scholarly journals Design and Investigation of a 3D-Printed Micro-Fluidized Bed

2021 ◽  
Vol 5 (3) ◽  
pp. 62
Author(s):  
Yi Zhang ◽  
Kheng-Lim Goh ◽  
Yuen-Ling Ng ◽  
Yvonne Chow ◽  
Vladimir Zivkovic
Keyword(s):  
Fluidized Bed ◽  
Volume Fraction ◽  
Liquid Velocity ◽  
Low Cost ◽  
Surface Friction ◽  
Solid Particles ◽  
Fungal Pellets ◽  
3D Printed ◽  
Bed Expansion ◽  
Bubble Regime

Micro-fluidized bed has aroused much attention due to its low-cost, intensified-process and fast-screening properties. In this paper, a micro-fluidized bed (15 × 15 mm in cross-section) was designed and fabricated with the use of the stereolithography printing technique, for the investigation of bubbles’ hydrodynamics and comparison of the solids (3D-printed particles VS fungal pellets) fluidization characteristics. In a liquid–gas system, bubble flow regime started from mono-dispersed homogeneous regime, followed by poly-dispersed homogeneous regime, transition bubble regime and heterogeneous bubble regime with increasing gas flowrates from 3.7 mL/min to 32.7 mL/min. The impacts from operating parameters such as gas flowrate, superficial liquid velocity and gas sparger size on bubble size, velocity and volume fraction have been summarized. In liquid–solid fluidization, different solid fluidization regimes for both particles bed and pellets bed were identified. From the bed expansion results, much higher Umf of 7.8 mm/s from pellets fluidization was observed compared that of 2.3 mm/s in particles fluidization, because the hyphal structures of fungal pellets increased surface friction but also tended to agglomerate. The similar R–Z exponent n (5.7 and 5.5 for pellets and particles, respectively) between pellets and particles was explained by the same solid diameter, but much higher Ut of 436 µm/s in particles bed than that of 196 µm/s in pellets bed is a consequence of the higher density of solid particles. This paper gives insights on the development of MFB and its potential in solid processing.

The effect of ring baffles on the hydrodynamics of a gas—solid bubbling fluidized bed using computational fluid dynamics

2009 ◽  
Vol 223 (10) ◽  
pp. 2281-2289 ◽  
Author(s):  
S H Hosseini ◽  
R Rahimi ◽  
M Zivdar ◽  
A Samimi
Keyword(s):  
Fluidized Bed ◽  
Volume Fraction ◽  
Fluid Model ◽  
Expansion Ratio ◽  
Bubbling Fluidized Bed ◽  
Gas Volume Fraction ◽  
Two Fluid Model ◽  
Particle Velocities ◽  
Bed Expansion ◽  
Gas Volume

An Eulerian—Eulerian two-fluid model (TFM) integrating the kinetic theory for emulsion phase was used to simulate gas—solid fluidized beds. Validation of the model was investigated based on hydrodynamic parameters such as bed expansion ratio, H/ H0, gas volume fraction profile, bubble behaviour, and motion of the particles. A good agreement was found between numerical results and experimental values. The model was used to study a bubbling fluidized bed (BFB) including the ring baffles. Predicted results show that the ring baffles have an important role in the flow pattern of the bed. Baffles increase the bed expansion height and particle velocities at axial locations on the top of the highest baffle as well as uniform distribution of gas volume fraction between the baffles area. In spite of increasing the dead zones in the bed, ring baffles cause the improvement of mixing and heat transfer in the bed. The present study provides a useful basis for further works on the effect of baffles in BFBs.

Prediction of Solid Recirculation Rate and Solid Volume Fraction in an Internally Circulating Fluidized Bed

2015 ◽  
Vol 12 (04) ◽  
pp. 1540005 ◽  
Author(s):  
Ravi Gujjula ◽  
Narasimha Mangadoddy
Keyword(s):  
Experimental Data ◽  
Fluidized Bed ◽  
Circulating Fluidized Bed ◽  
Volume Fraction ◽  
Draft Tube ◽  
Numerical Study ◽  
Solid Particles ◽  
Granular Temperature ◽  
Solids Concentration ◽  
Drag Laws

