Design optimization of a fluidized bed with a novel air chamber using the CFD-Taguchi method

2021 ◽  
pp. 095440622110293
Author(s):  
Fei Wang ◽  
Hao Yan ◽  
Yishan Zeng ◽  
Wei Xu ◽  
Haozhou Zang ◽  
...  
Keyword(s):  
Taguchi Method ◽  
Fluidized Bed ◽  
Gas Flow ◽  
Interaction Mechanism ◽  
Splitter Plate ◽  
Geometrical Parameters ◽  
The Novel ◽  
Residual Rate ◽  
Air Chamber ◽  
Level 1

The gas–solid fluidized bed is the key structure of industrial fluidization, and it is widely used in fields such as chemical reactors and industrial material conveying. To study the uniformity of velocity distribution ( Vu) in a fluidized bed and clarify the interaction mechanism between the geometric structure of the air chamber and the gas flow, in this paper, 16 novel chamber structures for powder unloading were designed based on the Taguchi method. Computational fluid dynamics was used to simulate the different chamber schemes, and the effects of various geometric factors on the response were analyzed based on the Taguchi method. The effect of the novel optimization model for powder unloading was verified by tests. The results show that the optimal combination of geometrical parameters is air chamber capacity ( V) at level 4, separation ratio ( K) at level 1 and clearance of splitter plate ( δ) at level 1, and δ has the greatest effect on the Vu1 and Vu2 in the fluidized bed. With the increase in δ and K, the velocity of the airflow away from the inlet side increases, and the area of the vortex near the splitter plate increases. Compared with the baseline model, the fluidized bed with the novel air chamber can effectively reduce the residual rate of powder unloading.

Design of a novel flat-cloth airway in powder tank based on Taguchi optimization

2021 ◽  
pp. 095440622110108
Author(s):  
Fei Wang ◽  
Hao Yan ◽  
Yishan Zeng ◽  
Wei Xu ◽  
Haozhou Zang ◽  
...  
Keyword(s):  
Fluidized Bed ◽  
Interaction Mechanism ◽  
Optimal Combination ◽  
Geometrical Parameters ◽  
Arc Length ◽  
Signal To Noise ◽  
Taguchi Optimization ◽  
Rank 2 ◽  
Material Transportation ◽  
H 51

The fluidized bed is a key structure in the field of material transportation and is widely used in special automobile and construction powder transportation. A novel flat-cloth airway structure for powder unloading was proposed based on the traditional fluidized bed in this study. To analyze the uniformity of the velocity distribution ( Vu) in the fluidized bed and clarify the interaction mechanism between the geometric structure of the fluidized bed and airflow, 16 geometric structures of the fluidized bed for powder unloading were designed. Different schemes of the fluidized bed were numerically calculated by computational fluid dynamics, and the advantages of each scheme were analyzed by the Taguchi method and multiple regression. The length of the annular vortexes at the inlet of the airways becomes shorter than before as the number of airways increases. Airway height ( H), airway angle ( θ) and airway arc length ( L) exert statistically significant effects. Specifically, H (Delta = 6.45 rank =1) has the greatest effect on signal-to-noise ratios, L (Delta = 2.60 rank =2) has the second greatest effect and θ (Delta = 1.82 rank =3) has the least effect. The optimal combination of geometrical parameters of the fluidized bed is 15 mm H, 51° θ and 200 mm L.

Gas flow in a pressurized fluidized-bed combustor

1988 ◽  
Vol 56 (3) ◽  
pp. 157-163 ◽  
Author(s):  
J. Thýn ◽  
Z. Kolar ◽  
W. Martens ◽  
A. Korving
Keyword(s):  
Fluidized Bed ◽  
Gas Flow ◽  
Fluidized Bed Combustor

The Pyrocarbon Deposition Techniques of Mechanical Heart Valve Prostheses

2011 ◽  
Vol 464 ◽  
pp. 749-752 ◽  
Author(s):  
Jian Hui Zhang ◽  
Xin Chen
Keyword(s):  
Fluidized Bed ◽  
Heart Valve ◽  
Gas Flow ◽  
Mechanical Heart Valve ◽  
Carbon Matrix ◽  
Artificial Heart Valve ◽  
Bed Temperature ◽  
Wide Range ◽  
Isotropic Carbon ◽  
Deposition Conditions

