Measurements of CO and NOx Emissions from Premixed Turbulent Methane/Hydrogen Flames

This paper presents measurements of the sensitivity of NO and CO emissions from CH4/H2 combustion to variations in turbulence intensity. Existing studies of exhaust emissions either focus on laminar modeling and measurements, or report device level measurements from practical combustors. However, there are limited fundamental studies of emissions characteristics of turbulent systems, the focus of this study. Because of the strong stretch sensitivity of these mixtures, local temperatures/reaction rates along the turbulent front can differ markedly from mixture averaged properties, and they are very sensitive to turbulence. Single-point emissions measurements are presented for turbulent premixed H2/CH4 flames from a contoured nozzle Bunsen burner with variable turbulence. Emissions are measured at varying residence times and incoming flow turbulence intensities. Data show the clear benefit of H2 blending on CO emissions, both due to the expected reduction in C atoms, but also due to faster relaxation of flame generated CO towards equilibrium. It also shows negligible impact of turbulence intensity on NO emissions at constant CO for CH4.