Combustion Instability Characteristics of a Model Gas Turbine Burning Coal Gas with Different Combustor Geometries

Combustion instability of a synthetic coal gas flame in a partially-premixed gas turbine combustor has been numerically studied by utilizing a lumped network code, OSCILOS. Both H-2 percentage of the coal gas consisting H-2 and CH4 and the length of the combustor were varied in this study. A companion experimental data were borrowed and used for validating the numerical results. The predicted results reasonably agree well with the afore-mentioned experimental ones. It was found that the mode of the instability shifted to the higher mode when H-2 content of the gas became larger, and that the dominant frequency of the instability was reduced as the combustor was getting longer.