CFD Studies on Velocity Distribution of Air in a Swirling Fluidized Bed

2012 ◽  
Vol 468-471 ◽  
pp. 25-29 ◽  
Author(s):  
Mohd Faizal ◽  
Md Seri Suzairin ◽  
Mohd Al-Hafiz ◽  
Vijay Raj Raghavan
Keyword(s):  
Velocity Distribution ◽  
Radial Velocity ◽  
Fluidized Bed ◽  
Axial Velocity ◽  
Turbine Blades ◽  
Tangential Velocity ◽  
Industrial Applications ◽  
Air Velocity ◽  
High Efficient ◽  
Computational Fluid Dynamics Cfd

This paper presents computational fluid dynamics (CFD) studies to characterize air velocity distribution for various bed configurations in a swirling fluidized bed (SFB). Unlike conventional fluidized beds, a SFB provides radial mixing which is desirable is fluidization. Three velocities components were observed, the tangential velocity, radial velocity and axial velocity. These velocities were created as a result of using annular blade type distributor which mimics the turbine blades. In actual industrial applications, the axial velocity will create fluidization while the tangential velocity provides swirling effect. The presence of radial velocity can be explained as a consequence of centrifugal force generated by the swirling gas. Understanding these velocity distributions will enable optimization of the annular blade distributor design towards a high efficient fluidized bed system.

scholarly journals A Numerical Study of Chemical Reaction in a Nanofluid Flow Due to Rotating Disk in the Presence of Magnetic Field

2021 ◽  
Author(s):  
Muhammad Ramzan ◽  
Poom Kumam ◽  
Kottakkaran Sooppy Nisar ◽  
Ilyas Khan ◽  
Wasim Jamshed
Keyword(s):  
Differential Equation ◽  
Radial Velocity ◽  
Chemical Reaction ◽  
Axial Velocity ◽  
Numerical Study ◽  
Tangential Velocity ◽  
Rotating Disk ◽  
Partial Differential ◽  
Suction Parameter ◽  
Matlab Programming

Abstract In this paper, a numerical study of MHD steady flow due to the rotating disk with chemical reaction was explored. Effect of different parameters such as Schmidt number, chemical reaction parameter, Prandtl number, Suction parameter, heat absorption/generation parameter, Nano-particle concentration, Reynold number, Magnetic parameter, skin friction, shear stress, temperature distribution, Nusselt number, mass transfer rate, radial velocity, axial velocity, and tangential velocity was analyzed and discussed. For the simplification of non-linear partial differential equations (PDEs) into the nonlinear ordinary differential equation (ODEs), the method of Similarity transformation was employed, and the resulting partial differential equation was solved by using finite difference method through MATLAB programming. This work's remarkable finding is that with the expansion of nanoparticle concentration radial velocity, tangential velocity and temperature of the fluid was enhanced but reverse reaction for axial velocity. Furthermore, the present results are found to be in excellent agreement with previously published work.

scholarly journals Study on Flow Velocity during Wheeled Capsule Hydraulic Transportation in a Horizontal Pipe

Water ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 1181
Author(s):  
Yongye Li ◽  
Yuan Gao ◽  
Xihuan Sun ◽  
Xuelan Zhang
Keyword(s):  
Velocity Distribution ◽  
Radial Velocity ◽  
Flow Velocity ◽  
Axial Velocity ◽  
Structural Parameters ◽  
Polar Axis ◽  
Low Carbon ◽  
Horizontal Pipe ◽  
Annular Gap ◽  
Gap Flow

