Parametric study on solid rocket motor ignition transient and pressure oscillations onset

The startup represents a very critical phase during the whole operational life of solid rocket motors. This paper provides a detailed study of the effects on the ignition transient of the main design parameters of solid-propellant motors. The analysis is made with the use of a quasi-one-dimensional unsteady model of solid rocket ignition transient, extensively validated, and used in the frame of the Vega program, for ignition transient predictions, reconstructions, and analyses. Two baseline solid rocket motor configurations are selected for the parametric analysis: a big booster with a three-segment propellant grain shape, similar to Ariane 5, and a small booster/solid stage with an aft-finocyl grain shape, similar to Vega solid rocket motors. The discussion of the results is particularly addressed on the possible onset of the pressure oscillations during the startup of the two solid rocket motor configurations, pointing out the design parameters that affect them in terms of occurrence and amplitude.