Numerical Simulation of Gas Flow in a Square Cyclone Separator With Double Inlets

2007 ◽  
Author(s):  
Bin Xiong ◽  
Xiaofeng Lu ◽  
R. S. Amano
Keyword(s):  
Pressure Drop ◽  
Flow Field ◽  
Gas Flow ◽  
Numerical Study ◽  
Reynolds Stress Model ◽  
Cyclone Separator ◽  
Stress Model ◽  
Inlet Velocity ◽  
Vortex Finder ◽  
Flow Changes

This paper presents a numerical study of gas flow in a square cyclone separator with a double inlet. The turbulence of gas flow is computed by the use of the Reynolds stress model. The distribution of the flow field and pressure drop under different constructional details, which include changes of the shape, size and arrangement of the vortex finder are obtained. The computed results in the distributions of pressure in different sections are verified by comparison with those measured. We found that the center of the flow field is nearly on the geometric center of the cyclone. The flow fields show a feature of Rankine eddy, i.e., a strongly swirling region in the central part and a pseudo-free eddy region of weak swirling intensity near the cyclone wall. Local vortex exists at the corners where the flow changes their direction sharply, but it is less chaotic than in the general square cyclone with a single inlet. The flow field away from the outlet of the vortex finder is different from the Rankine eddy. The pressure-drop increases rapidly with the increase of the inlet velocity, and the pressure-drop increases with the decrease of the diameter of vortex finder and the increase of length of the vortex finder. The calculat ed results of this paper provide some guidance for the optimization of the square cyclone separator structure.

Investigation on Flow Field of Cyclone Separator Used in Circulating Fluidized Bed Boiler

2013 ◽  
Vol 807-809 ◽  
pp. 1551-1554
Author(s):  
Bing Guang Gao ◽  
Hai Xia Li ◽  
An Chao Zhang ◽  
Jun Song ◽  
Hao Lu ◽  
...  
Keyword(s):  
Flow Field ◽  
Fluidized Bed ◽  
Vortex Structure ◽  
Circulating Fluidized Bed ◽  
Swirling Flow ◽  
Reynolds Stress Model ◽  
Cyclone Separator ◽  
Stress Model ◽  
Fluent Software ◽  
Simulation Results

The Reynolds stress model (RSM) provided by FLUENT software was applied to study flow field of a cyclone separator used in some circulating fluidized bed. The pressure distribution and velocity distribution was analyzed. The simulation results reveal the strong swirling flow and vortex structure in cyclone separator.

Numerical Simulation of Flow Field and Separation Efficiency of Inclined Cut-In Double-Inlet Cyclone

2012 ◽  
Vol 184-185 ◽  
pp. 341-347
Author(s):  
Cai Jin Wu ◽  
Zheng Fei Ma ◽  
Yong Yang
Keyword(s):  
Numerical Simulation ◽  
Pressure Drop ◽  
Flow Field ◽  
Axial Velocity ◽  
Separation Efficiency ◽  
Tangential Velocity ◽  
Reynolds Stress Model ◽  
Stress Model ◽  
Three Dimension ◽  
Inclined Angle

The three-dimension flow field and the separation efficiency of the inclined cut-in double-inlet cyclone were simulated numerically with Reynolds Stress Model (RSM). Numerical results show that the flow field nonsymmetry is improved in the inclined cut-in double-inlet cyclone and the swirl in the flow field was decreased greatly compared to that in the single-inlet cyclone. With the increase of inclined angle, both the tangential velocity and the axial velocity first increase and then decrease, reaching a peak at inclined 12 ° angle and at inclined 10 ° angle, respectively. The pressure drop in the inclined cut-in double-inlet cyclone increases first and then decreases with the increase of inclined angle, reaching a maximum far lower than that in the single-inlet cyclone, while the change of the radial velocity is not obvious. The separation efficiency of the inclined cut-in double-inlet cyclone could be effectively improved and the optimum inclined angle is 10 °.

