Instantaneous Flow Structures in a Reacting Gas Turbine Combustor

While many researchers have studied swirl-stabilized and other model gas turbine combustors, very few have investigated the flow field and combustion within a gas turbine combustor operated with realistic Jet-A fuel at elevated pressures and inlet temperatures. In this paper we present results from an investigation into the flow field and flame locations within a unique combustor furnished with an injector designed by GE Aircraft Engines. The combustor provides high optical access which has allowed the use of Particle Imaging Velocimetry to probe both instantaneous vortex and recirculation zone structures in the flow and obtain ensemble averaged profiles of pertinent turbulence quantities. Both non-reacting and reacting conditions were studied to assess the eects of a flame on the flow within the combustor. All reacting conditions were run with liquid Jet A as fuel. This too provides a more realistic configuration for it accurately captures the eects of droplet/spray combustion along with the correct heat release from a heavy hydrocarbon fuel. The location of the flame front was imaged using Planar Laser Induced Fluorescence (PLIF) of formaldehyde. This study is one of the first to apply PLIF to a gas turbine combustor running liquid Jet A. Important flow features present in the combustor have been identified and key dierences between the reacting and non-reacting flow fields have been noted. With information about both the flow and flame front, structures that have not been highlighted in the past are shown to be important in the operation of the combustor. These results have indicated that the time-averaged flow field masks some very important details of the flow within a gas turbine combustor.

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