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SUMMARY:MechE Colloquium: Flame and thermoacoustic dynamics in gas turbine
  combustors
DTSTART:20181023T121500
DTEND:20181023T131500
DTSTAMP:20260510T165117Z
UID:2eb21b06004e026d11bcaca4fb1c6b1df236debee8c70d580a2f1e49
CATEGORIES:Conferences - Seminars
DESCRIPTION:Prof. Nicolas Noiray\, Combustion and Acoustics for Power & Pr
 opulsion Systems Laboratory\, Department of Mechanical and Process Enginee
 ring\, ETH Zürich\nAbstract:\nReacting flow instabilities in gas turbine 
 and aeroengine combustion chambers must be understood and controlled in or
 der to ensure safe and reliable operation and to increase the systems perf
 ormances. The research presented in this talk is based on experiments (e.g
 . planar laser induced fluorescence\, particle image velocimetry\, acousti
 c piezosensors)\, large eddy simulations and low order modelling. In the f
 irst part\, the problem of transition from autoignition to flame-propagati
 on\, which has a direct impact on ignition failure and on flashback risk\,
  will be discussed. This phenomenon is highly relevant for the sequential 
 combustors in the latest generation of heavy duty gas turbines\, which ena
 ble fast balance of the intermittent production from renewable sources.\n\
 nIn the second part of the talk\, recent progress on the understanding and
  control of thermoacoustic instabilities in combustion chambers will be pr
 esented. In real systems\, it is very challenging to predict thermoacousti
 c instabilities. They must be avoided at all cost because they strongly im
 pact the lifetime of the combustor parts. Several approaches like acoustic
  networks\, linearised Euler or Navier-Stokes equations\, compressible lar
 ge eddy simulations can be used to attack the problem. In this presentatio
 n\, one focuses on low order modelling in the form of coupled delayed diff
 erential equations with stochastic forcing in order to unravel nonlinear p
 henomena like avoided-bifurcations or synchronisation of eigenmodes. The s
 tatistics of the thermoacoustic transient obtained by solving the associat
 ed Fokker-Planck equations closely match the experimental observations. It
  will also be shown that the suppression of the limit-cycles using acousti
 c dampers is best achieved when the latter are tuned to the exceptional po
 ints of the thermoacoustic system.\n\nBio:\nNicolas Noiray is Assistant Pr
 ofessor at ETH Zürich\, where he leads the laboratory of “Combustion an
 d Acoustics for Power and Propulsion Systems” since August 2014. He obta
 ined his Ph.D. from the Ecole Centrale Paris in 2007\, and subsequently jo
 ined the Combustion Department of the Gas Turbine Research Division of Al
 stom. His research at ETH focuses on the modeling and control of reacting
  and non-reacting flows in practical systems like gas turbines for power g
 eneration\, aero-engines or cryogenic rocket engines.The unifying theme of
  the experimental\, theoretical and numerical research performed by his gr
 oup 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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