Liquid-spray burning in the wake of a stabilizer disc

McCreath, C.G.; Chigier, Norman

doi:10.1016/s0082-0784(73)80121-3

Cited by 19 publications

(4 citation statements)

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“…The radial velocity values are found to be close to those of the axial velocity, signifying large spreading in the radial direction. Therefore, the droplets cross the gas separation streamline as in liquid spray burning in the wake of a stabiliser disk [22]. It may be observed that the droplets exhibit a radial velocity larger than the gas in the inner and outer regions.…”

Section: Gas and Drop Velocitiesmentioning

confidence: 99%

Measurements of droplets characteristics in a swirl-stabilized spray flame

Hadef

Lenze

2005

Experimental Thermal and Fluid Science

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Section: Gas and Drop Velocitiesmentioning

confidence: 99%

Measurements of droplets characteristics in a swirl-stabilized spray flame

Hadef

Lenze

2005

Experimental Thermal and Fluid Science

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“…The trajectories of droplets were found to depend on the prevailing aerodynamic conditions which can be varied by the combustor design and flow configuration [8,9]. In a swirling flame, smaller droplets are entrained by the recircultaing aerodynamic pattern with an aerodynamic blockage [8,10]. The mixing of droplets with oxidant and hot combustion products (on the macromixing scale) is augmented by recirculation and entrainment [3,11].…”

Section: Introductionmentioning

confidence: 99%

Investigation of liquid fuel combustion in a cross-flow burner

Kamal

Amohamad

2007

Proceedings of the Institution of Mechanical Engineers, Part A:

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A rotary swirl burner was employed for liquid fuel spray combustion in a cross-flow stream of air. The effect of fuel spray orientation on mixing dynamics with the swirled air was investigated for different nozzle angles, including -45°, 0°, and 45°, respectively, with a variable portion of the air (from 0 to 100 per cent) allowed to flow aligned with the spray without swirl. The effect of swirl on CO and NOx emissions was found to be dominated by the competitive influences of improved mixing and increased kinetic rates. For cross injector alignment with air, NOx emissions were reduced by increasing the co-current air flowdue to the improved premixing effect, while for inclined alignment its emissions exhibited a reduction by supplying enough air to the spray lee side. High swirl intensity (swirl number up to 12) and co-current/cross-flow combination produce a reduction in the unburned hydrocarbons. The enhancement in flame radiation output with swirl was pronounced by an increase to 1.9 times the output without swirl. Inserting a porous medium at the burner exit, increased the enhancement to 4.18 times and promoted droplet evaporation. Enlarging the re-circulation zone beneath the fuel injector to a certain extent improved mixing and combustion efficiency.

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“…Experiments in twophase reacting flows are even fewer in number and have communicated little of the quantitative understanding required to advance the processes of liquid-and solidfuel combustion. Exceptions include the work of McCreath & Chigier (1973), which made use of photographic techniques to characterize the behaviour of droplets in a flame, but without the required droplet size resolution, and the recent work of Mao et al (1986) and McDonell & Samuelsen (1988), which used similar techniques to those of this paper to measure the reacting and non-reacting characteristics of the two-phase near fields of air-assist and air-blast atomizers. In the present work, we have chosen to make use of phase-Doppler anemometry because it can, in principle, provide information of velocity and size characteristics.…”

Section: Introductionmentioning

confidence: 99%

Velocity and size characteristics of liquid-fuelled flames stabilized by a swirl burner

Hardalupas

Taylor

Whitelaw

1990

Proc. R. Soc. Lond. A

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Velocity and droplet size characteristics of an unconfined quarl burner, of 16 mm quarl inlet diameter, have been measured with a phase-Doppler anemometer at a swirl number of about 0.29: the Reynolds number of the flow was 30000, based on the cold bulk velocity of 30.4 m s -1 and the hydraulic diameter. The atomization was achieved by shear between the swirling air and six radial kerosene jets and the resulting Sauter and arithmetic mean diameters were about 70 and 50 μm respectively after injection: velocity characteristics are presented for three 5 μm-wide size classes, 10, 30 and 60 μm. The flows correspond to no combustion and combustion of natural gas with a heat release of 8 kW supplemented by liquid kerosene flow rates sufficient to generate 21.6 and 37.2 kW : the gas equivalence ratio was 0.45 and atomized kerosene at two flow rates increased the overall ratios to 1.64 and 2.53. In non-reacting flow, droplets 30 μm and smaller are sufficiently small to be entrained by the mean air velocity towards the central part of the flow and into the swirl-induced recirculating air bubble. The 60 μm droplets are able to travel through the bubble uninfluenced by turbulent fluctuations in the air and are ‘centrifuged’ away from the centreline, through acquisition of a mean swirl velocity component, so that a large proportion of the kerosene volume flow rate lies at the edge of the swirling jet. Because larger droplets are centrifuged to the outer part of the flow, whereas the smaller are entrained towards the centreline, the Sauter and arithmetic mean diameters are, by 1.22 quarl exit diameters downstream of the quarl, approximately 65 and 36 μm at the outer part of the flow and 35 and 12 μm near the centreline in the inert flow. In reacting flow, droplets evaporate rapidly in regions of elevated temperatures and hence no droplets are found within the flame brush and recirculation region. The aerodynamic response of each size class to the air velocity is similar to inert flow so that the majority of the kerosene flow is centrifuged away from the flame. On exit from the quarl, the evaporation and burning rates cause the Sauter and arithmetic mean diameters to be about 70 and 50 μm and 60 and 30 μm at the inner and outer edges of the spray respectively. By 1.22 quarl exit-diameters from the exit of the quarl, the air motion entrains droplets smaller than about 30 μm towards the flame, at the inner edge of the spray, so that the Sauter and arithmetic mean diameters are 60 and 40 μm at the outer edge of the jet. There is comparatively little effect of changing the flow rate of kerosene because the combustion is controlled by the low available number of smaller droplets, although the Group combustion number corresponds to ‘cloud’ burning. The relative response of droplets to the mean and turbulent components of air motion, including the ‘centrifuging’ effect, can be scaled to other flows through dimensionless numbers defined in the text.

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Liquid-spray burning in the wake of a stabilizer disc

Cited by 19 publications

References 1 publication

Measurements of droplets characteristics in a swirl-stabilized spray flame

Measurements of droplets characteristics in a swirl-stabilized spray flame

Investigation of liquid fuel combustion in a cross-flow burner

Velocity and size characteristics of liquid-fuelled flames stabilized by a swirl burner

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