Method for generating equilibrium swirling inflow conditions

Pierce, Charles D.; Moin, Parviz

doi:10.2514/3.13970

Cited by 30 publications

(45 citation statements)

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“…1. Just as the reverseflow cyclone, it has a tangential inlet which can be directly incorporated in the simulation procedure, thereby avoiding the need to separately generate swirl-inflow conditions, such as done by Pierce and Moin [12] in the context of their LES. In contrast to the reverse flow generated in the cyclone, the vortex tube facility generates a unidirectional flow.…”

Section: Introductionmentioning

confidence: 99%

Simulations of confined turbulent vortex flow

Derksen

2005

Computers & Fluids

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Large-eddy simulations (LES) of the turbulent flow in a swirl tube with a tangential inlet have been performed. The geometry, and flow conditions were chosen according to an experimental study by [Escudier MP, Bornstein J, Zehnder N. Observations and LDA measurements of confined turbulent vortex flow. J Fluid Mech 1980;98:49-63]. Lattice-Boltzmann discretization was used to numerically solve the Navier-Stokes equations in the incompressible limit. Effects of spatial resolution and choices in subgridscale modeling were explicitly investigated with the experimental data set as the testing ground. Experimentally observed flow features, such as vortex breakdown and laminarization of the vortex core were well represented by the LES. The simulations confirmed the experimental observations that the average velocity profiles in the entire vortex tube are extremely sensitivity to the exit pipe diameter. For the narrowest exit pipe considered in the simulations, very high average velocity gradients are encountered. In this situation, the LES shows the most pronounced effects of spatial resolution and subgrid-scale modeling.

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Section: Introductionmentioning

confidence: 99%

Simulations of confined turbulent vortex flow

Derksen

2005

Computers & Fluids

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“…The founder idea of large eddy simulation (LES) is to resolve the large turbulent motions in a flow field and to modeling only the effects of small ones. The resolved contribution ̅ is obtained by applying the spatial LES filter to instantaneous variables f. Filtering the instantaneous governing equations and introducing the Favre filtered variables /   ff [17][18].…”

Section: Mathematical Formulationmentioning

confidence: 99%

“…Once the CTRZ is established, it anchors the flame, thus improving the flame stabilization by returning hot gases and active radicals back to the jet core leading to a more stirred mixture. The shear layer between this recirculation zone and the main flow zone also generates great amount of turbulent energy, which intensifies the air-fuel mixing process and therefore improves the combustion efficiency, reduces the flame length, and lowers significantly the emission of NOx [14][15][16][17][18][19].…”

Section: Introductionmentioning

confidence: 99%

Numerical study of the swirl direction effect at the turbulent diffusion flame characteristics

Lalmi¹,

Hadef²

2017

IJHT

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The paper presents a numerical prediction of reacting flow field and temperature distribution of turbulent diffusion flame in two air blast nozzle swirling flow namely co and counter with different swirl intensities. This quantity is 0.46 for the central flow and ± 1.0 for the annular flow. Current study was focus on the rotation effect of the secondary flow. The calculated results were validated on real time through laser anemometry for both cases. The reasons behind the choice of this issue is that it is realistic in the industry but with a larger scale and our possession of the experimental values to validate the simulation. The use of two flows produced less NOx than a single flow due to its high capacity which homogenizes the temperature in the burner. The obtained results show that LES had successfully predicted the recirculation zones (CTRZ and CRZ) and the PVC with good precision.

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“…In both cases of N29S054 and N16S159, the top-hat profile at the inflow boundary remains to exist in a smaller extent in the numerical re-sults. In order to address this kind of difficulty in specifying the boundary condition at the inflow, Pierce and Moin (9), (10) used the LES of the flow in the coaxial annular duct to generate the swirl inflow condition, and analyzed the combustor with swirler. In these problem setup, however, the flow field which stipulates the inflow boundary condition is not independent of the combustion flow field with swirl under discussion, and they are mutually and simultaneously dependent, so this technique is not a perfect solution.…”

Section: Velocity Fieldmentioning

confidence: 99%

Large Eddy Simulation of Swirling Jet in a Bluff-Body Burner

Fujimoto

Yamasaki

2006

JSME international journal. Ser. B, Fluids and thermal engineer

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The large eddy simulation (LES) is applied to an unconfined swirling flow of an air surrounding a bluff-body having a central jet of air, and the complicated flow field that involves the recirculation and vortex breakdown is investigated. The Smagorinsky model is used as the sub-grid scale model. The results of the present numerical simulation are compared with the experimental data of the mean and stochastic root mean square (RMS) variations of two velocity components. Although the inflow conditions are specified in a simple manner, the obtained numerical results are in a reasonable agreement with the experiments, except for a part of RMS variation values behind the bluff body. The present numerical calculations can successfully reproduce the characteristics of the flow, i.e., an upstream recirculation region established just downstream of the burner plane. Additionally, the flow field is much different by the swirl number and axial velocity of the primary swirling air. Especially the additional recirculation region is established at the more downstream location in the lower swirl number and higher axial velocity of the primary swirling air.

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Method for generating equilibrium swirling inflow conditions

Cited by 30 publications

References 0 publications

Simulations of confined turbulent vortex flow

Simulations of confined turbulent vortex flow

Numerical study of the swirl direction effect at the turbulent diffusion flame characteristics

Large Eddy Simulation of Swirling Jet in a Bluff-Body Burner

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