The flow field structure at the base of lifted turbulent partially premixed jet flames

摘要

The flow field and reaction zone structure at the stabilization point of turbulent partially premixed lifted methane flames have been investigated based on advanced laser-based imaging techniques. Planar imaging velocimetry technique, PIV, is used for the flow, field and laser induced predissociation fluorescence technique, LIPF, is used for OH radical. The techniques are used to explore the stabilization mechanism at the base of three turbulent partially premixed methane lifted flames. The partially premixed mixture is created in a concentric tube burner. Velocity field and conditioned velocity at the flame base for different exit jet velocities and equivalence ratio have been investigated and discussed in this work. The data show that the flames stabilize at a position with an almost similar flow field structure. In addition, velocity profiles across the flame front at its base are quite similar to that of laminar triple flames. According to the present and our previous measurements in lifted turbulent partially premixed flames the stabilization mechanism is likely to be controlled by premixed flame propagation with triple flame structure at the base of the flames. This supports the application of triple flame structure model as a base for turbulent partially premixed flames at the stabilization position. (C) 2004 Elsevier Inc. All rights reserved.