S.S. Abdurakipov, V.M. Dulin, L.M. Chikishev
Kutateladze Institute of Thermophysics, Siberian Branch of RAS,
Novosibirsk State University

Investigation of swirling flame dynamics via Particle Image Velocimetry

In this paper experimental investigation of dynamics and flow structure of swirling propane-air flames at low and high swirl numbers S = 0,4; 1,0 and Reynolds number Re = 4400 was carried out using Particle Image Velocimetry (PIV) technique with 770 Hz acquisition rate. For each swirl number three combustion regimes with stoichiometric coefficient Ф = 0,7; 1,4; 2,5 were analyzed. The spatial distributions of the average velocity and components of turbulent kinetic energy were calculated from the measured ensembles of the instantaneous velocity fields. A comprehensive approach, including methods of time series analysis: Fourier Transform (FT) and the Continuous Wavelet Transform (CWT), statistical methods Proper Orthogonal Decomposition (POD) and Dynamical Mode Decomposition (DMD), was applied to the measured ensembles of velocity fields. The results of the comprehensive analysis for non-reacting and reacting flows under the influence of low and high swirl intensities indicated that combustion substantially affects the characteristics of vortex breakdown: occurrence, intensity, position of recirculation zone, as well as the spatial structure and dynamics of dominant flow instabilities.
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