Construction and verification of reduction methane/air mechanism based on sensitivity analysis and direct relationship diagram method

The direct relationship graph (DRG) and sensitivity analysis were used to simplify the detailed mechanism of methane combustion in GRI-Mech 3.0, and finally a reduction mechanism containing 26 components and 64 elementary reactions was obtained. To verify the rationality and reliability of the reduction mechanism, the closed homogeneous reactor was used to verify that the deviation between the ignition delay time predicted by the reduction mechanism and the detailed mechanism was less than 5 %. The simulation results of the fully stirred reactor (PSR) showed that the error of the combustion temperature calculated by the reduction mechanism did not exceed 2 %, and the peak deviation of the NO mole fraction was controlled within 8%; in the laminar premixed flame simulation, the peak error of the combustion velocity predicted by the reduction mechanism was less than 3 %. Further verification by the Sandia Flame D flame experiment showed that the maximum deviation between the temperature distribution simulated by the reduction mechanism and the experimental data was 44.7 K, while the relative errors of the mass fraction distribution of components such as CH₄, O₂, H₂O and CO₂ and the experimental values were all less than 5%. Research has shown that this reduction mechanism significantly reduces the computational complexity while ensuring that the error of key parameters is less than 5 %. It is suitable for numerical simulation of complex combustion processes and provides efficient kinetic model support for engineering combustion optimization and pollutant control.