Acoustic Absorption Coefficients of the Combustion Products of Aluminized Propellants
Abstract
A resonance tube method has been used to measure the absorption of sound passed through a column of propellant gases and solid particles produced by the burning of small samples of aluminized propellant. Aluminum composition was varied to observe the effect of the increased quantity of alumina particles on sound absorption. The acoustical absorption coefficient increased with increasing aluminum concentration in the propellant. The absorption coefficient increased linearly with the frequency, consistent with the particulate damping theory of Epstein and Carhart. This theory was also used to estimate the sizes of alumina particles produced in the experiment. By a process of curve fitting, the inferred particle radii were either 0.80 or 3.5 microns, two solutions were possible. The initial average radius of the aluminum was 2.3 microns. Despite the fact that a statistical distribution of particle size was not considered in curve-fitting the data, the reasonableness of the calculated particle size lend further support to the Epstein and Carhart theory.
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 01, 1965
- Accession Number
- AD0461332
Entities
People
- A. Ribnick
- H. F. Calcote