Effects of CO addition on laminar flame characteristics and chemical reactions of H2 and CH4 in oxy-fuel (O2/CO2) atmosphere

摘要: Abstract An experimental study is conducted to investigate the effect of CO addition on laminar flame characteristics H2 and CH4 flames in a constant-volume combustion system. In addition, one-dimensional premixed propagation processes at same conditions are simulated with update mechanisms. Results show that all mechanisms could well predict speeds CH4/CO/O2/CO2 mixtures, when ZCO large. For mixtures lower CO, always smaller than calculated ones Han mechanism. larger or ZCO2, GRI 3.0, San diego USC 2.0 overvalue undervalue speeds. When ratio CH4/CO blended fuels increases, speed firstly increases then decreases for mixtures. H2/CO/O2/CO2 diego, Davis Li H2/CO/CO2/CO2 Existing models not nonlinear trend speeds, due complex chemical effects H2/CO flames. Then, detailed thermal, kinetic diffusive discussed. Kinetic sensitivity coefficient far thermal this indicates influences mainly by effect. Based this, radical pool analysis elementary reaction R38H + O2 ↔ O + OH R99 OH + CO H + CO2 most important branching reactions positive coefficients relative low. As content fuel, oxidation plays more role. 0.9, importance O + OH. The dominates process negative R29 CO + OH CO2 + H R13H + O2(+M) HO2(+M) respectively. increasing decreasing mixture. Chemical shows be divided into two stages critical mole fraction 0.9.