Numerical Investigation on the Stirred Reactor with Rushton Turbine

2014 ◽  
Vol 881-883 ◽  
pp. 1823-1826
Author(s):  
Li Dai ◽  
Li Bin Yang ◽  
Kai Liu
Keyword(s):  
Cfd Simulation ◽  
Numerical Results ◽  
Turbulent Model ◽  
Rushton Turbine ◽  
Design And Optimization ◽  
Flow Prediction ◽  
Stirred Reactor ◽  
Discretization Schemes ◽  
Flow Information ◽  
Computational Fluid Dynamics Cfd

Computational Fluid Dynamics (CFD) simulation is expected to give detailed flow information which is important for stirred reactor design and optimization, however accurate flow prediction remains a challenge for CFD application. In the present paper, influence of discretization scheme on the flow prediction in a stirred reactor with Rushton turbine was investigated. Standardk-εturbulent model and MRF model was adopted and numerical results obtained by using three different discretization schemes were compared. Results showed that the numerical results agreed well with data provided in literature. It is acceptable to use any discreticaiton method if aiming at a general flow field, while QUICK is recommended considering the more detailed flow information.

Experimental and theoretical analyses of two-dimensional flows upstream of broad-crested weirs

2008 ◽  
Vol 35 (9) ◽  
pp. 975-986 ◽  
Author(s):  
M. Salih Kirkgoz ◽  
M. Sami Akoz ◽  
A. Alper Oner
Keyword(s):  
Cfd Simulation ◽  
Turbulence Models ◽  
Free Surface Flows ◽  
Velocity Fields ◽  
Numerical Results ◽  
Cfd Modeling ◽  
Two Dimensional ◽  
The Finite Element Method ◽  
Image Velocimetry ◽  
Computational Fluid Dynamics Cfd

Using the particle image velocimetry (PIV) technique, the laboratory experiments are conducted to measure the velocity fields of two-dimensional turbulent free surface flows upstream of rectangular and triangular broad-crested weirs. The experimental flow cases are analyzed theoretically by a computational fluid dynamics (CFD) modeling in which the finite element method is used to solve the governing equations. In the CFD simulation, the volume of fluid (VOF) method is used to compute the free surfaces of the flows. Using the standard k–ε and standard k–ω turbulence models, the numerical results for the velocity fields and flow profiles are compared with the experimental results for validation purposes. The computed results using k–ω turbulence model on compressed mesh systems are found in good agreement with measured data. The flow cases are also analyzed theoretically using the potential flow (PF) approach, and the numerical results for the velocity fields are compared with measurements.

CFD Simulation of Solid Suspension in a Stirred Reactor Driven by a Dual Punched Rigid-Flexible Impeller

2018 ◽  
Vol 16 (5) ◽  
Author(s):  
Deyin Gu ◽  
Zuohua Liu ◽  
Facheng Qiu ◽  
Jun Li ◽  
Changyuan Tao ◽  
...  
Keyword(s):  
Reference Frames ◽  
Cfd Simulation ◽  
Energy Dissipation Rate ◽  
Solid Particles ◽  
Stirred Tank ◽  
Two Phase ◽  
Stirred Reactor ◽  
Solid Suspension ◽  
Computational Fluid Dynamics Cfd ◽  
Solid Liquid

Abstract Solid suspension characteristics were predicted by computational fluid dynamics (CFD) simulation in a stirred tank driven by a dual rigid-flexible impeller and a dual punched rigid-flexible impeller. An Eulerian-Eulerian approach, standard k-ε turbulence model, and multiple reference frames (MRF) technique were employed to simulate the solid-liquid two-phase flow, turbulent flow, and impeller rotation in the stirred tank, respectively. The CFD results showed that dual punched rigid-flexible impeller could increase the axial velocity and turbulent kinetic energy dissipation rate, and decrease the quantity of sediment solid particles compared with dual rigid-flexible impeller. Less impeller power was consumed by dual punched rigid-flexible impeller compared with dual rigid-flexible impeller at the same impeller speed. It was found that punched rigid-flexible impeller was more efficient in terms of solid suspension quality than dual rigid-flexible impeller at the same Pw. The simulated results for the axial solid concentration were in good agreement with the experimental data.

scholarly journals Turbulent Flows Inside Pipes Equipped With Novel Perforated V-Shaped Rectangular Winglet Turbulators: Numerical Simulations

2020 ◽  
Vol 142 (11) ◽  
Author(s):  
M. Erfanian Nakhchi ◽  
M. T. Rahmati
Keyword(s):  
Turbulent Flows ◽  
Cfd Simulation ◽  
Vortex Generators ◽  
Fluid Mixing ◽  
Turbulent Model ◽  
Recirculating Flow ◽  
The Core ◽  
Turbulent Characteristics ◽  
Efficiency Parameter ◽  
Computational Fluid Dynamics Cfd

