Experimental Study on Turbulent Structure of Humid Air Flame in a Bluff-body Burner

The main objective of the present experimental study is to analyze the turbulent structure in humid air non-premixed flame, and determine the effect of humidity oil the flow field and the flame stability limit in turbulent non-premixed flame. Particle Image Velocimetry (PIV) is used to capture the instantaneous appearance of vortex structures and obtain the quantitative velocity field. The distributions of Reynolds shear stress, mean and root-mean Squared fluctuating (rms) velocities are examined to get insight into the effect of fuel-to-air velocity ratio on velocity flow field. The results show that with steam addition, the air-driven vortex in the bluff-body wake is thinner; the biggest peaks of rms velocity and Reynolds shear stress are lower: the distance between the peaks of rills velocity oil the sides of centerline reduces. Besides these, the flame stability is affected. Both central fuel penetration limit and partially quenching limit reduce with steam addition.