SPECTROMETRY AS A DIAGNOSTIC TOOL FOR THE MONITORING OF THE INTERNAL BALLISTICS OF SOLID ROCKET MOTORS

摘要

An experimental technique that enables an internal ballistics designer to follow theprogress of the solid propellant burning surface using spectrometric technique was developed.Chemical compounds that emit radiation after exposure to the hot combustion gases (referredto as chemical tracers) were placed on the motor casing prior to the propellant castingprocess. The burn time up to the tracers exposure was calculated using an internal ballisticssimulation program. During a static firing, the SRM plume was observed using aspectrometer, and when the propellant surface regression exposed the chemical traces, theirradiation was observed and identified using a designated computer program. The timing ofthe radiation appearance defines the actual time at which the propellant surface reaches thecasing. If the observed time differs from the calculated burning time for this part of the grain,one can deduce that the propellant surface regression did not proceed as calculated. Thisinformation, together with the usual data gathered from the pressure and thrust transducers,enables an internal ballistics designer to better understand the propellant surface regressionprocess, fine-tune his predictive models and may provide the additional data needed tounderstand the possible burning irregularity – crack, debonding or other.