Abstract: A new eigenvalue analysis-based method is presented for the construction of skeletal reduced mechanisms from complex chemical reaction mechanisms. A reduced mechanism of 21 species and 83 elementary reactions for methane-air combustion was generated from detailed mechanism GRI1.2. The ignition delay time, obtained for different values of equivalence ratio, initial temperature and pressure on the basis of this reduced mechanism, were compared with those based on the detailed mechanism GRI1.2, and another skeletal mechanism DRM19. The reduced mechanism agreed favorably with the detailed model, and performed more accurately than DRM19. Two reduced mechanisms, the first involving 120 reactions among 26 species, the second, 140 reactions among 30 species, were also generated from GRI3.0. They were tested by means of premixed laminar flame calculations. The method very accurately predicted speed of flame propagation and key species concentration and even NO concentration distribution in methane combustion.

Key words: Chemical mechanism reduce, Skeletal mechanism, Eigenvalue analysis, Methane, Ignition delay time, Flame propagation speed