水下火炮气幕式发射过程中燃气射流与液体工质相互作用特性研究

为了研究水下火炮气幕式发射过程中燃气射流与液体工质相互作用的特性，设计了可视化模拟实验装置，采用高速录像系统记录了圆柱形充液室中弹丸运动及气体与液体相互作用的过程特性，得到了弹丸速度与气幕轴向扩展速度随时间的变化关系。对比不同喷射参数条件下实验结果可以发现：弹丸运动速度随着喷射压力的增加而增加；气幕减阻性能随着斜面喷孔尺寸增大得到提升，弹丸运动速度随之增大。在实验基础上，建立了弹丸运动条件下多股燃气射流在液体介质中扩展的三维非稳态数学模型。针对实验工况进行数值模拟，模拟结果中多股燃气射流扩展过程与实验结果一致；对比二者气幕顶部轴向扩展位移值，可以发现计算结果与实测值吻合较好。弹丸运动条件下气幕生成的数值模型的建立，为水下火炮发射过程中身管内气幕生成及减阻机理分析提供了参考。

Research on Gas-liquid Interaction Characteristics during the Gas Curtain Launching Process of Underwater Gun

A visualization simulator is designed to understand the characteristics of interaction between combustion gas jet and liquid medium during the gas-curtain launching process of underwater gun. A high speed video camera system is used to record the motion of projectile in a cylindrical liquid-filled chamber and the gas-liquid interaction process. The flying velocity of projectile and the axial expanding speed of gas curtain are acquired in experiment. Experimental results show that the projectile velocity increases with the increase in injection pressure. With the increase in sizes of oblique nozzles, the drag reduction property of gas curtain is improved, and the projectile velocity is also increased. On the base of experimental study, an unsteady three-dimensional mathematical model is developed to simulate the expansion of multi-combustion gas jets in liquid medium. And a numerical simulation is carried out. The simulated expansion process of the multi-gas jets is consistent with the experimental result, and the axial displacement of simulated gas curtain is in a good agreement with the experiment data. The proposed numerical model provides a reference for the analysis of generation mechanism of gas curtain during launching.