Pulse-Triggered Instability in Solid Rocket Motors

This paper presents the results of a study to assess the ability of a recently developed comprehensive nonlinear combustion instability model to predict pulse-triggered instability in solid rocket motors. Performance models were developed to calculate the mass and energy flow rates produced by three laboratory pulsers (pyro, low brisance, and piston). The mass and energy flow rates are utilized as boundary conditions for the comprehensive nonlinear combustion instability model. The model predicts the temporal and spatial evolution of the resulting waveforms (amplitude and harmonic content) in the combustion chamber. Comparisons of theoretical predictions with experimental data for both laboratory and full-scale motors are presented. Very good agreement is demonstrated between the predicted and measured pulse amplitudes, wave shapes, limiting amplitudes, mean pressure shifts, and growth rates.