Spectroscopic measurements to determine temperature and carbon particle size in an absorbing propane diffusion flame

Abstract

Self-absorbed radiation from solid carbon particles in an axially symmetric propane diffusion flame, as well as from the sodium D line (5890 Å), was examined spectroscopically. Radial distributions of the emission and absorption coefficients were obtained by inverting lateral specific intensity data. The temperature distribution was obtained by applying Kirchoff's law to the local emission and absorption coefficients. Carbon particle temperature agrees with the sodium D line temperature over a major portion of the carbon zone. Absorption measurements of the carbon particles were made at wavelengths ranging from 2330 Å to 11,000 Å. From these measurements, the size of the carbon particles is estimated to be between 200 Å and 300 Å.