Investigation On The Ignition Delay Of Biomass Synthesis Gas At High Temperature And High Pressure Ranges

Alternative fuels and advanced combustion mode applied in internal combustion engine have been discovered due to the depletion of fossil fuels and severe environmental problem.Biomass synthesis gas(biosyngas)is a promising alternative fuel with carbon neutral feature and homogeneous charge compression ignition(HCCI),as an advanced combustion mode,is mainly controlled by the chemical kinetics of fuels.Therefore,it is crucial to investigate the chemical kinetic characteristics in order to realize ideal HCCI mode.The ignition delay of bio-syngas and blends of bio-syngas/dimethyl ether has been experimentally studied respectively at high pressure and high temperature ranges in a shock tube.The results show the effects of pressure,temperature,equivalence ratio and components on the ignition delay.Additionally,experimental results are compared to the predicted results accomplished by mechanisms showing excellent agreements.The ignition process is analyzed in terms of the chemical kinetics of the fuels,including sensitivity coefficient,reaction pathway and variation of free radicals' concentration.Sensitivity analyses show the most sensitive reactions that influence the ignition delay and the reaction pathway analyses indicate the main reaction pathway during the ignition process of the main components in fuels and the contribution rate of principal elementary reactions.Variations of free radicals' concentration and rate of production with operation conditions are vital parameters to interpret the ignition delay characteristics.