ANALYSIS AND CONTROL METHOD OF TRANSVERSE COMBUSTION INSTABILITIES IN A MULTI-NOZZLE CAN COMBUSTOR

The requirement of cutting Nox emissions makes modern gas turbines prone to combustion instabilities. Wherein the transverse mode instabilities have received more challenges in multi-nozzle can combustor and the effective control method is still necessary in suppressing transverse oscillations. To provide a methodology to predict and control transverse combustion instabilities, a three-dimensional analytical model is presented in this work, which treats multiple nozzles and perforated plates in can combustors as equivalent distributed sources. Then a dispersion relation equation is established and the stability behaviour is presented by eigenvalues. Results show that combustion instabilities of transverse mode are sensitive to the open area ratio of perforated plates. However, the variation of aperture has little effect on the stability as well as the growth rate of azimuthal modes, while it plays a relatively important role in the stability variation of radial mode. In a word, this work provides a feasible analysis method for the prediction and control of combustion instability in a multi-nozzle can combustor.