Parametric Simulation of Turbulent Reacting Flow and Emissions in a Lean Premixed Reverse Flow Type Gas Turbine Combustor

Abstract

This paper describes simulation of a small stationary gas turbine combustor of a reverse flow, semi-silo type for power generation. The premixed coherent flame model (PCFM) is applied for partially premixed methane/air with an imposed downstream flame area density (FAD) to avoid flashback and incomplete combustion. Physical models are validated against the measurements of outlet temperature, product gas composition, and NO emission at the low operating pressure. Parametric study is performed to investigate the effect of load and pilot/total (P/T) fuel ratio on mixing characteristics and the resulting temperature distribution and pollutant emissions. As the P/T fuel ratio increases, the high temperature region over 1900 K enhances reaction of the mixture from the main nozzle in the primary mixing zone. For low P/T ratios, the pilot stream dilutes the mixture, on the contrary, to suppress reaction with an increasing height of the lifted flame. The NO is associated with the unmixedness as well as the mean temperature level and tends to increase with increasing load and P/T ratio. The high operating pressure does not affect overall velocity and temperature distribution, while it tends to increase NO and liner temperature under the given boundary conditions.