CFD simulation of an unbaffled stirred tank reactor driven by a magnetic rod: assessment of turbulence models

2015 ◽  
Vol 72 (8) ◽  
pp. 1308-1318 ◽  
Author(s):  
Jiajia Li ◽  
Baoqing Deng ◽  
Bing Zhang ◽  
Xiuzhong Shen ◽  
Chang Nyung Kim
Keyword(s):  
Cfd Simulation ◽  
Tangential Velocity ◽  
Turbulence Models ◽  
Computational Effort ◽  
Stirred Tank ◽  
Detached Eddy Simulation ◽  
Stirred Tank Reactor ◽  
Tank Reactor ◽  
Eddy Simulation ◽  
Les Model

A simulation of an unbaffled stirred tank reactor driven by a magnetic stirring rod was carried out in a moving reference frame. The free surface of unbaffled stirred tank was captured by Euler–Euler model coupled with the volume of fluid (VOF) method. The re-normalization group (RNG) k–ɛ model, large eddy simulation (LES) model and detached eddy simulation (DES) model were evaluated for simulating the flow field in the stirred tank. All turbulence models can reproduce the tangential velocity in an unbaffled stirred tank with a rotational speed of 150 rpm, 250 rpm and 400 rpm, respectively. Radial velocity is underpredicted by the three models. LES model and RNG k–ɛ model predict the better tangential velocity and axial velocity, respectively. RNG k–ɛ model is recommended for the simulation of the flow in an unbaffled stirred tank with magnetic rod due to its computational effort.

scholarly journals Detached Eddy Simulation of Turbulent Flow in Stirred Tank Reactor

2015 ◽  
Vol 127 ◽  
pp. 87-94 ◽  
Author(s):  
Thiyam Tamphasana Devi ◽  
Bimlesh Kumar ◽  
Ajey Kumar Patel
Keyword(s):  
Turbulent Flow ◽  
Stirred Tank ◽  
Detached Eddy Simulation ◽  
Stirred Tank Reactor ◽  
Tank Reactor ◽  
Eddy Simulation

On the Investigation of Flow around the Square Cylinder Based on Different LES Models

2012 ◽  
Vol 594-597 ◽  
pp. 2676-2679
Author(s):  
Zhe Liu
Keyword(s):  
Flow Characteristics ◽  
Turbulence Models ◽  
Navier Stokes ◽  
Detached Eddy Simulation ◽  
Square Cylinder ◽  
Rans Model ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Reynolds Averaged Navier Stokes ◽  
Les Model

Although the conventional Reynolds-averaged Navier–Stokes (RANS) model has been widely applied in the industrial and engineering field, it is worthwhile to study whether these models are suitable to investigate the flow filed varying with the time. With the development of turbulence models, the unsteady Reynolds-averaged Navier–Stokes (URANS) model, detached eddy simulation (DES) and large eddy simulation (LES) compensate the disadvantage of RANS model. This paper mainly presents the theory of standard LES model, LES dynamic model and wall-adapting local eddy-viscosity (WALE) LES model. And the square cylinder is selected as the research target to study the flow characteristics around it at Reynolds number 13,000. The influence of different LES models on the flow field around the square cylinder is compared.

Numerical CFD simulation of a batch stirred tank reactor with stationary catalytic basket

2012 ◽  
Vol 207-208 ◽  
pp. 596-606 ◽  
Author(s):  
Vania Santos-Moreau ◽  
Lena Brunet-Errard ◽  
Matthieu Rolland
Keyword(s):  
Cfd Simulation ◽  
Stirred Tank ◽  
Stirred Tank Reactor ◽  
Tank Reactor

Evaluation of Performance and Code-to-Code Variation of a Dynamic Hybrid RANS/LES Model for Simulation of Backward-Facing Step Flow

2018 ◽  
Author(s):  
Olalekan O. Shobayo ◽  
D. Keith Walters
Keyword(s):  
Cfd Simulation ◽  
Turbulence Models ◽  
Navier Stokes ◽  
Test Case ◽  
Mean Flow ◽  
Backward Facing Step ◽  
Ansys Fluent ◽  
Eddy Simulation ◽  
Dynamic Hybrid ◽  
Les Model

Computational fluid dynamics (CFD) simulation results are presented for the canonical test case of flow over a backward facing step (BFS). The BFS case exhibits complex physics including turbulent separation, reattachment, and boundary layer restart. Results are obtained using two different turbulence models as representative examples of two classes of modeling: Reynolds-averaged Navier-Stokes (RANS) and hybrid RANS-LES (large-eddy simulation). The specific models used are k-ω SST and dynamic hybrid RANS-LES (DHRL). The objective of the study is to compare the performance of both turbulence models as implemented in three different flow solvers (Flow Psi, Loci-CHEM, and Ansys FLUENT) and using three different methods for numerical discretization of the convective terms in the governing equations. Results are compared to experimental data for validation purposes. Results show that both k-ω SST and DHRL models are capable of reproducing the mean flow physics with reasonable accuracy. The differences due to solver algorithm and convective discretization scheme are apparent for both models, but the DHRL model shows more sensitivity, as expected. Overall the results highlight the importance of considering all integrated aspects of a turbulent CFD simulation to ensure that an optimum combination of model and numerical method are employed.

