Tube Furnace Experimental And Simulation Research On Gas Combustion Characteristics

Tube furnace,whose combustion and pollutant emission control technology have always been the studied focus by research scholars at home and abroad,is widely used.The effects of nozzle diameter,gas flow rate and different equivalence ratio on the combustion characteristics of gas were experimentally studied based on the investigation of its combustion and pollutant emission technology,gas combustion and flame stability.The experiments were adopted to verify the effectiveness of Numerical calculation combustion Model,and the combustion and emission characteristics of the tube furnace were studied by numerical simulation.In order to study the effect of different equivalent ratios on the combustion characteristics of propane gas,a closed space propane gas combustion experiment platform was designed and constructed.By using both the relationship between the dimensionless flame height and the heat release rate of dimensionless flame source and Delichatsios correlation,the reliability of the fuel supply system was verified.By conducting the experiments and analyzing the experimental data,it was confirmed that the closed space only affected the equivalence ratio,which ensured the validity of the experimental setup.The correlations of dimensionless flame length and flame lifted height under the common influence of nozzle diameter,gas flow rate and equivalence ratio were obtained by analyzing the experimental data of propane gas combustion.When both nozzle diameter and fuel flow rate increased,the dimensionless flame length increased slowly as the equivalence ratio increased,but the flame lifted height increases faster and faster as the equivalence ratio increases.Numerical simulations under different combustion conditions of propane gas were carried out.The simulated and experimental flue gas temperature and NO concentration were compared.The average deviation of flue gas temperature was close to ±6.3%,and the maximum deviation was less than ±9.4%.The maximum deviation of NO concentration was less than ± 6%.Therefore,the validation of the established turbulence models,combustion models,radiation models,and NO models were checked.Numerical simulations were performed on the temperature distribution,axial velocity distribution and NO distribution and emission of the tube furnace with the excess air ratio ? of 1.05,1.10,1.15,1.20,1.25 and 1.30,respectively.The simulation results showed that,when ? was 1.10,the temperature distribution inside the furnace was uniform,and the local NO density inside the furnace was avoided to be too high.Simultaneously,the uniform heating of the tube wall could be guaranteed,and the entrainment effect caused by the higher axial velocity of the burner was obvious,which could promote the full combustion of the fuel and the flame heat radiation to the surrounding wall and also could reduce the NO emissions effectively.Furthermore,the temperature distribution,the water vaper emission and NO distribution and emission of the tube furnace were investigated when the water vapor volume fraction added into the oxidant was 0,0.03,0.05,0.08,0.10 and 0.15,respectively.The simulation results showed that,when the volume fraction of water vapor added into the oxidant was 0.10,the temperature distribution inside the furnace uniform and the NO production in the furnace area was low,which prevented the NO density inside the furnace from being excessively high effectively reduced the NO emissions.Meanwhile,the water vapor emission was low,which reduced the heat loss caused by water vapor emission.