Accession Number : AD0753111

Title :   Suppression of Combustion Instability in Rocket Motors Using Electrothermal Acoustics,

Corporate Author : UNITED TECHNOLOGY CENTER SUNNYVALE CALIF

Personal Author(s) : Hermsen,R. W. ; Babcock,W. R. ; Cattaneo,A. G.

Report Date : OCT 1972

Pagination or Media Count : 42

Abstract : It was previously demonstrated that a conductive flame with a suitable arrangement of electrodes and coupling circuitry can transform an electrical signal into a high level acoustic output at audible and ultrasonic frequencies. Experimental evidence also indicated that complex effects involving the optical and electromagnetic spectrum took place concurrently. The objective of this research was to obtain a fundamental understanding of the observed phenomena to allow evaluation of potential applications in the fields of combustion instability, noise suppression, ultrasonic sound generation, communications and RF effects. Data on the acoustic, optical, electrical, and microwave scattering properties of a seeded oxygen-acetylene flame were obtained over the frequency range up to 150 kHz. A theoretical model was developed which correctly predicts the frequency dependent electrical impedance of the flame and the amplitude and directivity of the external sound field. (Author)

Descriptors :   (*ROCKET ENGINE NOISE, MODULATION), (*ROCKET ENGINES, *SCREAMING COMBUSTION), FLAMES, ELECTRIC FIELDS, ACOUSTICS, ELECTROMAGNETIC FIELDS, ELECTRICAL PROPERTIES, EXPERIMENTAL DATA

Subject Categories : Acoustics
      Combustion and Ignition
      Rocket Engines

Distribution Statement : APPROVED FOR PUBLIC RELEASE