This paper presents a numerical study of gas and solid flow in an internally circulating fluidized bed (ICFB). Two-fluid Eulerian model with kinetic theory of granular flow option for solid phase stress closure and various drag laws were used to predict the hydrodynamic behavior of ICFB. 2D and 3D geometries were used to run the simulations. The 2D simulation results by various drag laws show that the Arastoopour and Gibilaro drag models able to predict the fluidization dynamics in terms of flow patterns, void fractions and axial velocity fields close to the experimental data. The effect of superficial gas velocity, presence of draft tube on solid hold-up distribution, solid circulation pattern, and variations in gas bypassing fraction for the 3D ICFB are investigated. The mechanism governing the solid circulation and solids concentration in an ICFB has been explained based on gas and solid dynamics obtained from the simulations. Predicted total granular temperature distributions in the draft tube and annular zones qualitatively agree with experimental data. The total granular temperature tends to increase with increasing solids concentration in the dilute region (ε < 0.1) and decreases with an increase of solids concentration in the dense region (ε > 0.1). In the dense zone, the decreasing trend in the granular temperature is mainly due to the reduction of the mean free path of the solid particles.

Numerical Analysis on the Dynamic Behaviour of Fluidized Bed Reactor

2015 ◽  
Vol 813-814 ◽  
pp. 718-722
Author(s):  
P.M. Suhaile ◽  
S. Rupesh ◽  
C. Muraleedharan ◽  
P. Arun
Keyword(s):  
Fluid Dynamics ◽  
Fluidized Bed ◽  
Volume Fraction ◽  
Solid Phase ◽  
Fluid Model ◽  
Turbulence Models ◽  
Fluidized Bed Reactor ◽  
Two Fluid Model ◽  
Bed Expansion ◽  
Phase Transport

A gas-solid multiphase flow is simulated using CFD to investigate the fluid dynamics of a fluidized bed reactor. The simulation is based on Euler-Euler two fluid model where Kinetic Theory of Granular Flow is used for predicting the solid phase transport properties. The simulation procedure is validated by reproducing and comparing hydrodynamic parameters with those available in the literature. The effect of different turbulence models on bed fluid dynamics is analyzed and k-ε RNG per-phase model is found to have better prediction accuracy compared to other models. The minimum fluidization velocity, granular temperature, bed expansion, particle velocity and volume fraction are determined by the model.

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.

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 investigation of slugging behavior in a gas-solids fluidized bed

2017 ◽  
Vol 23 (4) ◽  
pp. 529-536 ◽  
Author(s):  
Yanjun Guan ◽  
Xiuying Yao ◽  
Guiying Wu ◽  
Kai Zhang
Keyword(s):  
Fluidized Bed ◽  
Volume Fraction ◽  
Fluid Model ◽  
Predictive Ability ◽  
Momentum Equation ◽  
Expansion Ratio ◽  
Viscous Force ◽  
Spectrum Density ◽  
Two Fluid Model ◽  
Bed Expansion

The hydrodynamics of a slugging fluidized bed is investigated numerically by using a two-fluid model suggested by Brandani and Zhang [22]. Numerical simulations are carried out in the platform of a commercial software package, CFX 4.4, by adding user-defined subroutines. The bed expansion ratio, the pressure drop fluctuation and its power spectrum density at the equipment scale and the solids volume fraction distributions at the grid scale are predicted to explore the slugging fluidization characteristics for Geldart group D particles. By comparing with the experimental data in the literature, the numerical model is found to have better predictive ability when the viscous force term is considered in the gas phase momentum equation.

scholarly journals Continuous Fiber-Reinforced Aramid/PETG 3D-Printed Composites with High Fiber Loading through Fused Filament Fabrication

Polymers ◽  
2022 ◽  
Vol 14 (2) ◽  
pp. 298
Author(s):  
Sander Rijckaert ◽  
Lode Daelemans ◽  
Ludwig Cardon ◽  
Matthieu Boone ◽  
Wim Van Paepegem ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Composite Materials ◽  
Fiber Volume Fraction ◽  
Volume Fraction ◽  
Low Cost ◽  
Fiber Direction ◽  
Continuous Fiber ◽  
Fiber Volume ◽  
Fiber Loading ◽  
3D Printed

