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Flame and spray dynamics during the light-round process in an annular system equipped with multiple swirl spray injectors

Prieur, Kevin and Vignat, Guillaume and Durox, Daniel and Schuller, Thierry and Candel, Sébastien Flame and spray dynamics during the light-round process in an annular system equipped with multiple swirl spray injectors. (2019) Journal Of Engineering For Gas Turbines And Power, 141 (6). 061007. ISSN 0742-4795

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Official URL: https://doi.org/10.1115/1.4042024

Abstract

A successful ignition in an annular multi-injector combustor follows a sequence of steps. The first injector is ignited; two arch-shaped flame branches nearly perpendicular to the combustor backplane form; they propagate, igniting each injection unit; they merge. In this paper, characterization of the propagation phase is performed in an annular combus- tor with spray flames fed with liquid n-hepane. The velocity and the direction of the arch- like flame branch are investigated. Near the backplane, the flame is moving in a purely azi- muthal direction. Higher up in the chamber, it is also moving in the axial direction due to the volumetric expansion of the burnt gases. Time-resolved particle image velocimetry (PIV) measurements are used to investigate the evaporating fuel droplets dynamics. A new result is that, during the light-round, the incoming flame front pushes the fuel droplets in the azimuthal direction well before its leading point. This leads to a decrease in the local droplet concentration and local mixture composition over not yet lit injectors. For the first time, the behavior of an individual injector ignited by the passing flame front is examined. The swirling flame structure formed by each injection unit evolves in time. From the igni- tion of an individual injector to the stabilization of its flame in its final shape, approxi- mately 50ms elapse. After the passage of the traveling flame, the newly ignited flame flashbacks into the injector during a few milliseconds, for example, 5 ms for the conditions that are tested. This could be detrimental to the service life of the unit. Then, the flame exits from the injection unit, and its external branch detaches under the action of cooled burnt gases in the outer recirculation zone (ORZ)

Item Type:Article
HAL Id:hal-02002022
Audience (journal):International peer-reviewed journal
Uncontrolled Keywords:
Institution:French research institutions > Centre National de la Recherche Scientifique - CNRS (FRANCE)
Université de Toulouse > Institut National Polytechnique de Toulouse - Toulouse INP (FRANCE)
Other partners > Université Paris-Saclay (FRANCE)
Université de Toulouse > Université Toulouse III - Paul Sabatier - UT3 (FRANCE)
Other partners > CentraleSupélec (FRANCE)
Other partners > SAFRAN (FRANCE)
Laboratory name:
Funders:
Safran Tech, CNRS and ANR
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Deposited On:16 Jan 2019 10:39

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