Lewis number effects on lean premixed combustion characteristics of multi-component fuel blends

Variation in natural gas composition, alongside the potential for H2 enrichment, creates significant changes to premixed flame behaviour. To strengthen fundamental understanding of lean multi-component alternative fuel blends, an outwardly propagating spherical was employed measure speeds and Markstein lengths C1C4 hydrocarbons, precisely mixed blends CH4/C2H6, CH4/C3H8 CH4/H2. Theoretical relationships between length Lewis Number are explored effective number formulations. Under conditions, equal volumetric additions C3H8 (30% vol.) CH4 resulted similar augmentation burning velocity, however, opposite susceptibility preferential diffusional instability noted. At a fixed equivalence ratio 0.65, limited composition provide marked change response with addition C2H6 CH4. For CH4/H2 mixtures, based formulation yielded favourable correlation, whilst heat-release model better agreement blends. Modelling work suggests that measured enhancement flames upon or is strongly correlated heat release rates production H radicals. Furthermore, systematic analysis speed effects (thermal, kinetic, diffusive) methane undertaken. Augmented propagation demonstrated be principally Arrhenius effect, predominantly through reduction associated activation energy. Finally, plausible short-term variations hydrogen-enriched were investigated experimentally numerically. leanest small CH4:C3H8 content at fraction discernible stretch related behaviour, reflection thermo-diffusive behaviour each fuel's response.