A method for determining the specific acoustic admittance of the inlet and outlet ports of a combustion chamber is presented. Parameter estimation techniques of Gauss linearization and genetic algorithms are employed to recover the acoustic boundary conditions. These techniques are used with a combination of two resources: dynamic pressure measurements obtained during combustor operation, and a finite element method-based model of the combustion chamber.

Results of a theoretical analysis are presented which show that the method is capable of accomplishing its mission. An observation of particular significance is the lack of sensitivity of the pressure mode shape to relatively large changes in the acoustic boundary conditions.