Experimental and theoretical study on delay time of pressurization in a pulsed solid rocket motor

The delay time in the process of reaching an equilibrium pressure in a small pulsed solid rocket motor was studied both experimentally and theoretically. It is found that the delay time takes a big portion in action time of the pulsed motor, and it increases as pressure increases. Theoretical result exhibits the same trend, while it is shorter than experimental data owing to neglecting the effect of free volume produced in the process of pressurization. The way to shorten the delay time is increasing the break-cover pressure or decreasing the initial free volume, which was investigated theoretically, and a reasonable result was obtained for designing such a motor. Also, the rule of releasing impulse in the process of pressurization was discussed. Results indicate that with the increase of equilibrium pressure, the pressure impulse as well as the proportion in total impulse increases, and the equivalent impulse point moves rightward from the center of action time.