NON-ACOUSTIC COMBUSTION INSTABILITY OF SOLID PROPELLANTS

Abstract : Non-acoustic combustion instability was examined in an uncatalyzed, a catalyzed, and two aluminized composite propellants. These propellants were studied, burning cigarette fashion, in a burner capable of operating at values of L* as small as 5 cm. It was observed that the frequency of the pressure oscillations varied with the value of L*, frequency decreasing with increaseing L*. The data were correlated by plotting frequency versus the reciprocal of L*, yielding a series of constant pressure curves. This pressure effect was eliminated by using dimensionless variables, allowing all of the data for a given propellant to be correlated along the same line. A one-dimensional model is proposed that considers sinusoidal perturbations, allowing for growth of the disturbance. The pressure, the burning rate, the distributed temperature in the propellent, and the energy flux from the burning gases are the quantities perturbed. (Author)