火箭贮箱增压系统起动关闭过程压力冲击计算

为研究火箭贮箱增压系统起动、关闭瞬变过程中压力冲击的产生过程和传播规律,采用可应用于多种气体计算的拉格朗日坐标下的一维非定常气体运动方程有限差分格式求解管路流动,管路元件由反映其动态过程的常微分方程数值求解,气体摩擦损失使用准稳态公式计算.采用B-B(Beattie-Bridgeman)方程描述真实气体热力学关系.对某增压系统模型起动、关闭中包括压力冲击在内的动态过程进行了计算.计算表明:起动过程中,压力冲击变化大,压力振荡周期短、频率高、衰减迅速;关闭过程中,压力冲击变化小,压力振荡周期长、频率低、衰减缓慢.两种过程中都出现了高于气瓶增压压力的冲击压力峰值.数学模型和方法在火箭贮箱增压系统瞬变过程的计算中显示了较好的有效性. 

Simulation of pressure shock during start and shutdown operation of rocket tank pressurization system

For the purpose of researching into the engendering and diffusing of the pressure shock during the starting and the shutting of the rocket tank pressurization system,one-dimensional nonsteady finite difference equations under the Lagrange reference frame were built to simulate the gas flow in the pipes,and ordinary differential equations were calculated numerically based on the dynamic processes of the components,while the frictional loss was computed with a quasi-steady formula.The B-B(Beattie-Bridgeman) function was used to simulate the real-gas effect.The results were presented for the unsteady processes of a representative pressurization system,including the pressure shock that appeared during the starting and shutting operation.It is shown that the pressure shock during the starting changes with large amplitude and the pressure oscillation have shorter period,higher frequency,and rapidly cause of attenuation,while the pressure shock and oscillation changes reversely during the shutting operation.During both the operations,the pressure peak appeared was higher than the pressure in the bottle.The mathematical model and calculating method are validated to be effective in the calculation of the dynamic process of the rocket tank pressurization system.