Publication type: Article in scientific journal
Type of review: Peer review (publication)
Title: Low-order modeling of can-annular combustors
Authors: Fournier, Guillaume J. J.
Meindl, Max
Silva, Camilo F.
Ghirardo, Giulio
Bothien, Mirko
Polifke, Wolfgang
et. al: No
DOI: 10.1115/1.4051954
Published in: Journal of Engineering for Gas Turbines and Power
Volume(Issue): 143
Issue: 12
Page(s): 121004
Issue Date: 2021
Publisher / Ed. Institution: The American Society of Mechanical Engineers
ISSN: 0742-4795
1528-8919
Language: English
Subjects: Thermoacoustics; Modelling
Subject (DDC): 530: Physics
620: Engineering
Abstract: Heavy-duty land-based gas turbines are often designed with can-annular combustors, which consist of a set of identical cans, acoustically connected on the upstream side via the compressor plenum, and, downstream, with a small annular gap located at the transition with the first turbine stage. The modeling of this cross-talk area is crucial to predict the thermo-acoustic modes of the system. Thanks to the discrete rotational symmetry, Bloch wave theory can be exploited to reduce the system to a longitudinal combustor with a complex-valued equivalent outlet reflection coefficient, which models the annular gap. The present study reviews existing low-order models based purely on geometrical parameters and compares them to 2D Helmholtz simulations. We demonstrate that the modeling of the gap as a thin annulus is not suited for can-annular combustors and that the Rayleigh conductivity model only gives qualitative agreement. We then propose an extension for the equivalent reflection coefficient that accounts not only for geometrical but also flow parameters, by means of a characteristic length. The proposed model is in excellent agreement with 2D simulations and is able to correctly capture the eigenfrequencies of the system. We then perform a Design of Experiments study that allows us to explore various configurations and build correlations for the characteristic length. Finally, we discuss the validity limits of the proposed low-order modeling approach.
URI: https://digitalcollection.zhaw.ch/handle/11475/23482
Fulltext version: Published version
License (according to publishing contract): Licence according to publishing contract
Departement: School of Engineering
Organisational Unit: Institute of Energy Systems and Fluid Engineering (IEFE)
Appears in collections:Publikationen School of Engineering

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