scholarly journals Enhanced Bauxite Recovery Using a Flotation Column Packed with Multilayers of Medium

Minerals ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 594 ◽  
Author(s):  
Pengyu Zhang ◽  
Wencai Zhang ◽  
Leming Ou ◽  
Yuteng Zhu ◽  
Zicheng Zhu
Keyword(s):  
Silicon Content ◽  
Cfd Simulation ◽  
Fluid Velocity ◽  
Flotation Column ◽  
Flotation Recovery ◽  
Content Ratio ◽  
Turbulent Characteristics ◽  
Computational Fluid Dynamics Cfd ◽  
Simulation Results ◽  
The Impact

An innovative self-designed medium was packed in a bench-scale flotation column to study its influence on the flotation recovery of bauxite. Computational fluid dynamics (CFD) simulation was conducted to reveal the impact of the packing medium on the turbulent characteristics of collection zone in the column. Simulation results show that multilayer packing of the medium divides the collection zone into small units having different turbulent intensities, which is more suitable for flotation separation. The packing medium decreases the turbulence kinetic energy (from 1.08 × 10−2 m2/s2 to 2.1 × 10−3 m2/s2), turbulence eddy dissipation (from 3.71 × 10−2 m2/s3 to 9.8 × 10−3 m2/s3) and axial fluid velocity of fluid in the column. With three layers of packing, the recovery of Al2O3 increased by 2.11% and the aluminum to silicon content ratio of the concentrate improved from 5.16 to 9.72.

scholarly journals Fine Bauxite Recovery Using a Plate-Packed Flotation Column

Metals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1184
Author(s):  
Pengyu Zhang ◽  
Saizhen Jin ◽  
Leming Ou ◽  
Wencai Zhang ◽  
Yuteng Zhu
Keyword(s):  
Cfd Simulation ◽  
Balance Model ◽  
Fine Grained ◽  
Flotation Column ◽  
Bubble Distribution ◽  
Mineral Particles ◽  
Flotation Columns ◽  
Computational Fluid Dynamics Cfd ◽  
Bauxite Ore ◽  
Simulation Results

In this investigation, the fine-grained bauxite ore flotation was conducted in a plate-packed flotation column. This paper evaluated the effects of packing-plates on recovering fine bauxite particles and revealed the fundamental mechanisms. Bubble coalescence and break-up behaviors in the packed and unpacked flotation columns were characterized by combining Computational Fluid Dynamics (CFD) and Population Balance Model (PBM) techniques. Flotation experiments showed that packing-plates in the collection zone of a column can improve bauxite flotation performance and increase the smaller bauxite particles recovery. Using packing-plates, the recovery of Al2O3 increased by 2.11%, and the grade of Al2O3 increased by 1.85%. The fraction of −20 μm mineral particles in concentrate increased from 47.31% to 54.79%. CFD simulation results indicated that the packing-plates optimized the bubble distribution characteristics and increased the proportion of microbubbles in the flotation column, which contributed to improving the capture probability of fine bauxite particles.

Effect of Buoyancy and Density Ratio on Heat Transfer in a Smooth Cooling Channel of a Gas Turbine Blade

2018 ◽  
Author(s):  
Mandana S. Saravani ◽  
Saman Beyhaghi ◽  
Ryoichi S. Amano
Keyword(s):  
Heat Transfer ◽  
Rotational Speed ◽  
Cfd Simulation ◽  
Density Ratio ◽  
Reynolds Numbers ◽  
Buoyancy Effect ◽  
Square Channel ◽  
First Case ◽  
Computational Fluid Dynamics Cfd ◽  
The Impact

The present work investigates the effects of buoyancy and density ratio on the thermal performance of a rotating two-pass square channel. The U-bend configuration with smooth walls is selected for this study. The channel has a square cross-section with a hydraulic diameter of 5.08 cm (2 inches). The lengths of the first and second passes are 514 mm and 460 mm, respectively. The turbulent flow enters the channel with Reynolds numbers of up to 34,000. The rotational speed varies from 0 to 600 rpm with the rotational numbers up to 0.75. For this study, two approaches are considered for tracking the buoyancy effect on heat transfer. In the first case, the density ratio is set constant, and the rotational speed is varied. In the second case, the density ratio is changed in the stationary case, and the effect of density ratio is discussed. The range of Buoyancy number along the channel is 0–6. The objective is to investigate the impact of Buoyancy forces on a broader range of rotation number (0–0.75) and Buoyancy number scales (0–6), and their combined effects on heat transfer coefficient for a channel with aspect ratio of 1:1. Several computational fluid dynamics (CFD) simulation are carried out for this study, and some of the results are validated against experimental data.

