旁泄间隙对燃气弹射内弹道特性影响

Influence of bypass clearance on gas-ejection internal ballistic characteristics

为了研究旁泄间隙(发射筒与隔板的间隙)对燃气弹射内外流场及内弹道特性参数的影响,采用Realizableκ-ε湍流模型,结合动态分层动网格及用户自定义函数(user defined function,UDF)技术,对燃气弹射过程进行了数值模拟,分析了旁泄间隙大小对燃气弹射性能的影响,并进行了地面发射试验。通过与试验数据对比,验证了燃气弹射仿真模型的有效性。仿真结果表明,在旁泄间隙出口附近形成明显漩涡,旁泄间隙的增大会导致低压室压力与加速度峰值减小,并使试验弹出筒时间延长、出筒速度降低,但变化趋势呈现非线性特征。旁泄间隙从2 mm增大到6 mm时,出筒时间延长7.7%,出筒速度降低16.3%,可认为在此范围内旁泄间隙的影响幅度相对较小;但此后旁泄间隙的影响会显著增强,当旁泄间隙从6 mm增大到8 mm时,出筒时间延长20%,出筒速度降低35.8%,当旁泄间隙增大到10 mm时,试验弹到筒口速度甚至降为0 m/s。本文研究结果为燃气弹射装置的设计与优化提供参考借鉴。

In order to study the influence of bypass clearance(the clearance between the launcher and the Missile pallet)on the flow fields and characteristic parameters of the gas ejection,realizable turbulence model,dynamic layered dynamic grid and user-defined function technology were used to simulate the process of gas ejection.And the influence of the bypass clearance size on the performance of gas ejection was analyzed.The ground launch test was carried out.Compared with the test data,the effectiveness of the gas ejection simulation model was verified.The simulation results showed that,obvious vortices were formed near the exit of the clearance.As the clearance increased,the pressure in the low-pressure chamber decreased,the acceleration peak decreased,the exit time of missile prolonged and the exit velocity decreased.When the clearance increased from 2 mm to 6 mm,the exit time was only extended by 7.7%,and the exit speed was reduced by 16.3%,the change of exit time and velocity was relatively small within this clearance range.When the clearance increased from 6 mm to 8 mm,the exit time was extended by 20%,and the exit velocity was reduced by 35.8%.When the clearance increased to 10 mm,the ejection of missile failed,and the exit time and velocity changed significantly within this clearance range.The research results provide an important guidance for the optimization design of gas ejection device.