EXPERIMENTS FOR THE MEASUREMENT OF THE ACOUSTIC IMPEDANCE OF A BURNING SOLID PROPELLANT
Abstract
Progress of a program to measure the acoustic impedance of a burning solid propellant surface is described. Improved accuracy of measurements has been achieved. Data which has been obtained on passive samples with this improved accuracy has permitted a more reliable evaluation of equations which are being used for the calculation of sample impedances. This has shown that correction for the source and microphone impedances is necessary both at atmospheric and elevated pressures in order to obtain, with vented sound chambers, results of sufficient a curacy to meas re the burning propellant surface impedance. A microphone designed to withstand the rigors of active shot conditions has been adopted and applied in further studies of noise arising from the propellant combustion. It has been fo nd that the combustion noise intensity fluctuates over a considerable range. It is of sufficient magnitude, even within limited sound frequency ranges, to require corrections or means of overcoming the effect in measurements using injected sound for determination of acoustic impedance. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 21, 1962
- Accession Number
- AD0292019