Assessment of standard <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si382.gif" display="inline" overflow="scroll"><mml:mi>k</mml:mi><mml:mtext>–</mml:mtext><mml:mi>ε</mml:mi></mml:math>, RSM and LES turbulence models in a baffled stirred vessel agitated by various impeller designs

Murthy, B.N.; Joshi, Jyeshtharaj B.

doi:10.1016/j.ces.2008.06.019

Cited by 186 publications

(36 citation statements)

References 39 publications

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“…For the vessel filled with water, the flow was predicted by the standard k-e model, which is commonly applied for prediction of fluid flow in stirred vessels and can give satisfactory predictions of the mean characteristics of the turbulent flow [26][27][28]. For the vessel filled with glycerin, the flow was in the laminar regime and was simulated by the laminar model.…”

Section: Turbulence Modelingmentioning

confidence: 99%

Effect of Gravity on the Hydrodynamics in an Unbaffled Stirred Vessel

Yang

Zhou

2015

Chem Eng & Technol

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The hydrodynamics in an unbaffled stirred vessel were simulated in order to highlight the effect of gravity on pressure and velocity distributions. Two fluids with different viscosity were studied for the laminar and turbulent flow regimes, respectively. The simulation results were compared with experimental data from the literature. Results indicate that for the higher-viscosity fluid, gravity only affects static pressure and that the effects of gravity on velocity and dynamic pressure are negligible. For the lower-viscosity fluid, however, gravity imposes a pronounced impact on static pressure, dynamic pressure, velocity, and turbulent kinetic energy. These findings indicate that careful consideration is necessary for the role that gravity plays in the study of free-surface hydrodynamics in unbaffled stirred vessels.

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Section: Turbulence Modelingmentioning

confidence: 99%

Effect of Gravity on the Hydrodynamics in an Unbaffled Stirred Vessel

Yang

Zhou

2015

Chem Eng & Technol

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“…In order to obtain relatively accurate results with less computer memory and CPU time, the

k - ε

standard turbulence model, due to its fast convergence speed, robust performance and wide application in engineering [31,32], is chosen to simulate the turbulent flow here:

\frac{\partial (ρ k)}{\partial t} + \frac{\partial (ρ k u_{j})}{\partial x_{j}} = \frac{\partial}{\partial x_{j}} [false(μ + \frac{μ_{t}}{σ_{k}} false) \frac{\partial k}{\partial x_{j}}] + ρ (P_{k} - ε),

\frac{\partial (ρ ε)}{\partial t} + \frac{\partial (ρ ε u_{j})}{\partial x_{j}} = \frac{\partial}{\partial x_{j}} [false(μ + \frac{μ_{t}}{σ_{ε}} false) \frac{\partial ε}{\partial x_{j}}] + ρ \frac{ε}{k} (C_{1} P_{k} - C_{2} ε),

where ε denotes the dissipation rate of turbulent kinetic energy, and k denotes the fluid turbulent kinetic energy. Notice that the known constants used in this model are chosen as

σ_{k} = 1.0

σ_{ε} = 1.3

C_{1} = 1.44

and

C_{2} = 1.92

.…”

Section: Numerical Simulationsmentioning

confidence: 99%

Aerodynamic Drag Analysis of 3-DOF Flex-Gimbal GyroWheel System in the Sense of Ground Test

Huo

Feng

Liu

et al. 2016

Sensors

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GyroWheel is an innovative device that combines the actuating capabilities of a control moment gyro with the rate sensing capabilities of a tuned rotor gyro by using a spinning flex-gimbal system. However, in the process of the ground test, the existence of aerodynamic disturbance is inevitable, which hinders the improvement of the specification performance and control accuracy. A vacuum tank test is a possible candidate but is sometimes unrealistic due to the substantial increase in costs and complexity involved. In this paper, the aerodynamic drag problem with respect to the 3-DOF flex-gimbal GyroWheel system is investigated by simulation analysis and experimental verification. Concretely, the angular momentum envelope property of the spinning rotor system is studied and its integral dynamical model is deduced based on the physical configuration of the GyroWheel system with an appropriately defined coordinate system. In the sequel, the fluid numerical model is established and the model geometries are checked with FLUENT software. According to the diversity and time-varying properties of the rotor motions in three-dimensions, the airflow field around the GyroWheel rotor is analyzed by simulation with respect to its varying angular velocity and tilt angle. The IPC-based experimental platform is introduced, and the properties of aerodynamic drag in the ground test condition are obtained through comparing the simulation with experimental results.

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“…The k-ε model has also been compared to the RSTM (Reynolds Stress Turbulent Model) and LES (Large Eddy Simulation) in the work of B.N. Murthy et al [17]. They found that the standard k-ε model under predicted the turbulent kinetic energy profile in the impeller region and failed to simulate the mean flow associated with the strong swirl.…”

Section: Introductionmentioning

confidence: 99%

Effect of Impeller Design on Power Characteristics and Newtonian Fluids Mixing Efficiency in a Mechanically Agitated Vessel at Low Reynolds Numbers

2020

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The mixing process is a widespread phenomenon, which plays an essential role among a large number of industrial processes. The effectiveness of mixing depends on the state of mixed phases, temperature, viscosity and density of liquids, mutual solubility of mixed fluids, type of stirrer, and, what is the most critical property, the shape of the impeller. In the present research, the objective was to investigate the Newtonian fluids flow motion as well as all essential parameters for the mechanically agitated vessel with a new impeller type. The velocity field, the power number, and the pumping capacity values were determined using computer simulation and experimental measurements. The basis for the assessment of the intensity degree and the efficiency of mixing had to do with the analysis of the distribution of velocity vectors and the power number. An experimental and numerical study was carried out for various stirred process parameters and for fluids whose viscosity ranged from low to very high in order to determine optimal conditions for the mixing process.

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Assessment of standard k–ε, RSM and LES turbulence models in a baffled stirred vessel agitated by various impeller designs

Cited by 186 publications

References 39 publications

Effect of Gravity on the Hydrodynamics in an Unbaffled Stirred Vessel

Effect of Gravity on the Hydrodynamics in an Unbaffled Stirred Vessel

Aerodynamic Drag Analysis of 3-DOF Flex-Gimbal GyroWheel System in the Sense of Ground Test

Effect of Impeller Design on Power Characteristics and Newtonian Fluids Mixing Efficiency in a Mechanically Agitated Vessel at Low Reynolds Numbers

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