关键词: 固体火箭发动机, 复合过载, 压强振荡, 声腔共振, 流动特性。

Abstract: Solid rocket motors often experience complex overload conditions during flight, and sudden internal ballistic lift or oscillations occur occasionally. In order to study the pressure characteristics in the combustion chamber of solid rocket motors under dynamic overload conditions, the relationship curves between overload and mass flow rate of propellant combustion surface are obtained according to the Greatrix burning rate enhancement model and the zero-dimensional internal ballistic model considering the combustion surface recession; based on the relationship, the internal flow field simulation is carried out in composite overload for a cylindrical cone bore charge. The effects of lateral overload acceleration, lateral vibration and vibration frequency on the dynamic characteristics of the motor and vortex flow are investigated. The results show that with the increase of lateral overload acceleration and lateral vibration, the equilibrium pressure rise and pressure oscillation amplitude in the combustion chamber increase, and the lateral overload accelera-tion can increase the pressure amplitude and equilibrium pressure by 0.02% and 0.35% per 1g increase in acceleration at the working pressure of 10.54MPa; with the lateral vibration frequency rise from 7Hz to 320Hz, the amplitude of pressure oscillation decreases. But it is amplified by resonance near the intrinsic frequency of the combustion chamber acoustic cavity, and the first-order resonance (160Hz) raises the amplitude of the pressure from 0.16% to 0.30%, which is twice as much as the original amplitude; When the composite overload frequency resonates with the combustion chamber acoustic cavity, the energy transfer from the propellant surface into the combustion chamber is more organized.

Key words: Solid Rocket Motors, Compound Overload, Pressure Oscillations, Acoustic Cavity Resonance, Flow Characteristics.