喷水系统对W形地下空间热发射流场的影响

Influence on Flow Field of Hot Launch in a W-Shaped Underground Space by Water Injection

采用喷水系统改善导弹地下空间热发射过程的流场,以达到削减压力脉冲峰值、缓解压强振荡和降低流场温度的目的,即减压、降温。结合三维黏性可压缩Navier-Stokes方程、Mixture多相流模型和相变模型,建立气-液两相流控制方程组,并用燃气射流缩比试验数据验证数学模型和数值方法的有效性,采用计算流体力学数值计算方法分析喷水系统对导弹地下空间发射过程流场环境的影响。研究结果表明:在W形地下空间底部建立喷水系统,可以很好地改善导弹地下热发射过程空间内流场环境特性;喷水系统对初始超压现象有很好地抑制效果,弹底压强振荡由8次减少到4次,压强没有产生剧烈振荡,在1 atm上下缓慢变化,最大压强仅为1.20×10^(5)Pa左右,大大削减了初始超压峰值,并降低了压强振荡的频率和幅值,实现了减压效果;通过液态水剧烈汽化、动量交换等过程,喷水系统强烈而有效地抑制了燃气反溅现象,燃气被约束在筒底位置,导弹底部的最高温度从3000 K降低到了400 K左右,实现了降温效果。

The water spray system is used to improve the flow field in the thermal launch process of missiles in underground spaces,with the aim of reducing the peak value of pressure pulse,alleviating pressure oscillation,and reducing the temperature of flow field through“decompression and cooling”.In this study,a gas-liquid two-phase flow control equation is established by combining the three-dimensional viscous compressible Navier-Stokes equation,mixture multiphase flow model,and phase change model.The mathematical model and numerical method are validated using gas jet scaling test data.Computational fluid dynamics(CFD)numerical calculation method is used to analyze the influence of the water spray system on the flow field environment during the missile s underground space launch process.The results show that the environmental characteristics of the flow field in the underground space during the thermal launch of the missile are effectively improved by establishing a water spray system at the bottom of the W-shaped underground space.The water spray system has a good suppression effect on the initial overpressure phenomenon.The bottom pressure oscillation is reduced from 8 times to 4 times.The pressure changes slowly up and down at 1 atm,with the maximum pressure only about 1.20×10^(5)Pa.The initial overpressure peak is reduced,and the frequency and amplitude of the pressure oscillation are reduced,achieving the decompression effect.Through the process of violent vaporization of liquid water and momentum exchange,the phenomenon of gas backsplash is strongly and effectively suppressed by the water spray system.The gas is confined at the bottom of the cylinder,and the maximum temperature at the bottom of the missile is reduced from 3000 K to about 400 K,achieving the“cooling”effect.