结合相变转换模型来处理液相与汽相之间物质和热量的交换。该系统的控制方程采用分步法处理,首先利用二阶MUSCL-Hancock重构格式和HLLC近似黎曼求解器来求解齐次双曲型方程,再采用牛顿迭代法求解相变方程。利用一维激波管问题上对计算模型中的相变转换以及激波的捕捉能力进行了数值考核。针对水下爆炸引起的近自由面空化现象,首先在一维平面模型中对空化机理进行了探索,观察到了水中空泡在溃灭过程中出现的明显分层现象;然后利用二维轴对称模型模拟了水下爆炸引起的近自由面空化完整过程,发现在空化的演化过程中会出现涡环及其不断向外扩展的现象,数值模拟获得的空化域形态及其运动过程与试验观测基本一致。从流场中部分测点的压力时程曲线来看,相变模型对于早期冲击波阶段压力载荷的影响较小,而对空泡溃灭阶段的压力载荷有一定的影响。数值模拟结果初步证明了基于相变转换的空化计算模型能够有效预测水下爆炸引起的近自由面空化的产生、发展及其溃灭过程,为水下爆炸空化效应的深入研究提供了重要参考。Cavitation will always be accompanied in underwater explosion(UNDEX),and the movement of cavitation plays an important impact on shock wave propagation,explosion bubble pulsation and deformation and damage of surrounding structures.In this paper,liquid-vapor-air-explosion gas multiphase compressible fluids are used to analyze the cavitation near free surface in underwater explosion,which includes mass and heat transfer between liquid and vapor phases.The control equations of system are solved using a fractional step.The homogenous hyperbolic system is solved by second order MUSCL-Hancock reconstruction scheme and HLLC approximate Riemann solver f irstly,and then Newton iterative method is used to deal with the phase transition relaxation model.The phase transition and shock wave capture models are evaluated in 1D shock wave tube test.For the cavitation induced by underwater explosion near free surface,1D plane model is explored and spallation phenomenon of cavitation during collapse is observed.Then,2D axisym metric model is used to simulate underwater explosion cavitation near free surface,and vortex ring formed by cavitation and its external expansion can be obtained,which is in good agreement with experimental results.It can be observed from the pressure time history of some measuring points in flow that the phase transition model has little effect on the load in the early stage of sh ock wave,but has a certain influence on the load in the stage of bubble collapse.It is preliminarily proved that the numerical mo del can effectively predict the occurrence of creation,development and collapse of cavitation near free surface in underwater e xplosion,which could provide an important reference for the further research on underwater explosion cavitation effect.

关 键 词：相变转换模型 多相可压缩流体 水下爆炸 空泡溃灭 

分 类 号：O359[理学—流体力学] O345[理学—力学] O383