Effects of $\mathrm{H}_2$ addition and $\mathrm{CO}_2$ dilution on the methane–air diffusion flame in a coflow burner

The present paper describes the effects of hydrogen addition and carbon dioxide dilution in the natural gas on the velocity profiles and on the turbulent quantities (integral scale and Kolmogorov scale) in a cylindrical burner. The hydrogen content in the fuel is varied from $0$ to $20\%$ in volume, and the volume of carbon dioxide is varied between $0$ and $50\%$. The velocity fields and the root mean square value of velocity are determined by the particle image velocimetry technique in the reacting flow. The concentrations of $\mathrm{CO}$ and $\mathrm{NO}_x$ are found using the corresponding analyzers. The turbulent quantities are determined by a numerical method. The results show that the absence of hydrogen and the carbon dioxide content greater than $20\%$ lead to flame blow-out. Therefore, the flame is hooked to the burner if hydrogen is added. In this study, with hydrogen addition, the difference in the maximum velocity $(U_{\mathrm{max}}/U_0)$ along the bio-hythane jet is less important far from the burner due to the low density and high molecular diffusivity of hydrogen. The studies of the root mean square values of two velocity components ($U'_x$ and $U'_z$) indicate that turbulence is more important for the $U'_z$ component.