LES and acoustic analysis of thermo-acoustic instabilities in a partially premixed model combustor

Ignacio Hernández (1) , Gabriel Staffelbach (1) , Thierry Poinsot (2) , Juan C. Román Casado (3) , Jim B.W. Kok (3)

1 CERFACS - Centre Européen de Recherche et de Formation Avancée en Calcul Scientifique
2 IMFT - Institut de mécanique des fluides de Toulouse
3 Laboratory of thermal engineering (Twente, Netherlands)

Numerical simulations were performed using Large Eddy Simulation (LES) and acoustic analysis tools to study thermo-acoustic instabilities in an academic burner. The configuration studied corresponds to a methane/air burner installed at the University of Twente (The Netherlands). It operates under fuel-lean partially premixed conditions at atmospheric pressure, and was built to study thermo-acoustic instabilities in conditions representative of gas turbine Lean Premixed systems: gaseous fuel is injected upstream of the combustor and has a limited time to mix with air. Even though the objective is to burn in a premixed mode, the actual regime corresponds to a partially premixed flame where strong equivalence ratio variations are created especially during combustion instabilities. Capturing these modes with LES is a challenge: here, simulations for both stable and unstable regimes are performed. In the unstable case, the limit cycle oscillations (LCO) are characterized and compared to experimental results. Reasonable agreement is found between simulations and experiments.

Mots clés: Combustion; Thermo-acoustics; Limit cycles; Large Eddy Simulation

Domaines: Mécanique des fluides [physics.class-ph]; Mécanique des fluides [physics.class-ph]

Ignacio Hernández, Gabriel Staffelbach, Thierry Poinsot, Juan C. Román Casado, Jim B.W. Kok. LES and acoustic analysis of thermo-acoustic instabilities in a partially premixed model combustor. Comptes rendus de l’Académie des sciences. Série IIb, Mécanique, 2013, vol. 341, pp.121-130. ⟨10.1016/j.crme.2012.11.003⟩. ⟨hal-00930014⟩