A NUMERICAL INVESTIGATION OF TURBULENT PREMIXED METHANE-AIR COMBUSTION IN A CYLINDRICAL CHAMBER

Abstract

Turbulent premixed methane-air combustion in an axisymmetric cylindrical chamber is numerically simulated by a second-order finite volume method. Combustion chemistry is modeled by a reduced mechanism consists of 16 species and 31 elementary reactions, which includes some C1 and C2-chain species. Reaction rates are considered as minimum rates between Arrhenius rates and eddy break-up rates. Turbulent modeling is done via standard k-ε model with modified coefficients in flame cases and empirical inlet boundary conditions. All the numerical results were compared with experimental data for 3 turbulent premixed methane-air flames. Since combustion is occurred in distributed reaction zone, the turbulent intensities play an important role in prediction of the flame characteristics such as temperature and species mass fractions, specially when the flame occurs near the broken reaction zone. The results show the important role of C2-chain species in prediction of turbulent premixed flames behavior, especially in CO and O₂ mass fractions and the temperature field.

Keywords:

• Finite volume
• Methane
• Premixed
• Turbulent

Notes

constant parameters: C _μ = 0.09, C _ε1 = 1.44, C _ε2 = 1.92 (1.8 for flame cases)

[M′] = 6.5[CH₄] + 6.5[H₂O] + 1.5[CO₂] + 0.75[CO] + 0.4[O₂] + 0.4[N₂] + 1.0[Other].