Abstract In this study, computational simulations have been performed to investigate the turbulent characteristics and energy consumption through heat exchanger tubes equipped by new perforated V-shaped rectangular winglet (PVRW) turbulators. The effects of the holes intensity on the velocity and temperature contours are additionally investigated. The Reynolds number, hole diameter ratio, and the number of holes selected are in the range of 5000 ≤ Re ≤ 18,000, 0 ≤ DR ≤ 0.40, and 0 ≤ N ≤ 14, respectively. Renormalization group (RNG) k–ε turbulent model which is a finite volume solver is utilized for the computational fluid dynamics (CFD) simulation. It was noticed that the proposed perforated turbulators could considerably intensify the thermal performance compared to typical VRW inserts. It is found that the recirculating flow generated by the PVRW augments the fluid mixing and transfers the heat from the pipe walls to the core of the tube. The simulations illustrate that the amount of heat transfer enhances 25.2% reducing the DR from 0.4 to 0.13 at Re = 18,000 and N = 14. Also, using PVRW turbulators with N = 7 and DR = 0.26 augments the average Nusselt number around 354.3% compared to the circular pipe without inserts. The highest thermal efficiency parameter of η = 2.25 could be obtained at Re = 5000 for the heat exchangers fitted by vortex generators with N = 14 and DR = 0.26.

Virtual Reality Visualization of CFD Simulation for Iron/Steelmaking Processes

2010 ◽  
Author(s):  
Dong Fu ◽  
Bin Wu ◽  
Guoheng Chen ◽  
John Moreland ◽  
Fengguo Tian ◽  
...  
Keyword(s):  
Virtual Reality ◽  
Cfd Simulation ◽  
Flow Characteristics ◽  
Industrial Applications ◽  
Projection System ◽  
Design And Optimization ◽  
Virtual Engineering ◽  
Engineering Environment ◽  
Computational Fluid Dynamics Cfd ◽  
Save Energy

Computational Fluid Dynamics (CFD) has become a powerful simulation technology used in iron/steelmaking industrial applications for process design and optimization to save energy. In this paper, a Virtual Engineering (VE) application is presented that uses Virtual Reality (VR) to visualize CFD results in a tracked immersive projection system. The interactive Virtual Reality (VR) was specifically adapted for CFD post-processing to better understand CFD results and more efficiently communicate with non-CFD experts. The VE application has been utilized to make an assessment in terms of visualization and optimization for steelmaking furnaces. The immersive system makes it possible to gain a quick, intuitive understanding of the flow characteristics and distributions of pressure, temperature, and species properties in the industrial equipment. By introducing the virtual engineering environment, the value of CFD simulations has been greatly enhanced to allow engineers to gain much needed process insights for the design and optimization of industrial processes.

scholarly journals Effects of Uncertainty and Quasi-Chaotic Geometry on the Leakage of Brush Seals

2019 ◽  
Vol 141 (2) ◽  
Author(s):  
Alexander Fuchs ◽  
Oskar J. Haidn
Keyword(s):  
Turbulence Models ◽  
Numerical Data ◽  
Leakage Flow ◽  
Flow Prediction ◽  
Brush Seal ◽  
Discretization Schemes ◽  
Computational Fluid Dynamics Cfd ◽  
Brush Seals ◽  
Irregular Arrangement ◽  
Theoretical State

This article presents a brief review of the experimental and theoretical state of the art regarding the leakage flow prediction of brush seals. The authors model a computational fluid dynamics (CFD)-based approach for the leakage flow of brush seals. The brush seal is treated by modeling its real geometrical structure, namely numerous bristles in an array in transverse flow. The fluid domain is segregated into discrete volumes surrounding each bristle. Two different discretization schemes are chosen to study their influence on the leakage behavior. Furthermore, for each scheme multiple inter-bristle distances, pressure ratios and turbulence models are evaluated. In addition, the influence of irregular arrangement configurations, which forms a quasi-chaotic inner structure, is studied. The results gained are compared to other authors' experimental and numerical data.

Numerical Simulation for Under-Floor Air Distribution System With Swirl Diffusers

2006 ◽  
Vol 129 (4) ◽  
pp. 589-594 ◽  
Author(s):  
Xiuling Wang ◽  
Darrell W. Pepper
Keyword(s):  
Mesh Generation ◽  
Distribution System ◽  
Cfd Simulation ◽  
Las Vegas ◽  
Air Distribution ◽  
Turbulent Model ◽  
Building Technology ◽  
Computational Fluid Dynamics Cfd ◽  
Thermal Patterns ◽  
The University

A finite volume renormalization group (RNG) k-ε turbulent model was employed to simulate an under-floor air distribution (UFAD) system consisting of eight swirl diffusers. Mesh generation was conducted using PRO/E and GAMBIT. Computational fluid dynamics (CFD) results using FLUENT show both flow and thermal patterns for an instrumented laboratory room (Building Technology Laboratory-BTL) located at the University of Nevada Las Vegas. Simulation results are presented using symmetrical boundary settings for the BTL. Stratification heights and clear zones are discussed. The application of CFD simulation provides insightful analyses in UFAD design and placement.

