Effect of non-uniform inlet velocity profile on flow field characteristics of a bluff body

Abstract

To explore the influence of the non-uniform inlet velocity profile of the bluff body on flame stabilization, PIV measurements are carried out to investigate the characteristics of the flow field at 300 K and 0.101 MPa with seven velocity profiles, including four-velocity peaks, h/H, and three non-uniformities, δv. The experimental results indicate that the recirculation is approximately symmetric with the non-interfering dual-vortex structure under the condition of uniform inlet flow, whereas it is asymmetric and the fluid flows from one vortex core into another one when the velocity peak rises. The tendency of the dual-vortex interaction becomes more pronounced with the increase of the non-uniformity and the velocity peak. Besides, the length of the recirculation zone increases with the increase of h/H, while the largest width occurs at h/H = 0 and 4/6. At the same time, the distance of one core decreases first and then increases, while the other one is opposite to that. The width of the recirculation zone along the x-axis corresponding to δv = 30% is the same as that at δv = 0, and its value is higher than that at δv = 40% and 50%.