As a clean, low-carbon, and green hydraulic transportation technology, wheeled capsule pipeline hydraulic transportation is a transportation mode conducive to the sustainable development of the social economy. Based on the method of a physical model experiment and hydraulic theory, the flow velocity characteristics in the pipeline when the wheeled capsule with a length–diameter ratio of 2.5 and 2.14, respectively, was transported in the straight pipe section with an inner diameter of 100 mm were studied in this paper. The results show that in the process of transporting materials, the flow velocity distribution of the cross section near the upstream and downstream section of the capsule was basically the same, and the axial velocity was smaller in the middle of the pipe and larger near the inner wall of the pipe. The radial velocity distribution was more thinly spread near the pipe wall and denser near the center of the pipe. The circumferential flow velocity was distributed in the vicinity of the support body of the wheeled capsule. For any annular gap section around the wheeled capsule, the radial velocity of annular gap flow was very small, and the average radial velocity of annular gap flow was about 1/30 of the average axial velocity of annular gap flow and about 0.7 of the average circumferential velocity of annular gap flow. The axial, circumferential, and radial flow velocities on the same radius measuring ring changed with the polar axis in a wave pattern of alternating peaks and troughs. These results can provide the theoretical basis for optimizing structural parameters of the wheeled capsule.

A CFD Study of Gas-Solid Flow in Cyclones With a Tangential Single Inlet and a Direct Asymmetrical Spiral Inlet

2009 ◽  
Author(s):  
Bin Xiong ◽  
R. S. Amano ◽  
Xiaofeng Lu ◽  
Yingfeng Ji
Keyword(s):  
Pressure Drop ◽  
Velocity Distribution ◽  
Gas Flow ◽  
Collection Efficiency ◽  
Tangential Velocity ◽  
Reynolds Stress Model ◽  
Lagrangian Model ◽  
Solid Flow ◽  
Computational Fluid Dynamics Cfd ◽  
Particle Paths

This work presents a computational fluid dynamics (CFD) calculation of gas-solid flow in cyclones with a conventional tangential single inlet (CTSI) and a direct symmetrical spiral inlet (DSSI) which was developed by Zhao et al [1]. The Reynolds stress model (RSM) has been employed to predict the gas flow field and particle paths are calculated with the stochastic Lagrangian model. The calculated grade collection efficiency and pressure drop have reasonable agreement with the experimental data. All results indicate that the DSSI has effect on significantly increasing collection efficiency with insignificantly increasing pressure drop. Compared with the CTSI cyclone, the DSSI cyclone has higher collection efficiency due to larger tangential velocity distribution, less short re-circuiting flow and shorter distance for particles to move to the wall. But the larger tangential velocity distribution lead to a little higher pressure drop of the cyclone with DSSI.

Fluid Field Analysis for Cyclone Separator Used on Grain Cleaning

2012 ◽  
Vol 605-607 ◽  
pp. 1369-1371
Author(s):  
Ling Xin Geng ◽  
Li Jian Zhang ◽  
Qing Xiang Shi
Keyword(s):  
Radial Velocity ◽  
Axial Velocity ◽  
Tangential Velocity ◽  
Laser Doppler ◽  
Field Analysis ◽  
Laser Doppler Velocimeter ◽  
Structure Parameters ◽  
Cyclone Separator ◽  
Gas Velocity ◽  
Fluid Field

Gas velocity in cyclone separator is measured by testing with laser Doppler velocimeter in this paper. The measuring results indicates that tangential velocity, axial velocity, radial velocity of air distribute following some certain rules, reasonable selected structure parameters can improve separating efficiency

Numeric Investigation of an Axi-Symmetric Turbulent Jet

2014 ◽  
Author(s):  
Mohammad A. Hossain ◽  
Sarzina Hossain
Keyword(s):  
Experimental Data ◽  
Flow Field ◽  
Velocity Distribution ◽  
Radial Velocity ◽  
Axial Velocity ◽  
Turbulent Jet ◽  
Field Analysis ◽  
Turbulent Dissipation ◽  
Round Jet ◽  
Research Areas

