Title

On The Fluid Dynamics Of Acoustically Perturbed Non-Premixed Swirling Flames

Abstract

An atmospheric burner is used in the present investigation to study the fluid dynamics associated with acoustically perturbed swirling flames. The fluid dynamics is studied in a cold flow (no flame) configuration with fuel and air flow rates previous established for stable flames. The fluid dynamics of the cold flow field is analyzed using the Particle Image Velocimetry (PIV) technique with Di-Ethyl-Hexyl-Sebacat (DEHS) as the seeding medium. The PIV studies are carried out with an Nd:YAG Litron PIV Nano Laser with a 532nm beam passed through cylindrical lenses to create a laser sheet through the central plane of the swirl stabilized burner. The primary elements of the burner include a central pipe through which propane is supplied, surrounded by an annulus through which air is supplied in the axial direction. The degree of swirl in the burner is characterized by the swirl number (S) provided by azimuthally distributed ports supplying air flow tangential to the main axially directed flow. Experiments are carried out for various swirl intensities (S=0.09, 0.28 and 0.34) at a Reynolds number of 3000 based on the burner exit diameter (d). With a speaker at the base of the burner, the flow field is acoustically perturbed at selected pulsing frequencies (f) expressed in non-dimensional form using the Strouhal Number (St) defined as St = fd / Uavg. The average velocity (Uavg) at the burner exit is determined using a hot wire anemometer. The dependence of the observed velocity and vorticity fields, strain rates, vortex size and roll-up on the pulsing frequency and swirl intensity are discussed Finally, the observed results are correlated with CH chemiluminescence imaging, frequency and continuous wavelet spectra from prior experimental analysis where the flame was present.

Publication Date

1-1-2009

Publication Title

Fall Meeting of the Eastern States Section of the Combustion Institute 2009

Number of Pages

720-725

Document Type

Article; Proceedings Paper

Personal Identifier

scopus

Socpus ID

84946594823 (Scopus)

Source API URL

https://api.elsevier.com/content/abstract/scopus_id/84946594823

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