Optimal Hardware Placement in a Minitower Computer Enclosure System

2011 ◽  
Author(s):  
M. Alfaro Cano ◽  
A. Hernandez-Guerrero ◽  
C. Rubio Arana ◽  
Aristotel Popescu
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Cfd Simulation ◽  
Operating Temperature ◽  
Optimal Placement ◽  
Cfd Analysis ◽  
Computational Fluid Dynamics Cfd ◽  
Simulation Results ◽  
The Relationship ◽  
Key Questions

One of the requirements for existing personal computers, PCs, is that the hardware inside must maintain an operating temperature as low as possible. One way to achieve that is to place the hardware components at locations with enough airflow around it. However, the relationship between the airflow and temperature of the components is unknown before they are placed at specific locations inside a PC. In this work a Computational Fluid Dynamics (CFD) analysis is coupled to a Design of Experiment (DOE) methodology to answer typical minitower key questions: a) how do the possible positions of hardware components affect their temperature?, and b) is it possible to get an optimal placement for these hardware components using the data collected by the CFD simulation results? The DOE methodology is used to optimize the analysis for a very large number of possible configurations. The results help in identifying where the efforts need to be placed in order to optimize the positioning of the hardware components for similar configurations at the designing stage. Somehow the results show that general conclusions could be drawn, but that there are not specific rules that could be applied to every configuration.

Simulation on Flow Field and Temperature Field in Water Cooling Tuyere of Blast Furnace

2013 ◽  
Vol 753-755 ◽  
pp. 2709-2712 ◽  
Author(s):  
Ya Na Qie ◽  
Shu Hui Zhang ◽  
Qing Lv ◽  
Li Hong Zhang
Keyword(s):  
Temperature Field ◽  
Economic Benefit ◽  
Cfd Simulation ◽  
Water Pressure ◽  
High Yield ◽  
Maximum Temperature ◽  
Water Cooling ◽  
Direct Motion ◽  
Computational Fluid Dynamics Cfd ◽  
Simulation Results

Life span of water cooling tuyere is one of important factors of blast furnace’s direct motion and high yield. In order to improve the life of tuyere, the flow fleld and temperature field of tuyere were simulated by using computational fluid dynamics (CFD). Simulation results show that the maximum temperature appears at the front margin of tuyere outlet side. The highest temperature of tuyere reduces significantly with the increase of water pressure below 0.4MPa. When the water pressure exceeds 0.4Pa, the highest temperature reduces slowly. In consideration of economic benefit and cooling effect, the best point of inlet pressure is 0.4MPa or so.

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.

scholarly journals Optimization of Window Positions for Wind-Driven Natural Ventilation Performance

Energies ◽  
2020 ◽  
Vol 13 (10) ◽  
pp. 2464
Author(s):  
Nari Yoon ◽  
Mary Ann Piette ◽  
Jung Min Han ◽  
Wentao Wu ◽  
Ali Malkawi
Keyword(s):  
Architectural Design ◽  
Natural Ventilation ◽  
Cfd Simulation ◽  
Design Decision ◽  
Building Facades ◽  
Window Position ◽  
Computational Fluid Dynamics Cfd ◽  
Ventilation Performance ◽  
Energy Simulations ◽  
The Impact

This paper optimizes opening positions on building facades to maximize the natural ventilation’s potential for ventilation and cooling purposes. The paper demonstrates how to apply computational fluid dynamics (CFD) simulation results to architectural design processes, and how the CFD-driven decisions impact ventilation and cooling: (1) background: A CFD helps predict the natural ventilation’s potential, the integration of CFD results into design decision-making has not been actively practiced; (2) methods: Pressure data on building facades were obtained from CFD simulations and mapped into the 3D modeling environment, which were then used to identify optimal positions of two openings of a zone. The effect of the selected opening positions was validated with building energy simulations; (3) results: The cross-comparison study of different window positions based on different geographical locations quantified the impact on natural ventilation effectiveness; and (4) conclusions: The optimized window position was shown to be effective, and some optimal solutions contradicted the typical cross-ventilation strategy.

scholarly journals Performance Assessment of Bladeless Micro-Expanders Using 3D Numerical Simulation

2019 ◽  
Vol 113 ◽  
pp. 03016 ◽  
Author(s):  
Avinash Renuke ◽  
Alberto Traverso ◽  
Matteo Pascenti
Keyword(s):  
Shear Stress ◽  
Cfd Simulation ◽  
Numerical Data ◽  
Flow Density ◽  
Cfd Analysis ◽  
Mixing Zone ◽  
Sst Turbulence Model ◽  
Computational Fluid Dynamics Cfd ◽  
Simulation Results ◽  
First Time

This paper summarizes the development of fully 3D Computational Fluid Dynamics (CFD) analysis for bladeless air micro expander for 200 W and 3 kW rated power. Modelling of nozzle along with rotor is done using structured mesh. This analysis, for the first time, demonstrates the interaction between nozzle and rotor using compressible flow density-based solver. The Shear Stress Transport (SST) turbulence model is employed to resolve wall effects on the rotor and to determine the shear stress accurately. The results illustrate the flow field inside stator and rotor along with complicated mixing zone between stator and rotor. The comparison of rotor-stator CFD simulation results is done with experiments to preliminary validate the model. The losses in the turbine are discussed with the help of experimental and numerical data.

