Mutual effects between a gliding arc(GA)discharge at atmospheric pressure and a premixed CH_(4)/air flame were experimentally investigated.Effects of the flame on the GA were studied using simultaneous measurements of...Mutual effects between a gliding arc(GA)discharge at atmospheric pressure and a premixed CH_(4)/air flame were experimentally investigated.Effects of the flame on the GA were studied using simultaneous measurements of the current,the voltage,and the instantaneous images of the plasma columns.The GA in the flame has a thicker and more diffusive plasma column,and it is more frequently ignited at a smaller breakdown voltage than that in the air.The GA extension velocity and the gliding velocity in the flame are larger than those in the air.The electrode voltage drop of the GA discharge in the flame is about 160 V,whereas that in the air is about 220 V.Compared with the GA in the air,the different features of the GA in the flame can be explained by high-temperature,weakly ionized,and species-abundant environment that are generated by the premixed CH_(4)/air flame.Effects of the gliding arc discharge on the premixed flames were demonstrated using planar laser-induced fluorescence of hydroxyl radicals(OH)and formaldehyde(CH_(2)O).OH and CH_(2)O can be formed in the CH_(4)/air mixture in the presence of the GA due to kinetic effects,and the increase of OH and CH_(2)O shows the great potential of the GA for combustion enhancement.展开更多
Planar laser-induced fluorescence (PLIF) was used to study the characteristics of pollutant mixing and transport in wakes behind peninsula-type bodies. Fluorescein sodium was introduced 40 cm upstream of the peninsul...Planar laser-induced fluorescence (PLIF) was used to study the characteristics of pollutant mixing and transport in wakes behind peninsula-type bodies. Fluorescein sodium was introduced 40 cm upstream of the peninsula as a tracer. The concentration field was measured behind semicircula-shape and sinusoid-shape peninsulas for steady inlet flows for a distance of seven radii downstream of the bodies. Analysis of the mean concentration and root mean square concentration fields showed that two factors mainly affected the concentration field in the near wake, the convection of pollutants with the main flow and the entrainment in the mixing shear layer. The impact of the shape on the concentration distribution is complex because of these two factors. In the present experiments, the semicircular peninsula caused better pollutant mixing, while the sinusoidal peninsula resulted in higher concentrations in the near wake region.展开更多
基金financially supported by National Natural Science Foundation of China(Nos.12172379,12322211,and 11925207)。
文摘Mutual effects between a gliding arc(GA)discharge at atmospheric pressure and a premixed CH_(4)/air flame were experimentally investigated.Effects of the flame on the GA were studied using simultaneous measurements of the current,the voltage,and the instantaneous images of the plasma columns.The GA in the flame has a thicker and more diffusive plasma column,and it is more frequently ignited at a smaller breakdown voltage than that in the air.The GA extension velocity and the gliding velocity in the flame are larger than those in the air.The electrode voltage drop of the GA discharge in the flame is about 160 V,whereas that in the air is about 220 V.Compared with the GA in the air,the different features of the GA in the flame can be explained by high-temperature,weakly ionized,and species-abundant environment that are generated by the premixed CH_(4)/air flame.Effects of the gliding arc discharge on the premixed flames were demonstrated using planar laser-induced fluorescence of hydroxyl radicals(OH)and formaldehyde(CH_(2)O).OH and CH_(2)O can be formed in the CH_(4)/air mixture in the presence of the GA due to kinetic effects,and the increase of OH and CH_(2)O shows the great potential of the GA for combustion enhancement.
基金Supported by the National Natural Science Foundationof China(No.5 0 0 790 10 )
文摘Planar laser-induced fluorescence (PLIF) was used to study the characteristics of pollutant mixing and transport in wakes behind peninsula-type bodies. Fluorescein sodium was introduced 40 cm upstream of the peninsula as a tracer. The concentration field was measured behind semicircula-shape and sinusoid-shape peninsulas for steady inlet flows for a distance of seven radii downstream of the bodies. Analysis of the mean concentration and root mean square concentration fields showed that two factors mainly affected the concentration field in the near wake, the convection of pollutants with the main flow and the entrainment in the mixing shear layer. The impact of the shape on the concentration distribution is complex because of these two factors. In the present experiments, the semicircular peninsula caused better pollutant mixing, while the sinusoidal peninsula resulted in higher concentrations in the near wake region.
