Analysis of Combustor Acoustic Resonances Using an Efficient Transient Solver
To reduce combustion induced dynamic vibrations, a thorough understanding of a combustor’s acoustic characteristics at all operational conditions is imperative. Acoustic methods that rely on the solution of the wave equation are not adequate to accurately predict acoustic resonance in any real combustor with thermal gradient and velocities. Also, solutions of the 3-D transient Navier-Stokes equations are impractical, even with today’s fast computers. A method is described herein that utilizes an efficient one-dimensional transient Euler solver to determine all acoustic resonance frequencies of a combustor at a given operating condition. Area changes, viscous losses, local temperatures, and open/closed wall-boundaries are modeled with a two-equation model. The analysis method was utilized to determine the dynamic pressures of a 20 MW industrial gas turbine’s combustor. Results compared favorably to field testing results of the same gas turbine.