variavel0=<b>Pedro Teixeira Lacava</b> - lacava@aer.ita.br Instituto Tecnológico de Aeronáutica
<b>Vitória Oliveira Hirth Bastos</b> - vitoriahb@zipmail.com.br INPE - LCP
<b>Marco Aurélio Ferreira</b> -  INPE - LCP
<b>João Andrade Carvalho Jr.</b> - joao@feg.unesp.br UNESP
<b>Abstract.</b> Pulsating combustion has won interest in current research due to the indications that its application in energy generation can offer several advantages, such as: fuel economy, reduced pollutants formation, increase the rate of convective heat transfer and reduced investment when compared with conventional techniques. However, pulsating combustion systems where the combustion process induces the acoustic oscillation, in general, are operationally unstable and are not very attractive for industrial applications. In this way, the future of pulsating flames will be in processes where the oscillation is induced by external means, for example by a speaker. The present work presents and discusses the effect of the amplitude and frequency in the format of free diffusion flame of LPG. A strategically positioned speaker acoustically excites the mixture before the burner exit, and a CCD camera made the flame visualization. Then, a tomographic reconstruction process was applied in the obtained images. Combustion gases concentrations were also analyzed (CO, CO2, NOx and O2). The results show that oscillations conditions can change substantially the flame structure. The presence of an acoustic field may improve the reactants mixing rate. Without oscillations the flame is laminar and has a yellow aspect. Depending the frequency and amplitude, the flame becomes turbulent and blue closed to the burner jet exit. However, due the improve of reactants mixing, NOx emissions is higher than non-pulsating condition.
<b>Keywords.</b> Pulsating Combustion, Flame Tomographic Reconstruction.