Vortex Structure and Temperature Field in Transitional Diffusion flame Stabilized on Bluff-Body

摘要

Vortical and thermal structures of non-premixed propane flame in a bluff-body burner are studied experimentally in the transition from laminar to turbulent flow. In particular, we focus attention on the effect of annular air flow on the flame. The increase in the annular air flow promotes development of a shear vortex street in the central fuel jet and also leads to change in the direction of rotation of the shear vortex. The vortex dynamics correspond well to the fluctuation in temperature and there is a peak in rms temperature inside and outside the flame, respectively. It is revealed that the annular air flow has a stronger impact on the flame, rather than the central fuel jet, in this experimental range.