燃烧,火焰,分层火焰,涡流中速度场,流场,速度矢量场检测方案(粒子图像测速)

Stereoscopic Planar Image Velocimetry (SPIV) has been applied to obtain the three components of the instantaneous velocity vectors on a vertical plane above the burner outlet where the flames propagate. The instantaneous temperature fields have been determined through Laser Induced Rayleigh (LIRay) scattering. Planar Laser Induced Fluorescence (PLIF) on acetone has been used to calculate the average equivalence ratio distributions. Instantaneous turbulent burning velocities have been extracted from SPIV results, while flame curvature and flame thermal thickness values have been calculated using the instantaneous temperature fields. The probability distributions of these quantities have been compared considering the separate influence of equivalence ratio stratification and turbulence. It has been observed that increased levels of turbulence determine higher turbulent burning velocities and flame front wrinkling. Flames characterized by stronger fuel stratification showed higher values in turbulent burning velocities. From the curvature analysis emerged that increased fuel concentration gradients favour flame wrinkling, especially when associated with positive small radius of curvature. This determines an increased surface area available for reaction that promotes a faster propagation of the flame front in the oncoming combustible mixtures.