Numerical prediction of turbulent flow in a conical diffuser usingk-ε model

Yongsen, He; Kobayashi, Toshio; Morinishi, Yohei

doi:10.1007/bf02487158

Cited by 5 publications

(8 citation statements)

References 3 publications

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“…The two‐order PDE with the characteristics of turbulent flow can be used to adjust the grid. The equation is the inverse transformation equation of the two‐order PDE …”

Section: Construction Of the 5‐point‐dd Difference Schemes For Dlr K−mentioning

confidence: 99%

“…Yongsen et al have done a lot of meaningful work in numerical prediction of turbulent flow in mechanical tubes. In the engineering applications of numerical simulation for turbulent flow, how to construct good difference schemes with high efficiency in time and high precision in space is a valuable research issue for many researchers.…”

Section: Introductionmentioning

confidence: 99%

“…However, the difference node template of good difference schemes in space should be a simple form, and the large banded sparse matrix has less bandwidth, which can be more efficient for solving various algebraic discrete system. The DLR k − ε turbulent model is a kind of two‐equation model designed for the prediction of turbulent flow in the conical diffuser. This turbulent model is especially suitable for the numerical simulation of incompressible viscous turbulence in an axisymmetric case.…”

Section: Introductionmentioning

confidence: 99%

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Convergence of five‐point scheme with diagonally dominant characteristic for DLR k−ε model and its application

Guang-biao

Shu

Yongsen

et al. 2019

Numerical Methods in Fluids

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In this paper, the equivalent equations of DLR k − turbulent model in the boundary-fitted curvilinear coordinate are employed. Using the upwind idea that the contribution of the difference coefficients to the main node is positive contribution, and the other nodes are negative contribution or no contribution, new five-point difference schemes with a full diagonally dominant coefficient matrix (5-point-DD difference scheme) are constructed. Finally, taking the u equation in the DLR k− turbulent model as an example, the mathematical characteristics of the 5-point-DD difference scheme are analyzed, and the uniform boundedness and convergence theorems of the Gauss-Seidel iterative sequence are given. Numerical simulations show that the five-point schemes are strictly diagonally dominant, and the calculated results are in good agreement with the experimental results. KEYWORDS conical diffuser, convergence, DLR k − turbulent model, strictly diagonally dominant matrix, 5-point-DD difference scheme Int J Numer Meth Fluids. 2020;92:189-211.wileyonlinelibrary.com/journal/fld

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“…The two‐order PDE with the characteristics of turbulent flow can be used to adjust the grid. The equation is the inverse transformation equation of the two‐order PDE …”

Section: Construction Of the 5‐point‐dd Difference Schemes For Dlr K−mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Convergence of five‐point scheme with diagonally dominant characteristic for DLR k−ε model and its application

Guang-biao

Shu

Yongsen

et al. 2019

Numerical Methods in Fluids

Self Cite

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“…The inlet cylindrical part has a diameter ref = 50.8 mm. of the TKE and the energy dissipation rate taken from [5] have been also set on the INLET. On the OUTLET, the kinematic pressure has been set to 0 m 2 s −2 , while for the other quantities a zeroGradient boundary condition has been used.…”

Section: Geometry and Boundary Conditions Of Test Casementioning

confidence: 99%

“…For these reasons it can be expected that − turbulence model gives good results here. Yongsen et al [5] performed 2D numerical flow simulations in the Azad's diffuser using standard − turbulence model and coarse computational mesh. They achieved good results under assumption of axisymmetric steady-state flow conditions in this diffuser.…”

Section: Introductionmentioning

confidence: 99%

On the influence of turbulent kinetic energy level on accuracy of k − ε and LRR turbulence models

Novkovic

Burazer²,

Ćoćić³

et al. 2018

Theor appl mech (Belgr)

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This paper presents research regarding the influence of turbulent kinetic energy (TKE) level on accuracy of Reynolds averaged Navier-Stokes (RANS) based turbulence models. A theoretical analysis of influence TKE level on accuracy of the RANS turbulence models has been performed according to the Boussinesq hypothesis definition. After that, this theoretical analysis has been investigated by comparison of numerically and experimentally obtained results on the test case of a steady-state incompressible swirl-free flow in a straight conical diffuser named Azad diffuser. Numerical calculations have been performed using the OpenFOAM CFD software and first and secondorder closure turbulence models. TKE level, velocity profiles and Reynolds stresses have been calculated downstream in four different cross sections of the diffuser. Certain conclusions about modeling turbulent flows by − and LRR turbulence models have been made by comparing the velocity profiles, TKE distribution and Reynolds stresses on the selected cross sections.2010 Mathematics Subject Classification: 76F10.

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Three-dimensional simulation of wind tunnel diffuser to study the effects of different divergence angles on speed uniform distribution, pressure in outlet, and eddy flows formation in the corners

Moradi

Nguyen

et al. 2020

Physics of Fluids

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Despite the widespread use of diffusers in various industries, there is no comprehensive research so far. This is expressive on how the flow diffuses throughout the diffuser geometry, the amount of non-uniformity of speed distribution at the outlet, and the rate of eddy flows at the corners. The present study simulated a three-dimensional diffuser with a square geometry at different divergence angles in order to obtain a better understanding of the flow diffusion across the geometry, velocity distribution at the outlet, and reverse flow. Moreover, the aspect ratio and the Reynolds number were considered constant in all cases. The turbulence model was used along with a high-resolution discretization and a root-mean-square convergence criterion to solve this problem. The speed was substantially reduced to nearly zero at corners of the diffuser with a square cross section. Reverse flow and eddy currents were also observed in the same regions. By increasing the divergence angle, this effect was further intensified, and in addition to the corners, flow separation and eddy currents were formed in the regions close to the wall due to the adverse pressure gradient. The maximum velocity and flow distribution at the outlet cross section was located in the central region, which was intensified by increasing the divergence angle. The deviation of the average velocity at the diffuser outlet with a divergence angle of 5°, with a completely uniform velocity distribution at the outlet, was observed to be 15.3%. This deviation grew with an increase in divergence angle and reached 128.9% at a divergence angle of 30°.

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Numerical prediction of turbulent flow in a conical diffuser usingk-ε model

Cited by 5 publications

References 3 publications

Convergence of five‐point scheme with diagonally dominant characteristic for DLR k−ε model and its application

Convergence of five‐point scheme with diagonally dominant characteristic for DLR k−ε model and its application

On the influence of turbulent kinetic energy level on accuracy of k − ε and LRR turbulence models

Three-dimensional simulation of wind tunnel diffuser to study the effects of different divergence angles on speed uniform distribution, pressure in outlet, and eddy flows formation in the corners

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