Spectroscopic Investigation of the Multiphase Diffusion Flame of an Aluminium Particle Laden Hydrogen Jet in a Hot Air Environment

Abstract

The general topology and structure of the multiphase diffusion flame of aluminum particles embedded in a hydrogen jet have been investigated experimentally within a hot air environment under ramjet relevant conditions concerning the air inlet temperature. An experimental set-up with a flat flame burner (МcКenna-type), modified with an inserted central tube for particle and carrier gas feeding, has been constructed to fulfil this task. The experiments have been conducted under ambient pressure conditions. The flame spectra distribution has been investigated with a grating spectrometer. Flame structure visualization has been conducted with two digital high-speed cameras for visible and ultra-violet ranges through interference filters and partly also an optical beam splitter plate simultaneously. This set-up has allowed to subtract background and thermal flame emissions from emissions of the aluminum burning zone. The dependence of the thermal and AlO emission distributions in VIS upon hydrogen and aluminium particle flow rates as well as the particle size is presented.