scholarly journals Effect of Wall Heat Transfer on the Fluidization Process

2021 ◽  
Vol 39 (2) ◽  
pp. 615-620
Author(s):  
Huda Ridha‏ ◽  
Mohammed Ghalib Al-Azawy
Keyword(s):  
Fluidized Bed ◽  
Solid Phase ◽  
Solid Particles ◽  
Superficial Velocity ◽  
Working Fluid ◽  
Aluminum Particles ◽  
Ansys Fluent ◽  
Computational Fluid Dynamics Cfd ◽  
Phase Temperature ◽  
Fluidization Process

The fluidized bed and the fluidization process and characteristics were studied in this paper numerically using Computational Fluid Dynamics (CFD) Ansys Fluent 15.0. Constant temperature was applied to both sides of the two-dimensional fluidized bed geometry. The superficial velocity of the working fluid ranged amid (0.08 – 0.5 m/s) and the initial height of the solid particles changed amid (0.05, 0.1, 0.2 m). Aluminum particles and water was used as working materials within the fluidized bed. The model used for the investigations was validated using Ngoh and Lim research results. The results showed that the fluidization head increases as the water inlet superficial velocity increases. As well as when the water inlet superficial velocity increases, the average solid phase temperature increases.

Predictive Erosion Modeling in an ESP Pump

2014 ◽  
Author(s):  
Sahand Pirouzpanah ◽  
Gerald L. Morrison
Keyword(s):  
Solid Phase ◽  
Phase Particle ◽  
Flow Behavior ◽  
Primary Flow ◽  
Ansys Fluent ◽  
Electrical Submersible Pumps ◽  
Computational Fluid Dynamics Cfd ◽  
Operating Lifetime ◽  
Two Stages ◽  
Particle Laden Flow

Electrical Submersible Pumps (ESPs) are widely used in upstream oil production. The presence of a low concentration solid phase, particle-laden flow, in the production fluid may cause severe damage in the internal sections of the pump which reduces its operating lifetime. To better understand the ESP pump’s endurance, an ESP-WJE1000, manufactured by Baker Hughes Company was studied numerically to determine the pump’s flow behavior at its best efficiency point. Computational Fluid Dynamics (CFD) analysis was conducted on two stages of the pump’s primary flow path employing Eulerian-Granular scheme in ANSYS-Fluent. The key parameters affecting the erosion phenomena within the pump such as turbulence kinetic energy, local sand concentration and near wall relative sand velocity were identified. The predictive erosion model applicable to pumps was developed by correlating the erosion key parameters with available experimental results.

scholarly journals A CFD Study of Industrial Double-Cyclone in HDPE Drying Process

2018 ◽  
Vol 2 (1) ◽  
Author(s):  
S.A. Razavi Alavi ◽  
E. Nemati Lay ◽  
Z.S. Alizadeh Makhmali
Keyword(s):  
Pressure Drop ◽  
Fluidized Bed ◽  
Solid Particles ◽  
Ansys Fluent ◽  
Lagrangian Framework ◽  
Inlet Flow Rate ◽  
Drying Behavior ◽  
Fluent Software ◽  
Fluidized Bed Drying

Double-cyclone in fluidized bed drying is an important equipment which reflects the conditions of drying in HDPE slurry process. Cyclone is an important unite of fluidized bed drying in order to move the solid particles outward to its wall. Therefore, flow pattern created in fluidized bed will affect industrial cyclones installed in dryer for dust removing. Pressure drop of the cyclones is an effective parameter represents the drying behavior. Substantially, geometry of cyclone, inlet flow rate of gas, density and particle size distribution (PSD) can affect the pressure drop value. Fluidized bed hydrodynamic regime is very complex and must be understood to improve fluidized bed operations through theoretical, industrial and CFD study of double-cyclone. Pressure drop is introduced as parameter related to the cyclone efficiency can be calculated with ANSYS Fluent software in the Eulerian-Lagrangian framework with RNG k-ɛ turbulence model used as a mathematical method. Proper pressure drop concluded from industrial experiments and CFD calculation shows good fluidization of HDPE particles in the bed of nitrogen and powder  to reach the best fluidized bed situation and suitable quality of HDPE powdery product.

Experiment and Numerical Simulation on Slugging Fluidization of Large Particles in Gas-Solid Fluidized Bed

2014 ◽  
Vol 881-883 ◽  
pp. 689-697
Author(s):  
Hui Yang ◽  
Dong Yu Wan ◽  
Chang Qing Cao
Keyword(s):  
Fluidized Bed ◽  
Expansion Ratio ◽  
Solid Particles ◽  
Momentum Exchange ◽  
Cold Model ◽  
State Behavior ◽  
Large Particles ◽  
Computational Fluid Dynamics Cfd ◽  
Bed Expansion

The hydrodynamics of a two-dimensional gas-solid fluidized bed with 0.03 m diameter and 0.3 m height were studied experimentally and computationally. The slugging fluidization of large particles was experimentally investigated and simulated using the Fluent 6.3 computational fluid dynamics (CFD) package. By a series of cold-model test, characterization of gas-solid fluidization with large particles was studied. These results can be used to research slugging characteristics. A multifluid Eulerian model incorporating the kinetic theory for solid particles was applied to simulate the unsteady-state behavior and momentum exchange coefficients were calculated by using the Syamlal-OBrien drag functions. These results of the transfer of fluidization state, maximum bed expansion ratio and pressure fluctuation were systemically simulated in a gas-solid fluidized bed. The modeling predictions compared reasonably well with experimental data and qualitative slugging regime. The simulation results can better predict the slugging fluidization characterization of large particles.