The Research of Temperature Fields in the Proximity of a Bundle of Heated Pipes Arranged Above Each Other

2017 ◽  
Vol 139 (8) ◽  
Author(s):  
Jozef Cernecky ◽  
Zuzana Brodnianska ◽  
Przemysław Błasiak ◽  
Jan Koniar
Keyword(s):  
Heat Transfer ◽  
Cfd Simulation ◽  
Temperature Fields ◽  
Horizontal Shift ◽  
Geometric Conditions ◽  
Interferometry Method ◽  
Computational Fluid Dynamics Cfd ◽  
Transfer Parameters ◽  
C 50 ◽  
The Impact

The paper deals with the research of temperature fields in the proximity of heated pipes arranged above each other in a natural air convection. The holographic interferometry method was used for the visualization of temperature fields. The experiments were made with pipes, diameter of 20 mm, length 200 mm, spacing two-dimensional (2D) at surface temperatures of 40 °C, 50 °C, and 60 °C, with the vertical arrangement of the pipes as well as with the horizontal shift of their centers by 1/4D and 1/2D (on a surface temperature of 50 °C). Temperature profiles were determined from the experimentally obtained images of temperature fields, and local parameters of heat transfer were calculated. Under the same marginal and geometric conditions, computational fluid dynamics (CFD) simulations of temperature fields were performed as well, while the results (temperature fields, local and mean parameters of heat transfer) were also calculated for various distances between the pipe centers (1D, 2D, and 3D). From the obtained experimental results and CFD simulation results, it is possible to observe the impact of the arrangement and spacing of pipes on heat transfer parameters. The achieved results imply the change in the spacing of the pipes has a greater impact on heat transfer parameters in the bundle of heated pipes located above each other than a moderate horizontal shift of their centers.

Impact Forces of Submarine Landslides on Free-Span Pipelines

2014 ◽  
Author(s):  
Jun Liu ◽  
Jianlong Tian
Keyword(s):  
Fluid Mechanics ◽  
Oil And Gas ◽  
Impact Angle ◽  
Submarine Landslides ◽  
Prediction Formula ◽  
Impact Forces ◽  
Computational Fluid Dynamics Cfd ◽  
Simulation Results ◽  
The Impact ◽  
Apparent Influence

Submarine landslides are perhaps the most significant geohazard on the deep water oil and gas developments, especially on the pipelines. The impacted forces of submarine landslides on pipelines are usually expressed in terms of drag factors within a fluid mechanics framework. The drag factors mainly depend on an equivalent Reynolds number for the non-Newtonian debris material. In this paper, Computational Fluid Dynamics (CFD) numerical analysis was employed to analyze the impact forces of submarine landslides on free span pipelines. In these numerical simulations, influences on impact forces of debris material composition, attack angles and velocity of debris flow were discussed in detail. Based on the simulation results we find that the impact angle also has apparent influence on normal drag factors, but has little influence on longitudinal drag factors. Prediction formula are improved to better estimate normal and axial impact forces on pipelines at any attack angle within the fluid mechanics framework.

Test and Simulation of the Effects of Surface Roughness on a Shrouded Centrifugal Impeller

2014 ◽  
Author(s):  
William T. Cousins ◽  
Lei Yu ◽  
Jacquelynn Garofano ◽  
Barbara Botros ◽  
Vishnu Sishtla ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Cfd Simulation ◽  
Centrifugal Impeller ◽  
Test Results ◽  
Cfd Simulations ◽  
Computational Fluid Dynamics Cfd ◽  
The Common ◽  
R Value ◽  
The Impact ◽  
Grain Roughness

Surface roughness is an important parameter in the operational efficiency and loss development of turbomachinery components. Many computational fluid dynamics (CFD) simulations are performed on turbomachinery, but often one of the common assumptions is that the surfaces are hydraulically smooth. In this work, examination of the surfaces of two cast impellers is performed and compared to machined impellers with smoother surfaces. Both impeller sets were run in a two-stage industrial chiller unit using R134a refrigerant. Test results are presented and the impact of surface roughness modeling on the design is reviewed. Also discussed is the theory of the impact of roughness on turbulent boundary layers. Details about providing the CFD simulation with the proper sand grain roughness is discussed when surface finish (R-value) in microinches (μin) is measured.

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