Effect of compressor unsteady wakes on a gas turbine combustor flow

Conference paper (2022)

Authors

Alessandro Soli Loughborough University
Richard Adoua Rolls-Royce plc
I. Langella Flight Performance and Propulsion - Aerospace Engineering
Paul Denman Loughborough University
Andrew Garmory Loughborough University
Gary J. Page Loughborough University
Research Group
Flight Performance and Propulsion (Aerospace Engineering) (TU Delft)
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Published Date

2022

Language

English

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Faculty

Aerospace Engineering

Department

Flow Physics and Technology

Research Group

Flight Performance and Propulsion

Abstract

In gas turbines, combustor inlets are characterised by significant levels of unsteady circumferential distortion due to compressor wakes and secondary flows, together with additional radial non-uniformity induced by the adverse pressure gradients in the pre-diffuser. This can cause non-uniform velocity distributions across the fuel injector, although the exact interaction mechanism, and the effects it has on the downstream air-fuel mixing, is not fully understood. This paper investigates the flow in an a single sector of a fully featured isothermal rig comprising of compression and combustion systems, exploiting the synchronous coupling of a compressible unsteady RANS simulation with a low-Mach LES. Validation against five-hole probe measurements shows that the coupled approach can correctly predict distortion onset and development, with no solution discontinuity at the coupling interface, and is able to preserve unsteady information. The coupled prediction is then compared against a standalone combustor simulation carried out using a circumferentially uniform inlet profile, showing that the additional turbulence from the wakes interacts with the injector, reducing the coherence of the precessing vortex core and potentially affecting the air-fuel mixing characteristics.