Audible and Ultrasonic Acoustic Emissions from Composite Solid Propellants.
Abstract
The audible and ultrasonic acoustic emissions from deflagrating composite solid propellants were monitored and analyzed to evaluate their potential use as diagnostics of the combustion and as a means for the study of fundamental burning processes. A family of composite HTPB-AP propellants were tested which include a range of AP particle sizes, aluminized and nonaluminized formulations, the effect of the addition of a catalyst, and the presence of an AFCAM aluminum coating. For the audible emissions, the frequency behavior in the 0-10 kHz range can be explained by assuming the gas phase reaction time primarily controls the oscillating frequency. The combustion noise efficiency, cannot be explained by the theories put forth, so the physical makeup of the noise source is presently unknown. Analysis of the ultrasonic emission spectra indicates that there are no distinct spectral features which can be used to identify a particular propellant by its acoustic signature. The rms emission levels, however, can be used as a reliable, nonintrusive means for detecting flaws in the propellant, identifying bad burns, and measuring burn rates. The overall level increases with increasing burn rate and chamber pressure and decreasing particle size. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 1977
- Accession Number
- ADA049517
Entities
People
- James I. Craig
- Warren C. Strahle
- William A. Bell
Organizations
- Georgia Tech