涡流稳定环形分层火焰特征的实验研究
Stereoscopic Planar Image Velocimetry (SPIV) has been applied to obtain the threecomponents of the instantaneous velocity vectors on a vertical plane above the burneroutlet where the flames propagate. The instantaneous temperature fields have beendetermined through Laser Induced Rayleigh (LIRay) scattering. Planar Laser InducedFluorescence (PLIF) on acetone has been used to calculate the average equivalence ratiodistributions. Instantaneous turbulent burning velocities have been extracted from SPIVresults, while flame curvature and flame thermal thickness values have been calculatedusing the instantaneous temperature fields. The probability distributions of thesequantities have been compared considering the separate influence of equivalence ratiostratification and turbulence. It has been observed that increased levels of turbulencedetermine higher turbulent burning velocities and flame front wrinkling. Flamescharacterized by stronger fuel stratification showed higher values in turbulent burningvelocities. From the curvature analysis emerged that increased fuel concentrationgradients favour flame wrinkling, especially when associated with positive small radiusof curvature. This determines an increased surface area available for reaction thatpromotes a faster propagation of the flame front in the oncoming combustible mixtures.