Non-contact acoustic method for determining the combustor pressure in a model solid rocket motor

This paper presents a technique for non-contact diagnostics of on solid rocket motors (SRM) based on the analysis of acoustic vibrations generated by the supersonic jet of products combustion discharged from the nozzle. The combustor pressure in a model rocket motor fueled by E-5-0 solid propellant was determined experimentally by a non-invasive control method using a dynamic microphone located at a predetermined distance from the object of study and recording acoustic fields generated by the running engine. Experiments confirmed the possibility of non-contact determination of combustor pressure from the frequency of acoustic vibrations and the sound pressure generated by the jet of combustion products of the model SRM. Calculated pressures are in satisfactory agreement with the values recorded by intra-chamber pressure sensor.