基于6DOF的高速射弹入水超空泡特性研究

根据非定常不可压缩流动的N-S方程和k-epsilon湍流模型,利用VOF多相流模型和Schnerr-Sauer空化模型,采用6DOF动网格,对反鱼雷射弹的入水过程进行了仿真。主要研究了两种具有不同空化器形状的射弹分别在入水角为30°和60°的工况下超空泡的形态和发展过程,以及阻力系数的变化情况。将仿真得到的空泡轮廓同经验公式计算结果进行对比,将仿真所得的弹体运动速度同在靶场进行实弹射击的测速结果进行对比,论证仿真程序的可靠性。结果表明:仿真结果与经验公式计算结果、实弹射击结果吻合程度较好,仿真成果可靠性较高;空化器形状对于阻力系数的大小有较大影响,入水角度对阻力系数的变化趋势有较大影响;弹体完全入水后升力系数、阻力系数因尾拍扰动而在一定范围内振荡,大入水角下弹体尾翼对水面的撞击较小入水角下剧烈。研究结果可为进一步研究反鱼雷射弹结构和超空泡射弹的优化提供必要参考。

Research on Entry Water Upercavitation Characteristics of High Speed Projectile Based on 6DOF

According to Navier-Stokes equation and k-epsilon turbulence model of unsteady incompressible flow, the water entry process of anti-torpedo projectile is simulated by using the VOF multiphase flow model, Schnerr-Sauer cavitation model and 6 DOF dynamic mesh. A study was made of the changes of drag coefficient and the supercavitations’ shapes and developmental process of projectile with different head types under the conditions of water inflow angle of 30° and 60° respectively. In this paper, not only a comparison of simulation results was made with empirical formula calculation, but also a comparison with measured results of live ammunition firing in X Range were made. The results show that the simulation results are in good agreement with the the calculated results of empirical formula and the live-shot results, with the reliability of the simulation results being high. The shape of cavitator has greater influence on the drag coefficient, and the angle of inflow has a greater influence on the change trend of drag coefficient. The lift coefficient and drag coefficient oscillate in a certain range due to the tail beat disturbance after the full inflow of the projectile. The impact of the projectile tail on the water surface at the lower angle of inflow is more intense than that at the lower angle of inflow. The results can provide necessary references for further research on optimization of anti-torpedo projectile structure and supercavitation projectile.