Bluff-body flame stabilization: Blockage effects

Wright, F. Howell

doi:10.1016/0010-2180(59)90035-5

Cited by 54 publications

(19 citation statements)

References 2 publications

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“…In region 1, increase in BR decreases the pressure coefficient. For region 2, we observe a slight decrease in the recirculation zone length with increasing BR, an observation in line with the results of Winterfeld (1965) and Wright (1959). Finally, in region 3, the acceleration of the flow is relatively greater with higher BR.…”

Section: Resultssupporting

confidence: 89%

Aerodynamics of Bluff Body Stabilized Confined Turbulent Premixed Flames

Pan

Vangsness

Ballal

1991

Volume 3: Coal, Biomass and Alternative Fuels; Combustion and Fuels; Oil and Gas Applications; Cycle Innovations

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Detailed information on the influence of geometric and flow parameters on the structure and properties of recirculation zone in confined combusting flows is not available. In this paper, recirculation zone structure and turbulence properties of methane-air mixtures downstream of several conical flameholders were measured using LDA. These tests employed different blockage ratios (13% and 25%), cone angles (30, 45, 60, and 90 degrees), equivalence ratios (0.56, 0.65, 0.8, and 0.9), mean annular velocities (10, 15, and 20 m/s), and approach turbulence levels (2%, 17%, and 22%). It was found that increasing the blockage ratio and cone angle affected the recirculation zone size and shape only slightly. Also, these parameters increased the shear stress and turbulent kinetic energy (TKE) moderately. Increasing the equivalence ratio or approach turbulence intensity produced a recirculation zone shape very similar to that found in the cold flow. TKE decreased due to turbulent dilatation produced by increased heat release. These observations are discussed from the viewpoint of their importance to practical design and combustion modeling.

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Section: Resultssupporting

confidence: 89%

Aerodynamics of Bluff Body Stabilized Confined Turbulent Premixed Flames

Pan

Vangsness

Ballal

1991

Volume 3: Coal, Biomass and Alternative Fuels; Combustion and Fuels; Oil and Gas Applications; Cycle Innovations

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“…This latter result is consistent with others studies, see Radhakrishnan et al [12] (these authors also conclude that the length of the recirculation zone leads to a tighter data grouping than the characteristic flameholder width). Fourth, the need to incorporate compressibility effects into the lip velocity calculation for higher Mach number/blockage ratios, noted by Wright [93], was clearly seen by comparing these correlations with and without compressibility corrections. Fifth, systematic differences in Reynolds number scaling can be seen between twodimensional and axisymmetric bluff bodies.…”

Section: Correlation Resultsmentioning

confidence: 93%

Lean blowoff of bluff body stabilized flames: Scaling and dynamics

Shanbhogue

Husain

Lieuwen

2009

Progress in Energy and Combustion Science

529

206

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“…Further studies focused mostly on the flame stability limits, as well as on the stability mechanisms involved in the combustion process 2,6,7 . The studies measured the influence of the inflow velocity, blockage ratio and flame stabilizer shape on the geometry of the back-flow region, the residence time, the mean exchange velocity through the shear layer and the level of turbulence intensity at the recirculation region boundary.…”

Section: Introductionmentioning

confidence: 99%

Experimental Measurements in Reactive and Non-Reactive Turbulent Flows

Florean¹,

Petcu²,

Porumbel³

et al. 2012

48th AIAA/ASME/SAE/ASEE Joint Propulsion Conference &Amp;amp; Exhibit

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The paper presents experimental velocity measurements in the reactive and nonreactive flow behind a bluff body that acts as a flame stabilizer in a post-combustion chamber, as well as in the free exhaust jet of the gas generator upstream of the postcombustion system. The velocity measurements were conducted using Particle Image Velocimetry (PIV). The paper presents both the average, three-dimensional velocity field, and the turbulent velocity fluctuations of two meaningful velocity components. The experimental setup and the PIV measurement installation that have been used for the presented measurements are also briefly described. Nomenclature c = spreading constant for round turbulent jets u = axial velocity component v = transversal velocity component w = spanwise velocity x = axial spatial coordinate y = transversal spatial coordinate z = spanwise spatial coordinate I. Introduction HE usual flow velocity in an afterburner is several orders of magnitude higher than the highest flame speed for all practical fuels. Hence, some form of flame stabilization is needed to maintain combustion over the entire flight envelope. Over most of the flight regimes, the incoming temperature of the unburned mixture is much lower than the auto-ignition point, so a heat source must be provided for the ignition to occur. Also, the residence time of the unburned mixture in the high temperature region must be long enough to allow complete combustion in a compact physical device.

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Bluff-body flame stabilization: Blockage effects

Cited by 54 publications

References 2 publications

Aerodynamics of Bluff Body Stabilized Confined Turbulent Premixed Flames

Aerodynamics of Bluff Body Stabilized Confined Turbulent Premixed Flames

Lean blowoff of bluff body stabilized flames: Scaling and dynamics

Experimental Measurements in Reactive and Non-Reactive Turbulent Flows

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