Influence of inlet acoustic boundary condition on large amplitude combustion instabilities : design of a robust impedance control system
type: Dataset
description: Combustion instabilities induced by a resonant flame-acoustic coupling are commonly observed in most applications of combustion from gas turbines to domestic or industrial boilers. These oscillations are detrimental by nature, and are still very difficult to predict at the design stage of a combustor. They imply numerous physical phenomena at multiple scales. They mainly result from a resonant coupling between the unsteady combustion and the acoustics of the system. The basic driving and coupling mechanisms have been extensively studied: acoustics in complex geometries and combustion dynamics of turbulent swirled flames are now reasonably well understood. However the effects of the acoustic boundary conditions on the system stability are less well documented, as they are not easy to access or to control in practical systems. They are however of prime importance as they determine the acoustic fluxes at the inlets and outlets of the combustor, as well as the preferential eigenfrequencies of the system. The main objective of this study is to investigate experimentally the influence of the inlet boundary condition of a generic turbulent burner on the observed self-sustained thermoacoustic oscillations. To carry out this investigation, a passive control solution has been developed. An innovative use of perforated panels with bias flow backed by tunable cavities allows to control the acoustic impedance at the inlet of a lean swirled-stabilized staged combustor (CTRL-Z facility). This impedance control system (ICS) has been initially designed and tested in a high load impedance tube. This facility also allowed to develop a robust impedance measurement technique, along with experimental protocols to measure acoustic velocities and fluxes. The acoustic response of perforates in both linear and nonlinear regimes was investigated as function of the plate porosity, bias flow velocity, back-cavity depth and incident pressure wave amplitude and frequency. The transition between t…
identifier: NNT: 2009ECAP0013
issued: 2026-05-25T13:08:26.863655
language: en
modified: 2026-05-25T13:08:26.863670
contact point: Organization
  fn: CCSD
keyword: acoustique
keyword: combustion
keyword: controle-passif
keyword: infoeu-reposemanticsdoctoralthesis
keyword: instabilites-thermoacoustiques
keyword: passive-control
keyword: plaques-perforees
keyword: spiotherengineering-sciences-physicsother
keyword: thermo-acoustic-instabilities
keyword: theses
landing page: https://theses.hal.science/tel-00677071

Influence of inlet acoustic boundary condition on large amplitude combustion instabilities : design of a robust impedance control system
type: Distribution
format: HTML
issued: 2026-05-25T13:08:26.895544
modified: 2026-05-25T13:08:26.817261
access URL: https://theses.hal.science/tel-00677071

test_moissonnage_selune
type: Agent