Influence of Transverse Slot Jet on Premixed Flame Acceleration

摘要

This work aims to identify the key flow parameters that influence flame acceleration in a semiconfined squarechannel. A transverse fluidic jet was used as an active flow blockage mechanism and to introduce turbulence into thepropagating flame. Three experimental parameters were used to examine the relative influence of 1) mixturereactivity (defined here as system equivalence ratio, SER), 2) jet mixture composition (JMC), and 3) the momentumratio (MR) on the acceleration of laminar premixed methane flame. High-speed particle image velocimetry andschlieren photography were used to characterize the instantaneous flowfield conditions throughout the flame–jetinteraction. Using these diagnostic techniques, flame front positions and local velocity vector fields have been spatiallyand temporally resolved. Changes in flame properties, including flame structure, velocity, and vorticity, were trackedas functions of time. Stoichiometric equivalence ratios were more effective in the production of vorticity and thepromotion of flame acceleration. The stoichiometric condition accelerated the flame to the highest final flame velocityof the three parameters examined. Different compositions of the jet mixture demonstrated that the flame accelerationis primarily affected by the jet turbulence and not on the reactivity of the jet compositions. TheMRparameter had theleast amount of influence on the flowfield and flame acceleration. The increase of 33% in theMRhad negligible effecton the final flame front velocity and implies that the jet turbulence is the main driving mechanism for flameacceleration.