1 Laminar Burning Velocities of Typical Syngas Compositions

Syngas is being recognized as a viable energy source worldwide, particularly for stationary power generation due to its availability as a product of bio and fossil fuel gasification. However, there are gaps in the fundamental understand of syngas combustion characteristics, especially at elevated pressures that are relevant to practical combustors. In this work, constant volume spherical expanding flames of three typical syngas compositions resulting from wood gasification have been employed to measure the laminar burning velocity under stoichiometric conditions for pressures ranges between 1 and 20 bar. Over the ranges studied, the burning velocities are fit by the functional formula of Metghalchi and Keck. The influence of stretch rate upon the burning velocity is indicated by Markstein lengths determined at constant pressure by schlieren photography. Conclusion can be drawn that the burning velocity decreases with the increase of pressure. In opposite, an increase in temperature induces an increase of burning velocity. The higher burning velocity value is obtained for the downdraft syngas. This result is endorsed to the higher heat value, lower dilution and higher volume percentage of hydrogen in the downdraft syngas. Small Markstein lengths were obtained for the three syngas compositions, which is indicative of a small influence of flame stretch on burning velocity of syngas flames