Effect of H-2/CO ratio and N-2/CO2 dilution rate on laminar burning velocity of syngas investigated by direct measurement and simulation

• Laminar burning velocities of syngas/air premixed flames, varying with H-2/CO ratio (from 5/95 to 75/25) and N-2 or CO2 dilution rate (from 0% to 60%), were accurately measured using a Teflon coated Heat Flux burner and OH-PLIF based Bunsen flame method. Experiments were carried out at atmospheric pressure and room temperature, with fuel/air equivalence ratios ranging from fuel-lean to fuel-rich. Coupled with experimental data, three chemical kinetic mechanisms, namely GRI-Mech 3.0, USC Mech II and Davis H-2-CO mechanism, were validated. All of them can provide good prediction for the laminar burning velocity. The laminar burning velocity variations with H-2 and dilution gas contents were systematically investigated. For given dilution gas fraction, the laminar burning velocity reduction rate was enhanced as H-2/CO ratio increasing. Effects of the syngas components and equivalence ratio variation on the concentrations of radical H and OH were also studied. It appears that there is a strong linear correlation between the laminar burning velocity and the maximum concentration of the H radical in the reaction zone for syngas. This characteristic is exclusively different from that in methane air premixed flame. These findings indicated that the high thermal diffusivity of the H radical played an important role in the laminar burning velocity enhancement and affected the laminar burning velocity reduction rate under dilution condition. (C) 2014 Elsevier Ltd. All rights reserved.

Ämnesord

NATURVETENSKAP  -- Fysik -- Atom- och molekylfysik och optik (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences -- Atom and Molecular Physics and Optics (hsv//eng)

TEKNIK OCH TEKNOLOGIER  -- Maskinteknik -- Energiteknik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Mechanical Engineering -- Energy Engineering (hsv//eng)

Nyckelord

Laminar burning velocity

Heat flux method

OH-PLIF

H radical

concentration

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