弹体穿越冰水混合物流动过程的数值模拟

Numerical Simulation of Flow Filed of Projectile Passing Through Ice Water Mixture

针对潜射导弹穿越冰水混合物的过程进行数值模拟。基于ANSYS/LS-DYNA商用软件,采用ALE算法,建立了冰的破碎模型,流体区域包含水与空气2种流体介质,水与空气采用NULL材料模型,水介质的状态方程采用Gruneisen状态方程。对细长弹体、冰体以及流体域进行建模,利用欧拉-拉格朗日耦合方法对弹体、冰体以及流体域进行流固耦合计算。对不同冰体分布方式(规则分布、菱形分布、随机分布)和不同弹体相对位置(冰体正下方、冰体间隙)的弹体出水过程进行对比计算研究,获得了弹体在穿越冰水混合物过程中流场的密度、压力、应力、速度随时间的变化规律,以及不同工况下的弹体质心位移情况。数值模拟结果表明:弹体在水下运动过程中空泡逐渐扩大,空化现象显著;流场应力的存在对弹丸运动产生一定的影响;不同冰体分布方式及初始弹体相对位置,会造成弹体质心位移不同。

The process of submarine launched missile passing through ice water mixture was studied by numerical simulation.Based on commercial software ANSYS/LS-DYNA and ALE algorithm,the ice breaking model was established.The fluid region included two kinds of fluid media,water and air.The NULL material model was used for water and air,and Gruneisen equation of state was used for water medium.The slender projectile,ice body and fluid domain were modeled,and the fluid structure coupling calculation of the missile body,ice body and flow field domain was carried out by using Euler Lagrangian coupling method.The process passing through water in different ice distribution patterns(regular distribution,rhombic distribution and random distribution)and different relative positions(under the ice body and between the ice bodies)were calculated and compared.The variation laws of the density,pressure,stress and velocity of the flow field with time and the displacement of the mass center under different working conditions were obtained.The simulation result shows that during the movement of projectile,the cavity gradually expands,and the cavitation is obvious.The flow field stress has some effects on the movement of projectile.Different ice-distributions and initial relative positions can lead to different displacements of projectile centroid.