The Performance of a Type of Swirl Atomizer

Radcliffe, Alastair J.

doi:10.1243/pime_proc_1955_169_022_02

Cited by 40 publications

(8 citation statements)

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“…The dimensionless ow parameter that governs the ow phenomena in the nozzle is the Reynolds number. 16 The range of the Reynolds number based on the average axial velocity at the nozzle exit and the exit diameter was 2.7 £ 10 5 to 4 £ 10 5 in the large-scale experiments.This is similar to the range of the Reynolds number encountered in small-scale practical nozzles. Therefore, the preceding agreements validate the computational model at both large and small scale.…”

Section: Model Validationmentioning

confidence: 89%

Parametric Study of Simplex Fuel Nozzle Internal Flow and Performance

et al. 2000

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A numerical study is presented of the effects of changes in simplex nozzle geometry on its performance. A computational model based on the arbitrary-Lagrangian-Eulerianmethod with an adaptive grid-generation scheme is used. Three nondimensional geometric parameters are studied: the length-to-diameter ratio of the swirl chamber L s /D s and ori ce l o /d o and the swirl-chamber-diameter-to-exit-ori ce-diameter ratio D s /d o . The variations in the atomizer performance, caused by the changes in the geometric parameters, are presented in terms of the lm thickness at the exit of the ori ce, the spray cone angle, and the discharge coef cient. Results indicate that these geometric parameters have a signi cant effect on the internal ow and performance of simplex nozzles. With a constant mass ow through the nozzle over the range of parameters considered, an increase in L s /D s produces an increase in the lm thickness at the ori ce exit, a decrease in the spray cone half-angle, and a slight decrease followed by an increase in the discharge coef cient. Conversely, increasing l o /d o decreases lm thickness, spray cone angle, and discharge coef cient. An increase in D s /d o results in a decrease in lm thickness and discharge coef cient and a decrease in spray cone angle. Nomenclaturechamber diameter, m d o = exit-ori ce diameter, m K = atomizer geometric constant, A p / ( D s d o ) L s = swirl-chamber length, m l o = ori ce length, m m = vertex mass Çm = mass-ow rate, kg/s p = mean pressure, N/m 2 p 1 = ambient pressure, N/m 2 R 1 , R 2 = radii of curvature, m r = radial coordinate, m t = time, s t s = lm thickness, m t ¤ s = dimensionless lm thickness, t s / (d o / 2) u = axial velocity, m/s v = radial velocity, m/s w = swirl velocity, m/s x = axial coordinate, m D p = pressure differential, N/m 2 h = spray cone half-angle, deg l = dynamic viscosity, kg m/s l t = turbulent dynamic viscosity, kg m/s q = uid density, kg/m 3 r = surface tension, N/m

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Section: Model Validationmentioning

confidence: 89%

Parametric Study of Simplex Fuel Nozzle Internal Flow and Performance

et al. 2000

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“…However, external mixing atomizers have the advantage of producing sprays with constant spray angle at all liquid flow rates independently of the back pressure, as there is no communication between the flowing media internally. Undoubtedly, there are various ways to generate the atomized sprays using various types of nozzles, including, for example, rotary cups (Nguyen and Rhodes, 1998), twin fluids (Lefebvre, 1988;Wade et al, 1999;Li et al, 2018;Mujumdar et al, 2010;Esfarjani and Dolatabadi, 2009;Gadgil and Raghunandan, 2011;Huang et al, 2011;Loebker and Empie, 1997;Zhou et al, 2010), pressure swirl (Radcliffe, 1955;Dafsari et al, 2017;Arcoumanis et al, 1999a), fan (Dombrowski et al, 1960), ultrasonic (Lang, 1962), electrostatic (Maski and Durairaj, 2010), diesel injectors (Arcoumanis et al, 1999b;Mitroglou and Gavaises, 2011), and effervescent atomizers (Sovani et al, 2001;Saleh et al, 2018); solid or hollow cone sprays may form depending on the type of atomizer and operating conditions. However, in thermal power plants or oil-fired large industrial boilers, operating with high flow rates of viscous fuel, mostly Y-jet or internal mixing chamber twin-fluid atomizers are used (Barreras et al, 2006b).…”

Section: Introductionmentioning

confidence: 99%

The Influence of Geometrical and Operational Parameters on Internal Flow Characteristics of Internally Mixing Twin-Fluid Y-Jet Atomizers

et al. 2019

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Internally mixing twin-fluid Y-jet atomizers are widely used in coal-fired thermal power plants for start-up, oil-fired thermal power plants, and industrial boilers. The flow through internally mixing Y-jet atomizers is numerically modeled using the compressible Navier-Stokes equations; wall modeled large eddy simulations (WMLES) are used to resolve the turbulence with large eddy simulations whereas the Prandtl mixing length model is used for modeling the subgrid scale structures, which are affected by geometric and operational parameters. Moreover, the volume-of-fluid (VOF) method is used to capture the development and fragmentation of the liquid-gas interface within the Y-jet atomizer. The numerical results are compared with correlations available in the open literature for the pressure drop; further results are presented for the multiphase flow regime maps available for vertical pipes. The results show that the mixing point pressure is strongly dependent on the mixing port diameter to air port diameter ratio, specifically for gas to liquid mass flow-rate ratio (GLR) in the range 0.1 < GLR < 0.4; the mixing port length moderately affects the mixing point pressure while the angle between mixing and liquid ports is found not to have an appreciable effect. Moreover, it is found that the vertical pipe multiphase flow regime maps in the literature could be applied to the flow through the mixing port of the twin-fluid Y-jet atomizer. The main flow regimes found under the studied operational conditions are annular and wispy-annular flow.

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“…Numerous studies for the discharge coefficient have been published to account for the effect of liquid properties (16), operating conditions (17), atomizer geometry (18), vortex flow pattern (19), and conservation of axial momentum (20). From one analysis (21), the following empirical equation appears to correlate well with the actual data obtained for swirl atomizers over a wide range of parameters.…”

Section: Internal Flowmentioning

confidence: 99%

“…Some of the principal variables affecting the mean droplet diameters for pressure swirl atomizers may be expressed by equation 16. Equation 16 indicates that liquid pressure has a dominant effect in controlling the mean droplet sizes for pressure atomizers. The higher the liquid pressure, the finer the droplets are.…”

Section: Effect Of Variables On Mean Dropletmentioning

confidence: 99%

Sprays

Lipp

2006

Kirk-Othmer Encyclopedia of Chemical Technology

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Sprays are widely used in many industrial processes. In more recent years, the subject of liquid atomization has developed from a position of minor importance into a broad and significant technology. This article summarizes information and covers such topics as liquid atomizers, physics of atomization, spray characterization, instrumentation, and industrial applications. Atomizers have been summarized according to their sources of energy, distinct design features, and applications. Discussion of the physics of atomization is divided into three different regimes: internal flow, liquid breakup, and droplet dispersion. Spray characterization focuses on the explanation of common spray parameters, typical spray dynamic structures, effect of variables, and correlation techniques. Because of its important role, spray instrumentation is also discussed, along with an overview of representative optical and nonoptical techniques. Specific examples of industrial spray applications are cited and general comments are made regarding the methods selection of liquid atomizers and concerns related to their operation.

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The Performance of a Type of Swirl Atomizer

Cited by 40 publications

References 2 publications

Parametric Study of Simplex Fuel Nozzle Internal Flow and Performance

Parametric Study of Simplex Fuel Nozzle Internal Flow and Performance

The Influence of Geometrical and Operational Parameters on Internal Flow Characteristics of Internally Mixing Twin-Fluid Y-Jet Atomizers

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