Velocity Distribution in an Abruptly Expanding Circular Duct

Moon, L. F.; Rudinger, George

doi:10.1115/1.3448527

Cited by 71 publications

(16 citation statements)

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“…Several previous experimenters have investigated nonreacting flows in expansion geometries [11][12][13][14][15][16][17][18][19][20]. References [11] and [12] also include flowfield predictions, made with versions of the TEACH-T computer program [7].…”

Section: Experimental Approachmentioning

confidence: 99%

On the Prediction of Swirling Flowfields Found in Axisymmetric Combustor Geometries

Rhode

Lilley

McLaughlin

1982

Journal of Fluids Engineering

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Combustor modeling has reached the stage where the most useful research activities are likely to be on specific sub-problems of the general three-dimensional turbulent reacting flow problem. The present study is concerned with a timely fluid dynamic research task of interest to the combustor modeling community. Numerical computations have been undertaken for a basic two-dimensional axisymmetric flowfield which is similar to that found in a conventional gas turbine combustor. A swirling nonreacting flow enters a larger chamber via a sudden or gradual expansion. The calculation method includes a stairstep boundary representation of the expansion flow, a conventional k-e turbulence model and realistic accommodation of swirl effects. The results include recirculation zone characterization and predicted mean streamline patterns. In addition, an experimental evaluation using flow visualization of neutrally-buoyant helium-filled soap bubbles is yielding very promising results. Successful outcomes of the work can be incorporated into the more combustion-and hardware-oriented activities of gas turbine engine manufacturers, including incorporating the modeling aspects into already existing comprehensive numerical solution procedures.

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Section: Experimental Approachmentioning

confidence: 99%

On the Prediction of Swirling Flowfields Found in Axisymmetric Combustor Geometries

Rhode

Lilley

McLaughlin

1982

Journal of Fluids Engineering

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“…One of the most effective ways to stabilize a flame in a combustor is by creating a recirculation zone through sudden expansion of the geometry as investigated by numerous experimental and numerical studies [8,9]. These studies indicated that local heat transfer coefficients for separated and reattached flows in suddenly expanding ducts are significantly larger than those for fully developed flows especially at the reattachment point.…”

Section: Introductionmentioning

confidence: 98%

A three-dimensional computational model of H2–air premixed combustion in non-circular micro-channels for a thermo-photovoltaic (TPV) application

2015

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“…Pitz and Daily 5 investigated the reacting flowfield following a 2-D step. Stevenson et al 6 reviewed a number of axisymmetric sudden expansion flow investigations including those of Freeman 7 and Moon and Rudinger, 8 which were the first in which LDV measurements were reported. Freeman's work was conducted with water, whereas Moon and Rudinger used air as the working medium.…”

Section: Introductionmentioning

confidence: 98%

Investigation of turbulent transport in an axisymmetric sudden expansion

1990

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Simultaneous two-component laser velocimeter measurements were made in the incompressible turbulent flowfield following an axisymmetric sudden expansion. Mean velocities, Reynolds stresses, and triple products were measured and are presented at axial positions ranging from x/H = 0.2-14. A balance of the turbulent kinetic energy in the flow was performed. The production, convection, and diffusion of turbulent kinetic energy were computed directly from the experimental data using central differencing. A specially designed correction lens was employed to correct for optical aberrations introduced by the circular tube. This lens system allowed the accurate simultaneous measurement of axial and radial velocities in the test section. The experimental measurements were compared to predictions generated by a code that employed the k-e turbulence model. Agreement was good for mean axial velocities, turbulent kinetic energy, and turbulent shear stresses. However, the modeled turbulent normal stresses where in poor agreement with the measured values. The modeled diffusion of turbulent kinetic energy was underpredicted in the region between the shear layer and the centerline of the flow giving lower values of turbulent kinetic energy downstream of the potential core than measured. NomenclatureC D = turbulence constant, =0.09 H -step height, 38.1 mm _ _ __ k = turbulent kinetic energy, = (uu + vv + ww)/2 / = mixing length, mm P = time-averaged mean static pressure, N/m 2 p = pressure fluctuation about time-averaged mean, N/m 2 RI = inlet radius of sudden expansion, 38.1 mm R 2 = outlet radius of sudden expansion, 76.2 mm r = radial coordinate direction, ( = 0 at centerline) U = time-averaged mean axial velocity, m/s UQ = inlet reference velocity, 22 m/s u_ -fluctuating axial velocity, m/s up = time-averaged axial velocity-ressure correlation, __ N/m-s uju -time-averaged axial turbulent normal stress, m 2 /s 2 uv = time-averaged turbulent shear stress, m 2 /s 2 uuu = turbulent triple product, mVs 3 uuv -turbulent triple product, mVs 3 uvv = turbulent triple product, mVs 3 V -time-averaged mean radial velocity (positive toward wall), m/s v_ = fluctuating radial velocity, m/s vp = time-averaged radial velocity-pressure correlation, N/ _ m-s vv = time-averaged radial turbulent normal stress, m 2 /s 2 vvv = turbulent triple product, mVs 3 w = fluctuating tangential velocity, m/s ww = time-averaged tangential turbulent normal stress, mVs 2 x = axial coordinate direction y = radial coordinate direction, ( = 0 at centerline) e = dissipation of turbulent kinetic energy, m 2 /s 3 fji = dynamic viscosity, Kg/m-s JLI, = turbulent viscosity, Kg/m-s /Xeff = effective viscosity, Kg/m-s p = fluid density, kg/m 3 o = standard deviation

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Velocity Distribution in an Abruptly Expanding Circular Duct

Cited by 71 publications

References 0 publications

On the Prediction of Swirling Flowfields Found in Axisymmetric Combustor Geometries

On the Prediction of Swirling Flowfields Found in Axisymmetric Combustor Geometries

A three-dimensional computational model of H2–air premixed combustion in non-circular micro-channels for a thermo-photovoltaic (TPV) application

Investigation of turbulent transport in an axisymmetric sudden expansion

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