Hydrodynamic and Thermal Modeling of Circulating Fluidized Bed Solar Receivers

2016 ◽  
Author(s):  
Serhat Bilyaz ◽  
Ilker Tari
Keyword(s):  
Heat Transfer ◽  
Fluidized Bed ◽  
Circulating Fluidized Bed ◽  
Solid Phase ◽  
Energy System ◽  
Solid Particles ◽  
Solar Thermal Energy ◽  
Void Fractions ◽  
Planar Cells ◽  
Solar Receiver

The riser tube solar receiver of a circulating fluidized bed solid particle absorption solar thermal energy system was numerically modeled for analyzing hydrodynamic and heat transfer behaviors of the solid particles in the riser. Hydrodynamics of the model is validated by comparing radial distribution of void fractions with an experimental study. For the heat transfer from the opaque walls of the receiver that is heated to high temperatures by the solar rays concentrated by the heliostat field, a simple fractional model is used in which radiative transfer is neglected and total heat flux is distributed to phases according to the instantaneous volume fractions at the boundary cells. MFIX: Multiphase Flow with Interphase eXchanges code of NETL is used with a 2.5D Eulerian-Eulerian computational model for transient simulations. The 2.5D grid is a combination of planar cells and cylindrical cells with the determined optimum fraction of planar cells of 0.15. For the solar receiver riser, transient and time averaged results of void fraction and gas and solid phase temperature distributions were numerically obtained and analyzed.

Solid to Gas Temperature Gradient in a Microwave Fluidized Bed

2011 ◽  
Vol 9 (1) ◽  
Author(s):  
Zeljko Pajkic ◽  
Achim Schmidt ◽  
Thorsten Gerdes ◽  
Monika Willert-Porada
Keyword(s):  
Fluidized Bed ◽  
Room Temperature ◽  
Materials Science ◽  
Solid Phase ◽  
Reaction Engineering ◽  
Gas Temperature ◽  
Science And Engineering ◽  
Materials Science And Engineering ◽  
Phase Temperature ◽  
Two Phases

Convective heat transfer from solid to gas was investigated in a microwave heated fluidized bed and compared to an identical conventionally heated bed. Fluidizing gas was fed at room temperature and heated in contact with the bed solid phase. Solid phase temperature was varied in range of 300-600°C. Temperature difference of the two phases and heat loss by gas stream were measured in both heating types and discussed regarding chemical reaction engineering and energy efficiency. Advantages of microwave heating in such systems were elaborated with an outlook to perspective applications of the process in field of materials science and engineering.

Numerical Research Of Influence Of Disperse Composition On Characteristics Of Combustion Of Coal-Fired Circulating Fluidized Bed

2016 ◽  
Vol 11 (3) ◽  
pp. 53-61
Author(s):  
Vladimir Salomatov ◽  
Andrey Gil ◽  
Aleksandr Starchenko ◽  
Roman Arkhipov
Keyword(s):  
Fluidized Bed ◽  
Circulating Fluidized Bed ◽  
Solid Phase ◽  
Radiation Heat Transfer ◽  
Solid Particles ◽  
Fluidised Bed ◽  
Two Phase ◽  
Chemical Reaction Kinetics ◽  
Characteristic Features ◽  
Ignition And Combustion

The peculiarity of mathematical modeling of the circulating fluidized bed (CFB) is that the solid phase (fuel and ash particles) is always a polydispersed medium. The paper constructed a mathematical model of gas dynamics, heat and mass transfer and combustion in the furnace volume of CFB steam generator with a highly concentrated content of the dispersed phase in relation to the investigation of processes in aerothermochemical CFB furnace. Taking into account: the turbulent structure of the two-phase flow, radiation heat transfer in a dusty environment, the chemical reaction kinetics of ignition and combustion, the effects of the power and thermal interactions between the particles and the particles with the wall. A model of such an environment has been chosen phenomenological model of interpenetrating continua Rahmatulina HA. The characteristic features of CFB technology are: firstly organized circulation of solid particles; Second, the repeated return unburned coarse fractions in the fluidised bed. As a result, during the low-temperature burn-in CFB increased almost two orders of magnitude compared with torch mode, allowing you to burn the most difficult fuels in the energy sector. Numerical analysis of data showed that the best results on the effects of polydisperse composition for fuel combustion characteristics in CFB process provides a particle size distribution in which a small fraction predominates.

scholarly journals Computational Fluid Dynamic Simulation and Validation Bed Expansion of Three-Phase Co-Current Fluidized Bed

