Mixing and stabilization study of a partially premixed swirling flame using laser induced fluorescence

Journal Article · Sat Jan 15 04:00:00 EST 2011 · Combustion and Flame

DOI:https://doi.org/10.1016/J.COMBUSTFLAME.2010.08.004· OSTI ID:21396168

Galley, D; Ducruix, S; Lacas, F; Veynante, D ^[1]

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1. Ecole Centrale Paris, Laboratoire EM2C, CNRS, Chatenay Malabry (France)

A laboratory-scale swirling burner, presenting many similarities with gas turbines combustors, has been studied experimentally using planar laser induced fluorescence (PLIF) on OH radical and acetone vapor in order to characterize the flame stabilization process. These diagnostics show that the stabilization point rotates in the combustion chamber and that air and fuel mixing is not complete at the end of the mixing tube. Fuel mass fraction decays exponentially along the mixing tube axis and transverse profiles show a gaussian shape. However, radial pressure gradients tend to trap the fuel in the core of the vortex that propagates axially in the mixing tube. As the mixing tube vortex enters the combustion chamber, vortex breakdown occurs through a precessing vortex core (PVC). The axially propagating vortex shows a helicoidal trajectory in the combustion chamber which trace is observed with transverse acetone PLIF. As a consequence, the stabilizing point of the flame in the combustion chamber rotates with the PVC structure. This phenomenon has been observed in the present study with a high speed camera recording spontaneous emission of the flame. The stabilization point rotation frequency tends to increase with mass flow rates. It was also shown that the coupling between the PVC and the flame stabilization occurs via mixing, explaining one possible coupling mechanism between acoustic waves in the flow and the reaction rate. This path may also be envisaged for flashback, an issue that will be more completely treated in a near future. (author)

• OSTI ID: 21396168
• Journal Information: Combustion and Flame, Journal Name: Combustion and Flame Journal Issue: 1 Vol. 158; ISSN CBFMAO; ISSN 0010-2180
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
ACETONE
AIR
BURNERS
COMBUSTION CHAMBERS
COMBUSTION KINETICS
COMBUSTORS
COUPLING
FLAMES
FLOW RATE
FUELS
GAS TURBINES
HYDROXYL RADICALS
MASS
MIXING
PRESSURE GRADIENTS
ROTATION
SHAPE
SOUND WAVES
STABILIZATION
TRAJECTORIES
TRAPS
TUBES
VAPORS
VELOCITY
VORTEX FLOW
VORTICES