Measurements of Combustion Response Function of Solid Propellants by Transient L Burners

Measurements of combustion response function of a non-metalized composite solid propellant have been carried out using two different type transient L* burners at comparatively low pressure condition. A rubber ball has been utilized to change the nozzle throat area abruptly in a pulse-like manner or in a step-like manner. Experimental data on induced transient pressure have been processed to obtain the combustion response function by either the direct Fourier transform method or curve fitting method based on quasi-steady combustion model. The transient L* burner results agree rather well with those obtained by the modulated L* burner tests in the low frequency range below 100Hz. Furthermore if standard three parameter expression of response function is adopted, the curve fitting method works well in broader frequency range.