Syngas Turbulent Flame Measurement And Characterization By OH-PLIF

The combustion of syngas can reduce harm to the environment significantly,while the insufficiently understanding of the mechanism of syngas combustion hinder the way of using it effectively.Based on that context,a premixed turbulent Bunsen burner test rig was set up.Using planar laser induced fluorescence(OH-PLIF)technology,which has been widely used for decades in the field of combustion diagnosis,the effects of equivalence ratio,H2 content and turbulence intensity on the average OH concentration,relative fluorescence intensity,turbulent flame velocity and fluctuation of premixed turbulent flames were analyzed.Under all experimental conditions,the maximum average OH concentration and the relative fluorescence intensity of the same position rise with higher equivalence ratio,H2 content and turbulence intensity.The relative fluorescence intensity of the turbulent flame rises at first and then decreases along with the axial distance for all experimental conditions.Higher equivalence ratio leads to broader regions of OH radicals and the location of the maximum concentration of OH radicals decreases as the equivalence ratio goes up.With more H2 contained,the concentration of OH radicals jumps significantly because H2 can foster the reaction producing OH radicals.Turbulent flame velocity was obtained using the angle method from the averaged OH-PLIF images.The results show that the turbulent flame velocity is much greater than the laminar flame velocity,and turbulent flame velocity increases with the equivalence ratio,hydrogen content,and turbulence intensity.As to transient characteristics,5000 consecutive transient OH-PLIF images were analyzed.The results show that the probability distribution of the maximum relative fluorescence intensity and the height of it is Gaussian distribution.The increase of equivalence ratio,H2 fraction and turbulent can promote the fluctuation of the temperature,while making the fluctuation position smaller.