水下超声速气体射流的初始流动特性研究  

Initial flow characteristics of an underwater supersonic gas jet

作　　者：张焕好[1] 郭则庆[1] 王瑞琦[1] 陈志华[1] 黄振贵[1] ZHANG Huanhao;GUO Zeqing;WANG Ruiqi;CHEN Zhihua;HUANG Zhengui(National Key Laboratory of Transient Physics, Nanjing University of Science and Technology, Nanjing 210094, China)

机构地区：[1]南京理工大学瞬态物理国家重点实验室,南京210094

出　　处：《振动与冲击》2019年第6期88-93,131,共7页Journal of Vibration and Shock

基　　金：国家自然科学青年基金(11502117);瞬态物理国家重点实验室基金(614260403041802)

摘　　要：为研究水下发射过程中高温高压火药燃气喷射进入液相水过程的流体形态变化与流动特性,采用Mixture多相流模型与蒸发与凝结模型建立了二维轴对称水下超声速气体射流的数值计算模型并进行了相关的数值模拟,得到水下超声速气体射流的初始流动结构。数值结果表明,超声速气体与水介质的强撞击会在气液界面上形成一个强压缩区,且连续撞击形成的压力波反传,使喷管出口射流核心区流场出现周期性脉动。因气液界面上的强剪切作用,而在气液混合区内形成复杂的小激波结构,小激波结构的出现加速了气液界面的失稳,从而促进了气液掺混效应。另外,在气泡内会形成典型的欠膨胀射流结构,因而气泡内的流动特征与单相超声速气体射流情况类似。To investigate the evolution and the characteristics of flow structures during the high-pressure and high-temperature propellant gases injecting into water in the launching process of an underwater gun, a two-dimensional axis-symmetric model of the underwater supersonic gas jet was established via the Mixture model and Evaporation-condensation model. A relative numerical simulation was conducted and the initial flow structure of the underwater supersonic gas jet was obtained. The numerical results illustrate that a highly pressed region forms on the gas-liquid interface due to the strong impact between the supersonic gas and water, and the continual impact generates the reflection of the pressure wave, which causes periodic impulses in the core flow region at the nozzle’s exit. In addition, complex shocklets structures form in the gas-liquid hybrid region due to the strong shear effect on the gas-liquid interface, which accelerates the instability of the gas-liquid interface and promotes the gas-liquid mixing effect. Moreover, the typical underexpanded jet structure forms inside the bubble, whose flow characteristic is similar to that of a single phase supersonic gas jet.

关 键 词：水下超声速气体射流 气液两相流 气泡运动 小激波 数值模拟 

分 类 号：O358[理学—流体力学]