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摘要
This paper presents the reactivity of different alkanes ranging from C-1 to C-4 over platinum. The four fuels used are compressed natural gas (CNG), liquefied petroleum gas (LPG), butane, and ethane. Experiments are performed to study the effects of varying the temperature of the incoming mixture (T-jet), its equivalence ratio (phi) and the Reynolds number (Re), on the reactivity limits and species distributions. Platinum surface temperatures as well as species profiles streamwise and transverse to the plate are investigated. The reactivity limits of ethane over platinum are discussed in details. For flameless combustion (defined by the the presence of reactions on the plate without a gaseous flame), it is found that the plate temperatures of ethane/air peak at moderately rich mixtures (phi = 1.3) and the reactivity limits broaden in the presence of platinum plate compared to the gaseous flammability limits. The main products of burning these four hydrocarbon fuels over platinum are CO2 and H2O while CNG showing the highest selectivity to CO and H-2. Species such as methane (CH4), acetylene (C2H2), ethane (C2H6), dimethyl ether (C2H6O), propylene (C3H6), and propane (C3H8) appear in the products when burning LPG and butane over platinum. The streamwise profiles of species indicate the presence of two reacting zones along the plate which are described as: (i) the leading edge zone where high gradients of species mole fractions are observed and (ii) the trailing zone where the profiles are more flat and stable. The transverse profiles highlight the presence of two reactive layers: (i) the inner boundary where peaks of CO, CO2, and H-2 occur and (ii) the outer layer where formation of the other hydrocarbons is observed. Heavier alkanes result in oxygen/fuel ratio near the plate higher than those injected in the free stream and this may be largely due to differential molecular as well as thermal diffusion.
- 出版日期2013-3
