Experimental and Numerical Investigations on the Interaction of Flame and Flowfield Under Combustion Oscillation in the LPP Combustor
Experimental and numerical simulations were conducted to investigate the flame-flowfield interaction in a lean premixed prevaporized(LPP)combustor under oscillating condition.Numer-ical simulation was used to study the reactive flowfield and flame structure under stable condi-tion,as well as the time series pressure fluctuation and frequency spectrum of dynamic pressure under oscillating condition.It was found that reactive flowfields,flame structures,pressure fluc-tuations and the dominant frequency measured by PIV,OH-PLIF and dynamic pressure sensor in experiment were in good agreements with LES results.Large Eddy Simulation results show that the pressure fluctuation in the LPP combustor leads to the pressure difference fluctuations of the premixer,which causes the axial velocity fluctuations and flowfield distortion at the outlet of the premixer,accompanied by the formation,development,and detachment of vortex near the shear layer.The vortex changes the flame shape and position,which leads to the periodic fluctuation of the heat release rate,and causes the periodic fluctuation of the flowfield.The periodic fluctua-tions of heat release rate and flowfield are coupled together,which makes the combustion oscillation continue.
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