Numerical Simulation of Combustion Induced Noise Using LES and Computational Aeroacoustics

Many technical combustion devices are susceptible to thermoacoustic instabilities. In this work, the noise emission by a turbulent jet flame is analyzed by means of a hybrid LES/CAA (Large Eddy Simulation/Computational Aero Acoustics) approach as a first step towards a numerical investigation of combustion instability. The hybrid LES/CAA approach is based on a LES of the reactive flow utilizing a low Mach number formulation. Within the CAA part of the simulations, linearized Euler equations (LEE) are solved. A simplified formulation to describe the thermoacoustic sound sources is extracted from the reactive LES. For the present study, the CFD code FASTEST is coupled with the aeroacoustic simulation tool PIANO. The two solvers are combined to a single tool for the description of the acoustics of reacting flows. Both codes make use of geometry flexible grids enabling the simulation of complex geometries commonly used within technical combustion systems.Copyright © 2010 by ASME