Characteristics of a Methane Jet Flame in Elevated Pressure and Oxy-Fuel Atmosphere Using Large Eddy Simulation with Tabulated Chemistry

The pressurized oxy-fuel combustion is a promising CO(2)capture technology for its further reduction of CO(2)capture cost. In order to study the combustion behaviors of hydrocarbons under different pressures and atmospheres, a methane/air jet flame is used as the simulation target, with modifications on its oxidizer species and operating pressure. A Large Eddy Simulation (LES) with a tabulated chemistry model is employed, whose lookup tables are constructed by using a 2-D counterflow diffusion flame under different atmosphere and pressure conditions. The original flame with detailed experimental data is used for the validation of the model accuracy, and the simulation results show good agreement with the experiments. The detailed profiles of the temperature, species, and mixture fraction are analyzed. Compared with the air-fired, the flame in the oxy atmosphere is shorter and thinner. Important species and radicals are compared. The comparison shows that under elevated pressure, the differences caused by oxy atmosphere is similar to those found under atmospheric pressure. With the elevation of pressure from 0.1 MPa to 1.5 MPa, the flame height becomes smaller while the radial width is larger near the inlet, which can be observed in both air-fired and oxy-fired conditions. Under elevated pressures, the flame temperature changes slightly, but CO production increases noticeably in the fuel-rich regions.