Investigation On Oxy-fuel Combustion Of Methane In A Rapidly Mixed Type Tubular Flame Burner

With increasing consumption of hydrocarbon fuels,combustion emissions has been recognized as severe sources that cause environmental problem,such as the carbon dioxide known as the main reason for global warming,and the nitrogen oxide that causes fog and haze.Thus,energy saving and low emissions have become significant topics for hydrocarbon combustion.Owing to the high burning efficiency and temperature with low pollution emissions and energy consumption level,oxy-fuel combustion can efficiently relieve the tense status of energy source shortage as well as environmental destruction.Oxy-fuel combustion of methane was investigated by using an inherently safe technique of rapidly mixed tubular flame burner,in which the fuel and the oxidizer were individually injected from four tangential slits.The influences of carbon dioxide assignment,flow rate,the burner inlet width and swirl number on the flame structure were addressed.The influences of inlet width and diameters of burners on the flammable range were also conducted.At the same time,the corresponding numerical simulations have been carried out.The results illustrate that simulation results are consistent with the experimental results verifying the reliability of the numerical simulation.The results illustrate that by assigning CO₂ to both the oxidizer slit and the fuel slit so as to maintain the oxidizer/fuel injection velocity ratio near unity,the flame structure became more uniform.The mixing rate was intensified with increasing the flow rates of fuel and oxidizer.With reducing the inlet width of the injection slit,the mixing was intensified,and in addition,the diffusion flame can be prohibited under the ultrahigh oxygen mole fraction condition.And hence the stoichiometric combustion under pure oxygen condition has achieved.The flammable range in equivalence ratio expanded with an increasing of oxygen mole fraction,and the inlet width merely affected the flammable range.The burner with larger diameter has a higher rich limit.