Chemiluminescent emission and flow velocity field of an acoustic excited LPG diffusion flame

Resumo

The presence of an acoustic actuation can drastically change the structure of a diffusion flame produced in a cylindrical burner. This work presents a spectroscopic study of the soot and instable radicals (CH* and C2*) chemiluminescent emissions in an acoustic excited jet diffusion flame of Liquefied Petroleum Gas - LPG. Frequencies from 500 Hz to 600 Hz and sound pressures between 490 Pa and 2730 Pa were employed. Planar Image Velocimetry (PIV) experiments were carried out in order to understand the acoustic effect in the velocity field profile. Frequency of 575 Hz and 600 Hz conditions presented more effective acoustic performance, making the flame begin to show characteristics of a partially premixed flame. A reduction in the soot emission and an increase of the instable radicals were also observed. The PIV results showed a sequence of periods of expansion and compression of the fuel with the acoustic actuation, what led to an increased rate of air-fuel mixture, changing the flame structure. © 2013 Praise Worthy Prize S.r.l. - All rights reserved.

Palavras-chave