This work is focused on a numerical investigation of a turbulent axi-symmetric round jet in order to incorporate the knowledge of turbulence. Flow field analysis of a turbulent jet is one of the major research areas in recent years as turbulent jet dictates the interaction between fluid and other physical phenomena. Heat transfer, natural convection, frame propagation all depend on the behavior of turbulent jet. The mass and momentum transfer phenomena governs the flow field of the jet. A two dimensional pressure based Navier-stock solver is used to resolve the flow parameter of a turbulent round jet. Around One hundred twenty five thousand quadratic mesh elements are used for the simulation. A Mesh independency test has been done before resolving results. Characteristic flow parameters such as mean axial velocity, mean radial velocity distribution, turbulent kinetic energy, turbulent intensity, the turbulent dissipation rate are determined and presented. Similarity solution for mean axial velocity distribution and mean radial velocity distribution at different axial location are calculated and compared with experimental data. The result shows good agreement with experimental data.

Velocity Distribution for the Flow of the Second-order Fluid with Variable Coefficients in Concentric Annulus with Isometric Ring Slots on the Inner Cylinder

2011 ◽  
Vol 233-235 ◽  
pp. 2875-2880
Author(s):  
Hai Qing Cui ◽  
Jun He ◽  
Xing Liang Song
Keyword(s):  
Velocity Distribution ◽  
Radial Velocity ◽  
Axial Velocity ◽  
Variable Coefficients ◽  
Second Order ◽  
Slot Width ◽  
Governing Equations ◽  
Concentric Annulus ◽  
Resultant Velocity ◽  
Cylindrical Coordinate

The governing equations of flow of the second-order fluid with variable coefficients through concentric annuli with isometric ring slots on the inner cylinder under the cylindrical coordinate system were established. The governing equations were numerically solved by the finite difference method, the influence of slot width, slot depth, slot interval and slot number on velocity distribution is analyzed. The results show that slot width and slot depth is related with radial velocity, axial velocity and resultant velocity, slot interval is related with radial velocity, which is little related with axial velocity and resultant velocity, slot number is little related with radial velocity, axial velocity and resultant velocity.

Effect of Produced Liquid Viscosity on Flow Characteristics and Separating Property of Downhole Hydrocyclone Desander

2014 ◽  
Vol 933 ◽  
pp. 250-254 ◽  
Author(s):  
Yue Juan Yan ◽  
Zun Ce Wang ◽  
Yan Xu Shang ◽  
Sen Li ◽  
Yan Xu
Keyword(s):  
Numerical Simulation ◽  
Pressure Drop ◽  
Radial Velocity ◽  
Axial Velocity ◽  
Separation Efficiency ◽  
Tangential Velocity ◽  
Flow Characteristics ◽  
Liquid Viscosity ◽  
Separating Property ◽  
Viscosity Changes

A new style single outlet downhole hydrocyclone desander with spiral deflectors was designed according to the working characters of downhole desander, which combined hydrocyclone separation and sediment separation. Numerical simulation was conducted to analysis effect of produced liquid viscosity on flow characteristics and separating property. The results show that the tangential velocity of hydrocyclone desander decreases rapidly and the axial velocity and radial velocity of hydrocyclone desander changes slightly when the produced liquid viscosity changes in the range of 1.5mPa·s ~ 30mPa·s. Separation efficiency drops sharply and pressure drop decreases slightly with the increasing of produced liquid viscosity.

scholarly journals Kinematics of Disk Stars in the Solar Neighbourhood

1998 ◽  
Vol 11 (1) ◽  
pp. 574-574
Author(s):  
A.E. Gómez ◽  
S. Grenier ◽  
S. Udry ◽  
M. Haywood ◽  
V. Sabas ◽  
...  
Keyword(s):  
Dispersion Relation ◽  
Radial Velocity ◽  
Velocity Dispersion ◽  
Tangential Velocity ◽  
Thin Disk ◽  
The Other ◽  
Proper Motions ◽  
Velocity Data ◽  
Kinematic Data ◽  
Radial Velocity Data

