Bunsen flame hydrodynamics

Wagner, Terrance C.; Ferguson, Colin R.

doi:10.1016/0010-2180(85)90130-0

Cited by 17 publications

(5 citation statements)

References 7 publications

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“…Figure 6(a) also shows a very slight drop in velocity between the burner exit and the plane z = 4 mm, related to the outwards deflection of the streamlines in the boundary layer, mentioned above. This has also been observed by previous authors (Wagner & Ferguson 1985;Baillot et al 1992). Figure 6(b) shows that the radial profiles of the axial velocity at z = 1.5 mm are quite flat over the whole section.…”

Section: Flow With a Flame 321 No Acoustic Excitationsupporting

confidence: 88%

On the shape of flames under strong acoustic forcing: a mean flow controlled by an oscillating flow

et al. 1997

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A conical flame, in the presence of high-frequency (≈1000 Hz) and high-amplitude acoustic modulation of the cold gases, deforms to a shape which is approximately hemispherical. It is shown that the acoustic level required to produce a hemispherical flame is such that the ratio of acoustic velocity to laminar combustion velocity is about 3. This flame flattening is equivalent to the phenomenon of acoustic restabilization observed for cellular flames propagating in tubes. The transition between the conical flame and a hemispherical flame is described. The surface area of the reaction zone of the flame is found to be unmodified when the flame flattens. The velocity field at the burner outlet is examined with and without a flame. The mean flow lines are strongly deflected when the hemispherical flame is present. We show that the presence of the flame creates an unusual situation where the oscillating flow controls the geometry of the mean flow.

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Section: Flow With a Flame 321 No Acoustic Excitationsupporting

confidence: 88%

On the shape of flames under strong acoustic forcing: a mean flow controlled by an oscillating flow

et al. 1997

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“…The flame on the other hand shows an increase of 15% in the tip vicinity with a subsequent decay to about 75% past the flame tip. Comparable results have been found by Echekki and Mungal (1990) Wagner and Ferguson (1985), who also performed L D V measurements in a round Bunsen flame; they report a gradual decay of the mean centerline velocity in the potential region, followed by the sudden rise and subsequent decay at the tip. Wagner and Ferguson conclude that the presence of the flame affects the entire flowfield, while the present results suggest that the region of influence is more limited and extends primarily to the preheat zone.…”

Section: Laminar Flamessupporting

confidence: 74%

Instantaneous Velocity Measurements in Laminar and Turbulent Premixed Flames Using On-Line PIV

Mungal

Lourenco

Krothapalli

1995

Combustion Science and Technology

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AB!STRACT-Particle Image Velocirnetry (PIV) is used to measure the instantaneous velocity field in laminar and turbulent premixed flames formed at the exit of a round Bunsen burner. The seeding levels were adjusted to provide data simultaneously in the unburne~d as well as burned gases. The PIV system employs a double-pulsed laser with a solid state sensor as the recording device. Customized image acquisition is used to quickly process the data, thus rapidly providing the velocity field. Two-dimensional, instantaneous velocity fields are measured in a steady laminar flame and capf.ures the sudden change in flow speed at the flame sides as well as the high speeds sustainable at the flame lip. Pi wake profile downstream of the flame cone is revealed. Vorticity, strain rates and dilatation are possible with these datasets and are also reported; the strain rate is seen to be a reasonably good approxinxltion to the flame shape with magnitudes measured to be below the extinction stretch rate; the dilatation is seen to provide the closest approximation to the instantaneous flame shape. Turbulent flame tips show similar phenomena occurring instantaneously on convoluted flame shapes. The overall accuracy of the measurements is discussed.

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“…This phenomenon may be due to a nozzle effect caused by the heating of the burner which is attenuated with y. This has been already observed in a laminar steady case [30] and in a turbulent case as well [31]. For y  10 mm, regard of excitation frequency used, an increase is observed, possibly due to expansion effects of gases.…”

Section: Unburned Gases Zonementioning

confidence: 64%