Computation of thermo-acoustic modes in combustors
Jan-willem van Leeuwen

Site of the project:
42, Avenue Gaspard Coriolis
31057 Toulouse Cedex 01

start of the project: May 2006

In August 2006 the Interim Thesis has appeared and a presentation has been given.

The Master project has been finished in June 2007 by the completion of the Masters Thesis and a final presentation has been given. For working address etc. we refer to our alumnipage.

Summary of the master project:
Combustion oscillations are frequently encountered during the development of many combustion chambers for gas turbines. Testing burners in simplified combustions chambers is a common method to verify their stability but this is also an ambiguous approach because a given burner can be unstable in one chamber and not in the other. Predicting methods are therefore requested.

A proper framework to analyse the combustion stability is the wave equation in a reacting flow. The thermo-acoustic modes can then be computed from the Helmholtz equation, the frequency domain version of the wave equation, by solving a large nonlinear eigenproblem.

The goal of this master's research is to improve the existing method for solving the nonlinear eigenproblem. The solution of this eigenproblem is one of the most time consuming parts of the analysis. The currently used solution method is a fixed point method in which in each iteration a large quadratic eigenproblem is solved. In the graduation research another approach, based on the Jacobi-Davidson method, will be investigated for solving the nonlinear eigenproblem. This techniques combines a Newton-iteration with a subspace acceleration. The Jacobi-Davidson method will be evaluated and compared with the fixed point iteration for a number of test problems, ranging from academic to realistic.

Thermo-acoustic mode in a combustion chamber

Contact information: Kees Vuik

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