Measurements of the Wake Flame behind a Sphere via Raman Scattering

Abstract

An experimental study was made of the structure of the wake flame formed behind a porous sphere from which methane was discharged into a uniform stream of dust-free dry air. The laser Raman scattering technique was applied to measure the temperature and the number density of gaseous molecules in the flame. Flame temperature was determined from the measured results of the Stokes-Raman spectrum of nitrogen molecule which was irradiated by the Argon laser (488 nm). measurements were also made of the flame emission spectroscopy. The results showed that the maximum temperature was observed near the periphery of the visible flame. The ratio of the number densities of oxygen and nitrogen molecules in the central portion of the flame was much lower than the value in the room air. Strong OH emission was observed near the maximum temperature region.