Study On Combustion Characteristics Of Biomass Gas Jet Diffusion Flame

The study of the combustion characteristics of the biomass gas jet diffusion flame helps further research on the combustion characteristics of the graduated material gas,and provides a theoretical basis for the design of biomass gas combustion equipment.The designed and constructed biomass gas combustion experimental device is composed of a combustion device,a fuel supply system,a data measurement and acquisition system.The combustion device is composed of gas burners of different apertures.The gas burner is fixed on the experimental bench and connected the fuel supply system through a fuel pipe.The fuel supply system is composed of a fuel bottle and a flow controller.The data measurement and acquisition system consists of a flame shape measurement system and a flame temperature acquisition system.The flame shape is captured and recorded by a digital camera.The flame temperature was measured and collected by data acquisition instrument,K-type thermocouple and PC computer.The experimental results of Delichatsios correlation and methane jet diffusion flame length were compared to verify the reliability of the experimental device and the accuracy of the measurement results.The biomass gas was used as the fuel,and the length characteristics of the biomass gas jet diffusion flame were experimentally and theoretically studied.The effects of fuel outlet velocity and fuel volume flow on the Reynolds number Re of the flame laminar flow region were investigated.The results show that when the nozzle diameter is d=2 mm,the laminar flow area Re of the biomass gas flame is significantly higher than the typical laminar flow interval(0~2300).The dimensionless flame length L~*of methane and biomass gas laminar flow is proportional to Re.Therefore,based on the experimental results,a new type of empirical correlation of the dimensionless laminar diffusion flame length with high prediction accuracy is obtained,and the error analysis is carried out.The error results meet the accuracy requirements of engineering design and operation.Under the full turbulent state,L~*is a constant.It is found that the axial temperature distribution of the biomass gas jet diffusion flame conforms to the basic law of the axial jet diffusion flame temperature rises first and then decreases steadily.The peak temperature of the flame increases with the increase of the flow rate.However,as the diameter of the nozzle increases,the biomass gas.The effects of flame stabilizer on the diffusion flame of biomass gas jet were studied.The flame expansion length of the biomass gas jet diffusion flame on the flame stabilizer increases with the increase of the gas flow rate,and eventually tends to a fixed value.At a large flow rate,the larger the flame stabilizer,the more the flame extension length Large is.Experiments have found that flow rate,mesh number and nozzle diameter have a significant impacts on the temperature distribution of biomass gas expansion flame.The extended flame temperature of the 40 mesh flame stabilizer is gradually reduced from the center of the expanded flame in the radial direction,while the extended flame temperature of the 100 and 400 mesh flame stabilizer rises from the center of the expanded flame first and then decreases,the peak temperature of the extended flame follows the flow rate.The flame temperature increases and eventually tends to stable.The peak temperature of the extended flame decreases as the mesh and nozzle diameter increase.The maximum peak temperature of the extended flame does not exceed 1000?,and the maximum axial peak temperature of the biomass gas jet diffusion flame has exceeded 1000?.Therefore,the flame stabilizer can reduce the peak flame temperature and achieve low NO_x emissions.