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SUMMARY:IGM Colloquium: Flame and thermoacoustic dynamics in gas turbine c
 ombustors
DTSTART:20181023T121500
DTEND:20181023T131500
DTSTAMP:20260609T210824Z
UID:7c35b9d6f7f8cc940e0d9ed3dda8d222ceb070b0933cb0e2987bc146
CATEGORIES:Conferences - Seminars
DESCRIPTION:Prof. Nicolas Noiray\, ETH Zürich\, Combustion and Acoustics 
 for Power and Propulsion Systems\nReacting flow instabilities in gas turbi
 ne and aeroengine combustion chambers must be understood and controlled in
  order to ensure safe and reliable operation and to increase the systems p
 erformances. The research presented in this talk is based on experiments (
 e.g. planar laser induced fluorescence\, particle image velocimetry\, acou
 stic piezosensors)\, large eddy simulations and low order modelling. In th
 e first part\, the problem of transition from autoignition to flame-propag
 ation\, which has a direct impact on ignition failure and on flashback ris
 k\, will be discussed. This phenomenon is highly relevant for the sequenti
 al combustors in the latest generation of heavy duty gas turbines\, which 
 enable fast balance of the intermittent production from renewable sources.
 \nIn the second part of the talk\, recent progress on the understanding an
 d control of thermoacoustic instabilities in combustion chambers will be p
 resented. In real systems\, it is very challenging to predict thermoacoust
 ic instabilities. They must be avoided at all cost because they strongly i
 mpact the lifetime of the combustor parts. Several approaches like acousti
 c networks\, linearised Euler or Navier-Stokes equations\, compressible la
 rge eddy simulations can be used to attack the problem. In this presentati
 on\, one focuses on low order modelling in the form of coupled delayed dif
 ferential equations with stochastic forcing in order to unravel nonlinear 
 phenomena like avoided-bifurcations or synchronisation of eigenmodes. The 
 statistics of the thermoacoustic transient obtained by solving the associa
 ted Fokker-Planck equations closely match the experimental observations. I
 t will also be shown that the suppression of the limit-cycles using acoust
 ic dampers is best achieved when the latter are tuned to the exceptional p
 oints of the thermoacoustic system.\n\nBio:\nNicolas Noiray is Assistant P
 rofessor at ETH Zürich\, where he leads the laboratory of “Combustion a
 nd Acoustics for Power and Propulsion Systems” since August 2014. He obt
 ained his Ph.D. from the Ecole Centrale Paris in 2007\, and subsequently j
 oined the Combustion Department of the Gas Turbine Research Division of A
 lstom. His research at ETH focuses on the modeling and control of reactin
 g and non-reacting flows in practical systems like gas turbines for power 
 generation\, aero-engines or cryogenic rocket engines.The unifying theme o
 f the experimental\, theoretical and numerical research performed by his g
 roup is the study of flow instabilities at various time and length scales.
LOCATION:MED 0 1418 https://plan.epfl.ch/?room==MED%200%201418
STATUS:CONFIRMED
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