2018 ◽  
Vol 26 (6) ◽  
pp. 1-15
Author(s):  
Zainab Abdulameer Joodi ◽  
Zaidoon M. Shakoor ◽  
Amer A. Abdul- Rahmana
Keyword(s):  
Fluidized Bed ◽  
Computational Fluid Dynamic ◽  
Liquid Velocity ◽  
Solid Phase ◽  
Fluid Dynamic ◽  
Computational Fluid Dynamic Simulation ◽  
Ansys Fluent ◽  
Three Phase ◽  
Inner Diameter ◽  
Bed Expansion

The bed expansion of gas-liquid-solid co-current fluidized bed is studied in the present work. Experimental work is carried out using Perspex column having 0.092 m inner diameter, 2 m height. Kerosene and air are used as continuous and dispersed phases, respectively. Glass beads having 0.0038 m diameter and 2247 kg/m3 density and catalyst particles having 0.0025 m diameter and   2070 kg /m3 density, which were taken from the kerosene hydrotreating reactor that is located in Al-Daura Refinery, are used as the solid phase. The Computational fluid dynamic CFD results of dynamic characteristics were obtained based on simulation using commercial CFD codes and ANSYS FLUENT 16.0 have been used for validation, by comparing the simulation and experimental results. Eulerian approach for flow of granular multiphase is utilized to predict the performance of the three-phase co-current fluidized bed. The results are indicated that the height of the expanded bed is having a strong function of liquid velocity, which increases as the liquid velocity increases too.

scholarly journals CFD-based numerical simulation of cyclone separator for separating stigmas from petals of saffron

2020 ◽  
Author(s):  
Javad Nemati ◽  
Babak Beheshti ◽  
Ali Mohammad Borghei
Keyword(s):  
Separation Efficiency ◽  
Solid Phase ◽  
Equations Of Motion ◽  
Fluid Phase ◽  
Reynolds Stress Model ◽  
Continuous Phase ◽  
Solid Particles ◽  
Inlet Section ◽  
Ansys Fluent ◽  
Discrete Phase

This study numerically modeled the flow of a fluid (air) and solid particles (saffron flower) inside a cyclone using the finite volume method (FVM) in ANSYS Fluent. The continuous phase was simulated under steady state conditions, as the initial condition, using the Reynolds Stress Model (RSM) for turbulence at three constant inlet air velocities of 1.5 m/s, 2.5 m/s, and 3.5 m/s over the inlet section. One-way coupling was assumed to govern all numerical analyses. The fluid phase and particles were treated as the continuous medium (within a Eulerian framework) and discrete phase (within a Lagrangian framework), respectively. The equations governing the gas phase included the compressible Navier–Stokes and the conservation of mass. The discrete phase equations included the equations of motion for three different particles including petals, stigmas, and anthers. According to the numerical results, the cyclone separation efficiency was calculated, and the static pressure and velocity contours were plotted. The results showed the capability of the CFD-based simulation for an accurate demonstration of the behavior of the fluid–solid phase. Accordingly, it can be used to predict the efficiency of stigma separation from petals of saffron using airflow in the cyclone. According to the results, the highest cyclonic separation efficiency of 89% was achieved at an inlet air velocity of 3.5 m/s, which was very close to the experimental data.

Solid-phase temperature in the combustion of carbon under fluidized-bed conditions

1978 ◽  
Vol 35 (1) ◽  
pp. 846-848
Author(s):  
A. A. Belyaev ◽  
G. N. Delyagin ◽  
V. G. Slutskii
Keyword(s):  
Fluidized Bed ◽  
Solid Phase ◽  
Phase Temperature

scholarly journals Experimental and CFD Simulations of the Aerosol Flow in the Air Ventilating the Underground Excavation in Terms of SARS-CoV-2 Transmission

Energies ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4743
Author(s):  
Tomasz Janoszek ◽  
Zbigniew Lubosik ◽  
Lucjan Świerczek ◽  
Andrzej Walentek ◽  
Jerzy Jaroszewicz
Keyword(s):  
Numerical Calculations ◽  
Mining Institute ◽  
Ventilation Network ◽  
Underground Excavation ◽  
In Situ Tests ◽  
Ansys Fluent ◽  
Aerosol Emission ◽  
Ansys Cfx ◽  
Computational Fluid Dynamics Cfd

The paper presents the results of experimental and model tests of transport of dispersed fluid droplets forming a cloud of aerosol in a stream of air ventilating a selected section of the underground excavation. The excavation selected for testing is part of the ventilation network of the Experimental Mine Barbara of the Central Mining Institute. For given environmental conditions, such as temperature, pressure, relative humidity, and velocity of air, the distribution of aerosol droplet changes in the mixture of air and water vapor along the excavation at a distance was measured at 10 m, 25 m, and 50 m from the source of its emission. The source of aerosol emission in the excavation space was a water nozzle that was located 25 m from the inlet (inlet) of the excavation. The obtained results of in situ tests were related to the results of numerical calculations using computational fluid dynamics (CFD). Numerical calculations were performed using Ansys-Fluent and Ansys-CFX software. The dimensions and geometry of the excavation under investigation are presented. The authors describe the adopted assumptions and conditions for the numerical model and discuss the results of the numerical solution.

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