Numerical simulation of natural vibrations of gas in gas turbine combustors

An economical method for numerical simulation of natural excitation of gas vibrations in low-emission combustors of gas turbine units has been developed and tested. The method is based on the use of the SAS SST $k$–$\omega$ turbulence model and the turbulent combustion model with a modified equation for a variable degree of combustion completion. To model the natural excitation of gas vibrations, a factor associated with gas pressure pulsations is introduced into the source term of this equation. Isolation of one of the modes of gas vibrations prone to natural excitation is carried out using a resonant filter operating in each cell of the computational domain. The results of the computational study obtained using the proposed method make it possible to study the influence of design measures and operating parameters of natural vibrations and to approach more rationally the choice of measures to suppress them.