CFD Simulation and Retrofit of Natural Ventilation in a Steel Workshop

2011 ◽  
Vol 383-390 ◽  
pp. 6608-6613 ◽  
Author(s):  
Ya Xin Su ◽  
Xin Wan
Keyword(s):  
Fluid Dynamics ◽  
Experimental Data ◽  
Natural Ventilation ◽  
Cfd Simulation ◽  
Turbulent Model ◽  
Steel Company ◽  
Radiation Model ◽  
Iron And Steel ◽  
Computational Fluid Dynamics Cfd ◽  
Cfd Method

Natural ventilation in an workshop of iron and steel company has been numerically simulated by computational fluid dynamics (CFD) method. Realizable k −ε turbulent model combined with a DO radiation model which took into account the radiation between the heat source and the wall was applied to carry out the simulation for a typical industrial workshop. Numerical results were verified by published experimental data of local temperature and further modification of the workshop structure was made based on numerical calculation to improve the natural ventilation effect further.

scholarly journals Computational fluid dynamics (CFD) simulation analysis on retinal gas cover rates using computational eye models

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Makoto Gozawa ◽  
Yoshihiro Takamura ◽  
Tomoe Aoki ◽  
Kentaro Iwasaki ◽  
Masaru Inatani
Keyword(s):  
Cfd Simulation ◽  
Simulation Analysis ◽  
Fluid Dynamic ◽  
Fluid Analysis ◽  
Intraocular Gas ◽  
Pars Plana ◽  
Computational Fluid Dynamics Cfd ◽  
Multiple Breaks ◽  
Gas Volume ◽  
Wall Wettability

AbstractWe investigated the change in the retinal gas cover rates due to intraocular gas volume and positions using computational eye models and demonstrated the appropriate position after pars plana vitrectomy (PPV) with gas tamponade for rhegmatogenous retinal detachments (RRDs). Computational fluid dynamic (CFD) software was used to calculate the retinal wall wettability of a computational pseudophakic eye models using fluid analysis. The model utilized different gas volumes from 10 to 90%, in increments of 10% to the vitreous cavity in the supine, sitting, lateral, prone with closed eyes, and prone positions. Then, the gas cover rates of the retina were measured in each quadrant. When breaks are limited to the inferior retina anterior to the equator or multiple breaks are observed in two or more quadrants anterior to the equator, supine position maintained 100% gas cover rates in all breaks for the longest duration compared with other positions. When breaks are limited to either superior, nasal, or temporal retina, sitting, lower temporal, and lower nasal position were maintained at 100% gas cover rates for the longest duration, respectively. Our results may contribute to better surgical outcomes of RRDs and a reduction in the duration of the postoperative prone position.

scholarly journals Numerical Investigation for the Resin Filling Behavior during Ultraviolet Nanoimprint Lithography of Subwavelength Moth-Eye Nanostructure

Coatings ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 799
Author(s):  
Yuanchi Cui ◽  
Xuewen Wang ◽  
Chengpeng Zhang ◽  
Jilai Wang ◽  
Zhenyu Shi
Keyword(s):  
Simulation Model ◽  
Nanoimprint Lithography ◽  
Cfd Simulation ◽  
Boundary Slip ◽  
Accurate Analysis ◽  
Inlet Velocity ◽  
Filling Height ◽  
Proposed Model ◽  
Good Consistency ◽  
Computational Fluid Dynamics Cfd

Accurate analysis of the resin filling process into the mold cavity is necessary for the high-precision fabrication of moth-eye nanostructure using the ultraviolet nanoimprint lithography (UV-NIL) technique. In this research, a computational fluid dynamics (CFD) simulation model was proposed to reveal resin filling behavior, in which the effect of boundary slip was considered. By comparison with the experimental results, a good consistency was found, indicating that the simulation model could be used to analyze the resin filling behavior. Based on the proposed model, the effects of process parameters on resin filling behavior were analyzed, including resin viscosity, inlet velocity and resin thickness. It was found that the inlet velocity showed a more significant effect on filling height than the resin viscosity and thickness. Besides, the effects of boundary conditions on resin filling behavior were investigated, and it was found the boundary slip had a significant influence on resin filling behavior, and excellent filling results were obtained with a larger slip velocity on the mold side. This research could provide guidance for a more comprehensive understanding of the resin filling behavior during UV-NIL of subwavelength moth-eye nanostructure.

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