推进系统参数变化对液体火箭纵向振动响应的影响分析

摘要

To optimize the propulsion system of liquid rockets and avoid the low frequency vibration environment deterioration of liquid rockets caused by POGO vibration,a dynamic model of POGO vibration system in liquid rockets was established,and a time domain model for analysing the sensitivity of longitudinal vibration response of liquid rockets (LVRLR)with respect to parameters of propulsion system was proposed based on the dynamic sensitivity technique. Numerical calculations,show that the variations of inertial parameters,drag parameters and stiffness parameters of the fluid and the variation of dynamic gain of the pump for propulsion system have important effects on LVRLR and their influences were analysed.The results show the sensitive extents of LVRLR with respect to the inertial parameters and the drag parameters of fluid are sharply greater than the stiffness parameters of fluid,the influence of the dynamic gain variation of pump on LVRLR is the maximum,and the influence of the variation of fluid stiffness in the short pipe at pump front on LVRLR is the minimum.The results provide references to the reduction of longitudinal vibration of liquid rockets and to the further study of the characteristics of POGO vibration.%为了优化液体火箭推进系统，避免 POGO 振动引起液体火箭低频振动环境恶化对火箭飞行过程的不利影响，建立了液体火箭 POGO 振动系统的动力学模型，利用动态灵敏度技术，提出了液体火箭纵向振动响应对推进系统参数的灵敏度时域分析模型。通过数值仿真，得到了推进系统流体惯性、阻力和刚度参数以及泵的动态增益变化对液体火箭纵向振动响应的影响规律。研究结果表明，液体火箭纵向振动响应对流体惯性和阻力参数的敏感程度比流体刚度参数明显大，泵动态增益的变化对液体火箭纵向振动响应的影响最大，泵前短管的流体刚度变化对液体火箭纵向振动响应的影响最小。为减小液体火箭纵向振动，进一步研究 POGO 振动特性提供参考。