Pressure-Gradient Tailoring Effects On The Turbulent Flame-Vortex Dynamics Of Bluff-Body Premixed Flames

Keywords

Baroclinicity; Bluff-body premixed flames; Flame-vorticity dynamics; Turbulent premixed combustion

Abstract

This paper explores the effects of pressure-gradient tailoring on the turbulent flame and vorticity generation mechanisms of premixed flames. A turbulent premixed flame stabilized by a bluff-body in a high-speed combustor is used for the investigation. The combustor pressure gradient is altered using a variable-geometry test section. The turbulent flame-flow field is measured and characterized using simultaneous high-speed particle imaging velocimetry (PIV) and CH* chemiluminescence. A Lagrangian tracking technique is applied to analyze the details of the flame-vortex interactions from the experimental data. Lagrangian fluid elements are tracked as they evolve across the flame. The vorticity mechanisms are decomposed along the Lagrangian trajectories to determine their relative balance under various pressure gradient conditions. It is demonstrated that the induced pressure-gradient affects the relative magnitudes of combustion-generated dilatation and baroclinic torque, as well as the vortex stretching. An increase in the magnitudes of the vorticity mechanisms is shown with the largest gain in baroclinicity for the augmented pressure gradient relative to the attenuated.

Publication Date

11-1-2018

Publication Title

Combustion and Flame

Volume

197

Number of Pages

227-242

Document Type

Article

Personal Identifier

scopus

DOI Link

https://doi.org/10.1016/j.combustflame.2018.08.001

Socpus ID

85052308900 (Scopus)

Source API URL

https://api.elsevier.com/content/abstract/scopus_id/85052308900

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