희박 예혼합 가스터빈 연소기 3차원 전산 해석 및 검증 연구

Abstract

This paper presents 3-D simulation results by STAR-CCM+ against measurements for lean premixed combustion in a stationary gas turbine with separated pilot and main nozzles. The constant in flame area density transport equation source term was modified considering low equivalence ratio and validated comparing with experiment. The PCFM involves propagation of a laminar premixed flame with the predicted flame surface density and the equilibrium assumption in the burned gas with spatial inhomogeneities. The cooling conditions by radiation and convection are considered to calculate proper values of heat flux condition. The value of heat flux was adjusted to match the exit temperature for experiment. Parametric study is performed with respect to the ratio of pilot and total fuel. Results showed reasonable agreement with measured temperatures and consistent trends of variation with respect to the operating conditions in the tested ranges. The observed flame shape corresponds to the light emission from the diffusion flame out of the main nozzle. The predicted CO is based on the thermodynamic equilibrium assumption which led to a much higher level than measurements.