Recent development in the field of additive manufacturing, also known as three-dimensional (3D) printing, has allowed for the incorporation of continuous fiber reinforcement into 3D-printed polymer parts. These fiber reinforcements allow for the improvement of the mechanical properties, but compared to traditionally produced composite materials, the fiber volume fraction often remains low. This study aims to evaluate the in-nozzle impregnation of continuous aramid fiber reinforcement with glycol-modified polyethylene terephthalate (PETG) using a modified, low-cost, tabletop 3D printer. We analyze how dimensional printing parameters such as layer height and line width affect the fiber volume fraction and fiber dispersion in printed composites. By varying these parameters, unidirectional specimens are printed that have an inner structure going from an array-like to a continuous layered-like structure with fiber loading between 20 and 45 vol%. The inner structure was analyzed by optical microscopy and Computed Tomography (µCT), achieving new insights into the structural composition of printed composites. The printed composites show good fiber alignment and the tensile modulus in the fiber direction increased from 2.2 GPa (non-reinforced) to 33 GPa (45 vol%), while the flexural modulus in the fiber direction increased from 1.6 GPa (non-reinforced) to 27 GPa (45 vol%). The continuous 3D reinforced specimens have quality and properties in the range of traditional composite materials produced by hand lay-up techniques, far exceeding the performance of typical bulk 3D-printed polymers. Hence, this technique has potential for the low-cost additive manufacturing of small, intricate parts with substantial mechanical performance, or parts of which only a small number is needed.

scholarly journals Dry particle generation with a 3D printed fluidized bed generator

2017 ◽  
Author(s):  
Michael Roesch ◽  
Carolin Roesch ◽  
Daniel J. Cziczo
Keyword(s):  
Fluidized Bed ◽  
Particle Number ◽  
Mineral Dust ◽  
Low Cost ◽  
Dust Sample ◽  
Field Studies ◽  
Particle Generation ◽  
Total Particle ◽  
3D Printed ◽  
Micrometer Size

Abstract. Here we describe the design and testing of a compact fluidized bed aerosol generator named PRIZE (PRinted fluidIZed bed gEnerator) manufactured using stereolithography (SLA) printing. Dispersing small quantities of powdered materials – due either to rarity or expense – is challenging due to a lack of small, low-cost dry aerosol generators. With this as motivation, we designed and built a generator that uses a mineral dust or other dry powder sample mixed with bronze beads that sit atop a porous screen. A particle free airflow is introduced, dispersing the sample as airborne particles. Particle number concentration and size distributions were measured during different stages of the assembling process to show that the SLA 3D printed generator did not generate particles until the mineral dust sample was introduced. Time-series measurements with Arizona Test Dust (ATD) showed stable total particle number concentrations of 10–150 cm−3, depending on the sample mass, from the sub- to super-micrometer size range. PRIZE is simple to assemble, easy to clean, inexpensive and deployable for laboratory and field studies that require dry particle generation.

Fluidization of fungal pellets in a 3D-printed micro-fluidized bed

2021 ◽  
Vol 236 ◽  
pp. 116466
Author(s):  
Yi Zhang ◽  
Yuen Ling Ng ◽  
Kheng-Lim Goh ◽  
Yvonne Chow ◽  
Steven Wang ◽  
...  
Keyword(s):  
Fluidized Bed ◽  
Fungal Pellets ◽  
3D Printed

Expanded Bed Adsorption: An Option For Energy Savings In Multiple Proteins Purification

2012 ◽  
pp. 31-34
Author(s):  
Kavitha T C ◽  
B.S.V.S.R. Krishna
Keyword(s):  
Fluidized Bed ◽  
Energy Savings ◽  
Packed Bed ◽  
Operating Conditions ◽  
Solid Particles ◽  
Expanded Bed Adsorption ◽  
Expanded Bed ◽  
Hydrodynamic Behaviour ◽  
Multiple Particles ◽  
Bed Expansion

Expanded Bed Adsorption enables the protein recovery directly from cultivations of microorganisms or cells and preparations of disrupted cells, without the need for prior removal of suspended solids. The performance ofan expanded bed is comparable to a packed bed owing to reduced mixing of the adsorbent particles, clogging/plugging of solid particles in the column, while fluidized bed requires more velocity which may hinder the adsorption equilibrium. However,optimal operating conditions are more restricted than in a packed bed/fluidized bed due to the dependence of bed expansion on the sizeand density of the adsorbent particles as well as the viscosity and density of the feedstock. These difficulties can beovercomes in expanded-bed chromatography. In this work the steady state hydrodynamic behaviour of expanded beds studied experimentally.The present study focused on hydrodynamics of multiple particles separation and subsequently can be applied to the multiple proteins separation in a single expanded bed.

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