Investigating the Acoustic Response Characteristics of a Solid Rocket Motor Combustor in High‐Temperature and High‐Pressure Environments

Abstract

AbstractWith the rapid development of aerospace technologies, coupling of pressure oscillations and unstable combustion in solid rocket motors has become a research hotspot in the past few years. In the present study, an experimental system is designed to investigate high‐pressure flows subjected to acoustic excitation. Then cold flow experiments and numerical simulations are carried out with different acoustic excitation frequencies, different background pressures, and different ambient temperatures. The pressure oscillation characteristics and the acoustic response characteristics of the combustion chamber in a high‐temperature and high‐pressure combustion chamber are analyzed. It is found that the frequency of the pressure oscillation inside the combustion chamber and the output excitation frequency of the signal generator are the same. When the excitation frequency is in the range of 50–200 Hz, the sound pressure amplitude corresponding to each test temperature increases with the increase of the frequency. Moreover, when the background pressure is in the range of 0–0.6 MPa, the sound pressure amplitude increases with the increase of the pressure. Meanwhile, there is no clear correlation between the sound pressure amplitude of the combustion chamber and temperature when the chamber temperature is in the range of 293–363 K. The obtained results from the numerical simulation are consistent with the experimental data and the relative error is less than 5.9 %, which verifies the accuracy of the model. The simulated sound pressure amplitude in the combustion chamber at high temperatures and high pressures is a cubic function of pressure and temperature. The present study is expected to provide an innovative way to investigate pressure oscillations and combustion instability of the propellant in the combustion chamber of solid rocket motors at high temperatures and high pressures.