RESEARCH STUDY OF LIGHT EMISSION CAUSED BY PRESSURE FLUCTUATIONS IN ROCKET ENGINES
Abstract
Simultaneous high frequency measurements of light emission and pressure were made in an oscillating premixed methane-air, 3 inch i. d. x 16 inch long rocket engine at pressures from 50 to 150 psig. Using filtered photomultiplier tubes, emission in the OH (0,0) band (3064A), the CH (0, 0) band (4315A), and total luminosity (CO + O = CO2 + photons) over the range of the 1P28 phototube were monitored. Depending on injector arrangement, longitudinal oscillations of nominally 1150 cps and transverse oscillations of mainly 7100 cps and 14,000 cps (1st tangential and 1st radial) were encountered. With transverse oscillations, no corresponding emission fluctuations were observed, which may be owed to the aspect angle of the detectors, 90 degrees to the engine axis (0 degrees to the plane or pressure propagation). The longitudinal pressure oscillations were always accompanied by emission fluctuations of the same frequency. Emission from the chain-branching radicals OH and CH lagged the pressure by about .2 milliseconds except at 150 psig where the lag was zero. At 50 and 100 psig, the total luminosity was in phase with pressure. Visible spectra were photographically recorded, and showed similarity to previous laboratory spectra of flames as a function of pressure.
Document Details
- Document Type
- Technical Report
- Publication Date
- May 01, 1965
- Accession Number
- AD0622524
Entities
People
- B. Hornstein