On the non-reacting flow and mixing fields of an axisymmetric disk stabilizer, under inlet mixture stratification and preheat

Abstract

The non-reacting, time mean and fluctuating flow field and the mixing characteristics of a bluff-body stratified flame stabilizer have been investigated for a range of inlet mixture compositions and preheat conditions. The burner consists of three concentric disks that form two premixing cavities. Tracer fuel is injected in the first cavity and is partially premixed with air flowing through the cavity system, resulting in a stratified equivalence ratio profile at the inlet of the stabilization region. The burner is capable of anchoring flames at very lean mixtures, down to Φ = 0.13 at 743 K. Particle Image Velocimetry (PIV) and Fourier Transform Infrared Spectroscopy (FTIR) analysis have been performed to evaluate the flow and mixing fields developing in the downstream near wake. Four levels of preheat of the incoming reactants, ranging from 300 to 743 K, for lean and ultra-lean, limiting, mixture levels have been selected. The impact of preheat on the developing disk wake topology and mixing performance has been examined and its operational parameters have been evaluated. Further, the study has helped to elucidate the effects of inlet mixture stratification, alone or in combination with preheat, on the performance characteristics of the disk stabilizer and to identify parameters that control mixture placement in the recirculation zone.