An experimental study of interacting swirl flows in a model gas turbine combustor

Vishwanath, RB and Tilak, PM and Chaudhuri, S (2018) An experimental study of interacting swirl flows in a model gas turbine combustor. In: Experiments in Fluids, 59 (3).

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Abstract

In this experimental work, we analyze the flow structures emerging from the mutual interaction between adjacent swirling flows at variable degrees of swirl, issued into a semi-confined chamber, as it could happen in a three cup sector of an annular premixed combustor of a modern gas turbine engine. Stereoscopic particle image velocimetry (sPIV) is used to characterize both the non-reacting and reacting flow fields in the central diametrical (vertical) plane of the swirlers and the corresponding transverse (horizontal) planes at different heights above the swirlers. A central swirling flow with a fixed swirl vane angle is allowed to interact with its neighboring flows of varied swirl levels, with constant inlet bulk flow velocity through the central port. It is found that the presence of straight jets with zero swirl or co-rotating swirling jets with increasing swirl on both sides of the central swirling jet, significantly alters its structures. As such, an increase in the amount of swirl in the neighboring flows increases the recirculation levels in central swirling flow leading to a bubble-type vortex breakdown, not formed otherwise. It is shown with the aid of Helmholtz decomposition that the transition from conical to bubble-type breakdown is captured well by the radial momentum induced by the azimuthal vorticity. Simultaneous sPIV and OH-planar laser-induced fluorescence (PLIF) are employed to identify the influence of the neighboring jets on the reacting vortex breakdown states. Significant changes in the vortex breakdown size and structure are observed due to variation in swirl levels of the neighboring jets alongside reaction and concomitant flow dilatation.

Item Type:	Journal Article
Publication:	Experiments in Fluids
Publisher:	Springer Verlag
Additional Information:	The copyright for this article belongs to the Springer Verlag.
Keywords:	Combustors; Flow fields; Flow velocity; Gas turbines; Stereo image processing; Swirling flow; Velocity measurement, Azimuthal vorticity; Different heights; Gas turbine combustor; Helmholtz decomposition; Mutual interaction; Oh planar laser induced fluorescences; Reacting flow field; Stereoscopic particle image velocimetry, Vortex flow
Department/Centre:	Division of Mechanical Sciences > Aerospace Engineering(Formerly Aeronautical Engineering)
Date Deposited:	10 Aug 2022 04:50
Last Modified:	10 Aug 2022 04:50
URI:	https://eprints.iisc.ac.in/id/eprint/75642

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