Experimental investigation of entropy waves' evolution for understanding of indirect combustion noise in gas turbine combustors

Hosseinalipour, S.M., Fattahi, A., Khalili, H., Tootoonchian, F. and Karimi, N. (2020) Experimental investigation of entropy waves' evolution for understanding of indirect combustion noise in gas turbine combustors. Energy, 195, 116978. (doi: 10.1016/j.energy.2020.116978)

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Achieving clean and quiet combustion in gas turbines is essential for improving many low-carbon energy and propulsion technologies. This often requires suppression of combustion instabilities and combustion generated noise in gas turbine combustors. Entropy noise is the less explored mechanism of combustion generated sound. Central to the emission of entropic sound is the survival of entropy wave during convection by the mean flow and reaching the combustor exit nozzle. Yet, the annihilation of entropy waves in this process is still poorly understood. To address this issue, the evolution of convected entropy waves in a fully-developed, cold flow inside a circular duct is investigated experimentally. Entropy waves are produced by a well-controlled electrical heater. Fast-response, miniaturized thermocouples arranged over a moveable cross-section of the duct are employed to record the state of entropy waves at different axial locations along the duct. Hydrodynamic parameters including Reynolds number and turbulence intensity are varied to investigate their effects upon the wave decay. The results show that the decay process is strongly wavelength dependent. It is found that the wave components with wavelengths larger than the duct diameter are almost unaffected by the flow and therefore remain essentially one-dimensional. However, other spectral components of the wave are subject to varying degrees of dissipation and loss of spatial correlation. Overall, the results support the recent numerical findings about the likelihood of wave survival in adiabatic flows. They further clarify the validity range of the one-dimensional assumption commonly made in the literature.

Item Type:Articles
Additional Information:Nader Karimi acknowledges the partial support of EPSRC through grant number EP/N020472/1.
Glasgow Author(s) Enlighten ID:Karimi, Dr Nader
Authors: Hosseinalipour, S.M., Fattahi, A., Khalili, H., Tootoonchian, F., and Karimi, N.
College/School:College of Science and Engineering > School of Engineering > Systems Power and Energy
Journal Name:Energy
ISSN (Online):1873-6785
Published Online:20 January 2020
Copyright Holders:Copyright © 2020 Elsevier
First Published:First published in Energy 195:116978
Publisher Policy:Reproduced in accordance with the copyright policy of the publisher

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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
172394Thermally Driven Heat Pump Based on an Integrated Thermodynamic Cycle for Low Carbon Domestic Heating (Therma-Pump)Zhibin YuEngineering and Physical Sciences Research Council (EPSRC)EP/N020472/1ENG - Systems Power & Energy