Large-eddy simulation of the turbulent free-surface flow in an unbaffled stirred tank reactor

2010 ◽  
Vol 65 (15) ◽  
pp. 4307-4322 ◽  
Author(s):  
N. Lamarque ◽  
B. Zoppé ◽  
O. Lebaigue ◽  
Y. Dolias ◽  
M. Bertrand ◽  
...  
Keyword(s):  
Free Surface ◽  
Large Eddy Simulation ◽  
Free Surface Flow ◽  
Surface Flow ◽  
Stirred Tank ◽  
Stirred Tank Reactor ◽  
Tank Reactor ◽  
Eddy Simulation ◽  
Large Eddy

scholarly journals CFD Simulation of Air Flow Over an Object with Gable Roof, Revised with Y+ Approach

2016 ◽  
Vol 16 (2) ◽  
pp. 85-94
Author(s):  
Juraj Králik
Keyword(s):  
Cfd Simulation ◽  
Turbulence Models ◽  
External Pressure ◽  
Dynamics Simulation ◽  
Detached Eddy Simulation ◽  
Eddy Simulation ◽  
Fine Mesh ◽  
Gable Roof ◽  
Computer Fluid Dynamics ◽  
Polyhedral Mesh

Abstract Aim of this contribution is to provide insight view into analysis focused on obtaining external pressure coefficients on isolated two storey low-rise building with 15° elevation gable roof using Computer Fluid Dynamics simulation and these are compared to values that offering Eurocodes. Final Volume Model consisting of polyhedral mesh will be used for analysis with two different turbulence models. Mesh was created with respect to y+ parameter, where desired value was below one which leads us to fine mesh type. Secondary aim of this contribution is to compare performance of selected turbulence models. For this purpose were chosen Detached Eddy Simulation and Large Eddy Simulation which are part of the Scale Resolving Simulation turbulence models.

Detached Eddy Simulation of the Turbulent Flow in a Stirred Tank

2011 ◽  
Vol 236-238 ◽  
pp. 1487-1491 ◽  
Author(s):  
Feng Ling Yang ◽  
Shen Jie Zhou ◽  
Gui Chao Wang
Keyword(s):  
Kinetic Energy ◽  
Turbulent Flow ◽  
Computational Cost ◽  
Stirred Tank ◽  
Detached Eddy Simulation ◽  
Mean Velocity ◽  
Eddy Simulation ◽  
Energy Profiles ◽  
Les Model ◽  
Des Model

In the present work, detached eddy simulation (DES) of the turbulent flow in an unbaffled stirred tank agitated by a six-pitched-blade turbine was carried out. The sliding mesh (SM) approach was applied to simulate the rotation of the impeller. For comparison, the computations based on the large eddy simulation (LES) model and RANS equations closed with Reynolds stress model (RSM) were also performed. The instantaneous velocity fluctuations, mean velocity and turbulent kinetic energy profiles were analyzed and compared with the laser doppler velocimetry (LDV) results from literature. Results show that DES model can capture the unsteady turbulent flow characteristics accurately. The mean velocity and turbulent kinetic energy profiles by the DES model are in good agreements with the LES results and the LDV data. Besides, the computational cost of DES is only about 80% of LES. By contrast, the results obtained by RSM are not so good. It can be concluded that the DES model can produce as similarly good predictions as LES with less computational cost, and can work as an alternative of the LES model in predicting the hydrodynamics in the stirred tanks.

Evaluation of large Eddy simulation and Euler-Euler CFD models for solids flow dynamics in a stirred tank reactor

AIChE Journal ◽  
2008 ◽  
Vol 54 (3) ◽  
pp. 766-778 ◽  
Author(s):  
Debangshu Guha ◽  
P. A. Ramachandran ◽  
M. P. Dudukovic ◽  
J. J. Derksen
Keyword(s):  
Large Eddy Simulation ◽  
Flow Dynamics ◽  
Stirred Tank ◽  
Stirred Tank Reactor ◽  
Tank Reactor ◽  
Eddy Simulation ◽  
Cfd Models ◽  
Large Eddy

scholarly journals Numerical Modeling of Venturi Flume

Hydrology ◽  
2021 ◽  
Vol 8 (1) ◽  
pp. 27
Author(s):  
Mehdi Heyrani ◽  
Abdolmajid Mohammadian ◽  
Ioan Nistor ◽  
Omerul Faruk Dursun
Keyword(s):  
Experimental Data ◽  
Cross Sections ◽  
Water Surface ◽  
Turbulence Models ◽  
Detached Eddy Simulation ◽  
Measure Flow Rate ◽  
Physical Test ◽  
Eddy Simulation ◽  
Venturi Flume ◽  
Les Model

In order to measure flow rate in open channels, including irrigation channels, hydraulic structures are used with a relatively high degree of reliance. Venturi flumes are among the most common and efficient type, and they can measure discharge using only the water level at a specific point within the converging section and an empirical discharge relationship. There have been a limited number of attempts to simulate a venturi flume using computational fluid dynamics (CFD) tools to improve the accuracy of the readings and empirical formula. In this study, simulations on different flumes were carried out using a total of seven different models, including the standard k–ε, RNG k–ε, realizable k–ε, k–ω, and k–ω SST models. Furthermore, large-eddy simulation (LES) and detached eddy simulation (DES) were performed. Comparison of the simulated results with physical test data shows that among the turbulence models, the k–ε model provides the most accurate results, followed by the dynamic k LES model when compared to the physical experimental data. The overall margin of error was around 2–3%, meaning that the simulation model can be reliably used to estimate the discharge in the channel. In different cross-sections within the flume, the k–ε model provides the lowest percentage of error, i.e., 1.93%. This shows that the water surface data are well calculated by the model, as the water surface profiles also follow the same vertical curvilinear path as the experimental data.

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