Skeletal oxidation mechanism for n-Dodecane in gas turbine combustor simulations

Accurate forecasting of gas turbine combustor performance using computational fluid dynamics (CFD) requires the development of predictable skeletal mechanisms for hydrocarbon fuels. This study presents a skeletal mechanism for n-dodecane, a representative surrogate for diesel, comprising 33 species and 96 reactions. The mechanism was constructed using the decoupling methodology, improved path flux analysis with multiple generations, and the direct relationship graph for error propagation. It was validated across a temperature range of 700-1400 K, an equivalence ratio of 0.5-1.0, and pressures ranging from 0.8-4 MPa. The mechanism effectively predicts laminar flame speed, ignition delay and the trends in major species concentrations under gasturbine operating conditions. A sensitivity analysis of the laminar flame speed indicated that the reactions CO + OH = CO2 + H and H + O2 = O + OH showed positive trends. Using this skeletal mechanism, simulations of a realistic single tube in a can-annular combustor were conducted with the flamelet-generated manifold combustion model and the large-eddy simulation method. The predicted temperature distribution closely matched experimental data, demonstrating that the proposed mechanism is capable of accurately simulating combustion in the realistic gas-turbine combustor.