Numerical Study of Methane and Air Combustion Inside Heat-Recirculating Combustors

2013 ◽  
Author(s):  
Yanxia Li ◽  
Zhongliang Liu ◽  
Yan Wang ◽  
Jiaming Liu
Keyword(s):  
Gas Flow ◽  
Numerical Study ◽  
Convection Heat Transfer ◽  
Central Area ◽  
Small Scale ◽  
Inlet Velocity ◽  
Strong Convection ◽  
Simulation Results ◽  
Lean Fuel ◽  
Set Up

A numerical model on methane/air combustion inside a small Swiss-roll combustor was set up to investigate the flame position of small-scale combustion. The simulation results show that the combustion flame could be maintained in the central area of the combustor only when the speed and equivalence ratio are all within a narrow and specific range. For high inlet velocity, the combustion could be sustained stably even with a very lean fuel and the flame always stayed at the first corner of reactant channel because of the strong convection heat transfer and preheating. For low inlet velocity, small amounts of fuel could combust stably in the central area of the combustor, because heat was appropriately transferred from the gas to the inlet mixture. Whereas, for the low premixed gas flow, only in certain conditions (Φ = 0.8 ～ 1.2 when ν0 = 1.0m/s, Φ = 1.0 when ν0 = 0.5m/s) the small-scale combustion could be maintained.

scholarly journals Study of GLR and Inlet Velocity on Hydrocyclone for Fracturing Flow-Back Fluids

2019 ◽  
Vol 2019 ◽  
pp. 1-12
Author(s):  
Bing Liu ◽  
Huajian Wang ◽  
Luncao Li ◽  
Zhenjiang Zhao ◽  
Liping Xu ◽  
...  
Keyword(s):  
Particle Size ◽  
Separation Efficiency ◽  
Tangential Velocity ◽  
Reynolds Stress Model ◽  
Optimum Range ◽  
Inlet Velocity ◽  
Split Ratio ◽  
Vortex Finder ◽  
Computational Fluid Dynamics Cfd ◽  
Solid Liquid

In this work, based on the Reynolds stress model (RSM) of the computational fluid dynamics (CFD) software Fluent and experimental method, the velocity field, pressure characteristics, split ratio, and separation efficiency of the hydrocyclone are analyzed under different gas-liquid ratios (GLRs). For the inlet velocity, the lower limit is ascertained by the flow field stability, the upper limit is largely determined by the energy consumption, and the optimum range is 4 m/s to 10 m/s. Within the optimum range, the peak value of tangential velocity increases while the GLR increases, whereas the pressure and pressure drop decrease. With the increase in the GLR, the axial velocity decreases, and the locus of zero vertical velocity shifts inward. The increase in the GLR causes more gas to collect at the vortex finder, which hinders the discharge of the solid-liquid mixture from the overflow, and the larger the GLR, the faster the decrease in the split ratio. The separation efficiency of particles with a particle size of 15 μm is increased by 6.75%, and the separation efficiency of particles with a particle size of 30 μm is increased by 0.57%. Meanwhile, the separation efficiency is increased by 2.43%, and the cut size d50 is reduced as the GLR increases.

Experimental and numerical study of vortex gripper with a diversion body

2011 ◽  
Vol 226 (6) ◽  
pp. 1526-1534 ◽  
Author(s):  
Q Wu ◽  
Q Ye ◽  
G X Meng
Keyword(s):  
Fluid Dynamics ◽  
Numerical Simulation ◽  
Computational Fluid Dynamics ◽  
Swirling Flow ◽  
Numerical Study ◽  
Reynolds Stress Model ◽  
Stress Model ◽  
Lifting Force ◽  
Handling Device ◽  
Simulation Results

