Study On The Chemical Reaction Mechanism And In-cylinder Combustion Simulation Of Biogas

With the increasing of global energy crisis and environmental pollution,more and more people take more attention to the biogas because of its clean and renewable characteristics.In recent years,biomass gas engine use for power generation is becoming a hot topic.But there are not many research about biogas engine both at home and abroad.This thesis uses the numerical calculation to analyze the unique combustion characteristics of biogas engine because of situation.Therefore,this thesis firstly studies the chemical reaction mechanism of material gas,through sensitivity analysis to get a set of suitable for biomass gas combustion simulation simplified chemical reaction mechanism.Then the chemical reaction mechanism and three-dimensional computational fluid dynamics software coupling,build biomass gas engine combustion simulation pl atform,simulation of the biomass gas combustion in cylinder,the analysis of ignition advance angle,equivalent ratio,initial temperature,compression ratio,fuel components,for the influence of parameters on the engine combustion and emissions.The results show that the whole biomass gas engine combustion process is divided into obvious ignition lag period,obvious stage combustion and combustion after three stages.Biomass gas engine is the main pollutant of CO and NO,exhaust pollutant emission levels and biomass gas in engine cylinder is closely related to the overall level of temperature and pressure.Increase biomass gas engine ignition advance Angle,mixture using stoichiometric ratio,improve the initial temperature of the mixture in cylinder,increase the engine compression ratio,the increase of biomass gas CH 4,CO and H₂ measures can improve the content of flammable components such as the level of temperature and pressure in biomass gas engine cylinder,improve the performance of engine power,reduce CO emissions,but would make NO emissions increased significantly,is not conducive to clean combustion.Increase of CO 2 content of inert ingredients such as biomass gas,although can reduce the performance of engine power,increase CO emissions,but would make NO emissions decreased obviously.