LAMINAR LIFTED FLAME AEROSOL BURNER - A TOOL FOR STUDYING AEROSOL COMBUSTION PROCESSES

摘要

The mechanisms of aerosol combustion are not well understood, mostly because of the lack of fundamental experimental information on similarities and differences between combustion of single fuel particles and clouds or aerosol jets. The experimental challenge is to produce an optically thin, laminar aerosol flame for which details of the flame structure and individual particle combustion parameters can be explored. Earlier approaches using a fluidized bed to feed particles into the flame always introduced initial turbulence and gas flow instabilities that complicated the results interpretation. In a new apparatus described in this paper, metal aerosol is produced using an electrostatic recharging of particles in the field of a flat capacitor. The powder is aerosolized within the capacitor without using any gas flows and only a small velocity, laminar gas jet is used to carry the aerosol out of the chamber through a small hole in the top capacitor plate. The aerosol number density is controlled by an electric field, independently of the gas flow rate. Preliminary results characterizing laminar, premixed, lifted aluminum-air flames are reported. The flame propagation velocities were measured, overall flame dimensions and radiation profiles were determined. Individual particle flame zones were visualized.