This article introduces a new vortex gripper with a diversion body. Vortex gripper, as a pneumatic non-contact handling device, can generate lifting force to hold a workpiece without any contact. In order to predict the characteristics of this new vortex gripper, including pressure distribution on the upper surface of the workpiece, lifting force, supporting stiffness, and flowrate, a computational fluid dynamics study has been carried out. In the vortex cup, air swirling flow is a complex turbulent one; so Reynolds stress model (RSM) was used to describe internal air swirling flow. In addition, an experiment was carried out to study the characteristics of the vortex gripper. When compared with the experimental results, the reliability of numerical simulation results by RSM was verified. The vortex gripper with a diversion body could generate greater lifting force when compared with those designed by Xin et al. with the same air consumption. Therefore, the efficiency of the vortex gripper is improved.

Numerical study of turbulent round jet in a uniform counterflow using a second order Reynolds Stress Model

2015 ◽  
Vol 9 (4) ◽  
pp. 482-495 ◽  
Author(s):  
Amani Amamou ◽  
Sabra Habli ◽  
Nejla Mahjoub Saïd ◽  
Philippe Bournot ◽  
Georges Le Palec
Keyword(s):  
Reynolds Stress ◽  
Numerical Study ◽  
Reynolds Stress Model ◽  
Second Order ◽  
Stress Model ◽  
Round Jet

Reynolds Stress Model in the Prediction of Confined Turbulent Swirling Flows

2006 ◽  
Vol 128 (6) ◽  
pp. 1377-1382 ◽  
Author(s):  
Ali M. Jawarneh ◽  
Georgios H. Vatistas
Keyword(s):  
Experimental Data ◽  
Pressure Drop ◽  
Reynolds Stress ◽  
Tangential Velocity ◽  
Radial Pressure ◽  
Reynolds Stress Model ◽  
Swirling Flows ◽  
Stress Model ◽  
Swirl Number ◽  
Pressure Profiles

Strongly swirling vortex chamber flows are examined experimentally and numerically using the Reynolds stress model (RSM). The predictions are compared against the experimental data in terms of the pressure drop across the chamber, the axial and tangential velocity components, and the radial pressure profiles. The overall agreement between the measurements and the predictions is reasonable. The predictions provided by the numerical model show clearly the forced and free vortex modes of the tangential velocity profile. The reverse flow (or back flow) inside the core and near the outlet, known from experiments, is captured by the numerical simulations. The swirl number has been found to have a measurable impact on the flow features. The vortex core size is shown to contract with the swirl number which leads to higher pressure drop, higher peak tangential velocity, and deeper radial pressure profiles near the axis of rotation. The adequate agreement between the experimental data and the simulations using RSM turbulence model provides a valid tool to study further these industrially important swirling flows.

scholarly journals Analysis of Separated Flows Inside an Annular Compressor Cascade Using a Low-Re-Number k-ϵ and an Algebraic Reynolds-Stress-Model

1997 ◽  
Author(s):  
Jürgen R. Lücke ◽  
Heinz E. Gallus
Keyword(s):  
Flow Field ◽  
Reynolds Stress ◽  
Three Dimensional ◽  
Separated Flow ◽  
Reynolds Stress Model ◽  
Stress Model ◽  
Mean Flow ◽  
Compressor Cascade ◽  
Production Term ◽  
Algebraic Reynolds Stress Model

The flow field inside an annular compressor cascade is numerically investigated. The mean flow features are complex three-dimensional zones of turbulent separation at hub and shroud at high inflow angles. The flow field is investigated with an implicit three-dimensional Navier-Stokes code. To predict turbulent effects the flow solver includes two different variants of a Low-Re-number k-ϵ-model and an algebraic Reynolds-stress-model. Using the Low-Re-number model the structure of the regions of separated flow are fairly well predicted. However, intensity and size of these zones are too small compared with the experimental data. Better results are produced using the anisotropic algebraic Reynolds-stress-model combined with a stagnation point modification of the turbulent production term. Stucture and intensity of the vortex systems are simulated in more detail. Static pressure distributions and loss contours are in a very good agreement with the experiments.

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