Using Hipparcos parallaxes and proper motions together with radial velocity data and individual ages estimated from isochones, the velocity ellipsoid has been determined as a function of age. On the basis of the available kinematic data two different samples were considered: a first one (7789 stars) for which only tangential velocities were calculated and a second one containing 3104 stars with available U, V and W velocity components and total velocities ≤ 65 km.s-1. The main conclusions are: -Mixing is not complete at about 0.8-1 Gyr. -The shape of the velocity ellipsoid changes with time getting rounder from σu/σv/σ-w = 1/0.63/0.42 ± 0.04 at about 1 Gyr to1/0.7/0.62 ±0.04 at 4-5 Gyr. -The age-velocity-dispersion relation (from the sample with kinematical selection) rises to a maximum, thereafter remaining roughly constant; there is no dynamically significant evolution of the disk after about 4-5 Gyr. -Among the stars with solar metallicities and log(age) > 9.8 two groups are identified: one has typical thin disk characteristics, the other is older than 10 Gyr and lags the LSR at about 40 km.s-1 . -The variation of the tangential velocity with age(without selection on the tangential velocity) shows a discontinuity at about 10 Gyr, which may be attributed to stars typically of the thick disk populations for ages > 10 Gyr.

Numerical Approaches for Modeling Gas–Solid Fluidized Bed Reactors: Comparison of Models and Application to Different Technical Problems

2019 ◽  
Vol 141 (7) ◽  
Author(s):  
Peter Ostermeier ◽  
Annelies Vandersickel ◽  
Stephan Gleis ◽  
Hartmut Spliethoff
Keyword(s):  
Calcium Carbonate ◽  
Size Distribution ◽  
Fluidized Bed ◽  
Fluid Model ◽  
Industrial Applications ◽  
Small Scale ◽  
Fluidized Bed Reactors ◽  
Discrete Phase Model ◽  
Technical Problems ◽  
Numerical Approaches

Gas–solid fluidized bed reactors play an important role in many industrial applications. Nevertheless, there is a lack of knowledge of the processes occurring inside the bed, which impedes proper design and upscaling. In this work, numerical approaches in the Eulerian and the Lagrangian framework are compared and applied in order to investigate internal fluidized bed phenomena. The considered system uses steam/air/nitrogen as fluidization gas, entering the three-dimensional geometry through a Tuyere nozzle distributor, and calcium oxide/corundum/calcium carbonate as solid bed material. In the two-fluid model (TFM) and the multifluid model (MFM), both gas and powder are modeled as Eulerian phases. The size distribution of the particles is approximated by one or more granular phases with corresponding mean diameters and a sphericity factor accounting for their nonspherical shape. The solid–solid and fluid–solid interactions are considered by incorporating the kinetic theory of granular flow (KTGF) and a drag model, which is modified by the aforementioned sphericity factor. The dense discrete phase model (DDPM) can be interpreted as a hybrid model, where the interactions are also modeled using the KTGF; however, the particles are clustered to parcels and tracked in a Lagrangian way, resulting in a more accurate and computational affordable resolution of the size distribution. In the computational fluid dynamics–discrete element method (CFD–DEM) approach, particle collisions are calculated using the DEM. Thereby, more detailed interparticulate phenomena (e.g., cohesion) can be assessed. The three approaches (TFM, DDPM, CFD–DEM) are evaluated in terms of grid- and time-independency as well as computational demand. The TFM and CFD–DEM models show qualitative accordance and are therefore applied for further investigations. The MFM (as a variation of the TFM) is applied in order to simulate hydrodynamics and heat transfer to immersed objects in a small-scale experimental test rig because the MFM can handle the required small computational cells. Corundum is used as a nearly monodisperse powder, being more suitable for Eulerian models, and air is used as fluidization gas. Simulation results are compared to experimental data in order to validate the approach. The CFD–DEM model is applied in order to predict mixing behavior and cohesion effects of a polydisperse calcium carbonate powder in a larger scale energy storage reactor.

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