The structure and property of pyrocarbon varies widely with different deposition conditions. The isotropic carbon which can only been deposited in the bed of fluidized particles is very important in biomedical fields, for instance, it is often used as the coating of artificial heart valve components. The deposition of isotropic pyrocarbon containing silicon is experimented in fluidized bed over a wide range of deposition conditions. The results show that bed temperature influences strongly average coating rate, coating density, silicon content and coating micro-hardness. Propane concentration has a much effect on coating density, carbon matrix density and isotropic characteristics. Total gas flow rate and inlet dimension of fluidized bed affect the formation of fluidized bed.

scholarly journals Multiple-q noncollinear magnetism in an itinerant hexagonal magnet

2018 ◽  
Vol 4 (11) ◽  
pp. eaau3402 ◽  
Author(s):  
R. Takagi ◽  
J. S. White ◽  
S. Hayami ◽  
R. Arita ◽  
D. Honecker ◽  
...  
Keyword(s):  
Magnetic Order ◽  
Interaction Mechanism ◽  
Spin Interaction ◽  
The Novel ◽  
Spin Order ◽  
Emergent Phenomena ◽  
Unique Material ◽  
Lattice State ◽  
Spin Texture ◽  
Different Origins

Multiple-q spin order, i.e., a spin texture characterized by a multiple number of coexisting magnetic modulation vectors q, has recently attracted attention as a source of nontrivial magnetic topology and associated emergent phenomena. One typical example is the triple-q skyrmion lattice state stabilized by Dzyaloshinskii-Moriya interactions in noncentrosymmetric magnets, while the emergence of various multiple-q states of different origins is expected according to the latest theories. Here, we investigated the magnetic structure of the itinerant polar hexagonal magnet Y3Co8Sn4, in which several distinctive mechanisms favoring multiple-q states are allowed to become active. Small-angle neutron-scattering experiments suggest the formation of incommensurate triple-q magnetic order with an in-plane vortex-like spin texture, which can be most consistently explained in terms of the novel four-spin interaction mechanism inherent to itinerant magnets. The present results suggest a new route to realizing exotic multiple-q orders and that itinerant hexagonal magnets, including the R3M8Sn4 family with wide chemical tunability, can be a unique material platform to explore their rich phase diagrams.

CFD-DEM Modeling of CO2 Capture using Alkali Metal-Based Sorbents in a Bubbling Fluidized Bed

2014 ◽  
Vol 12 (1) ◽  
pp. 441-449 ◽  
Author(s):  
Zhonglin Zhang ◽  
Daoyin Liu ◽  
Yaming Zhuang ◽  
Qingmin Meng ◽  
Xiaoping Chen
Keyword(s):  
Fluidized Bed ◽  
Gas Flow ◽  
Fluidized Bed Reactors ◽  
Solid Sorbents ◽  
Bubbling Fluidized Bed ◽  
Shrinking Core ◽  
Simulation And Experiment ◽  
Kinetics Simulation ◽  
Reaction Processes ◽  
Back Mixing

Abstract This paper describes a CFD-DEM modeling of CO2 capture using K2CO3 solid sorbents in a bubbling fluidized bed, which takes into heat transfer, hydrodynamics, and chemical reactions. Shrinking core model is applied in reaction kinetics. Simulation and experiment results of bed pressure drop and CO2 concentration in the reactor exit agree well. Instantaneous dynamics as well as time-averaged profiles indicate detailed characteristics of gas flow, particle motion, and chemical reaction processes. The simulation results show an obvious core-annular flow and strong back-mixing flow pattern. CO2 concentration decreases gradually along the bed height, while regards on the lateral distribution CO2 concentration near the wall is lower than that in the middle zone where gas passes through faster. The effect of bubbles on CO2 reaction is two-sided: it can promote mixing which strengthens reaction, while it can be a short pass of gas which is not beneficial to reaction. The simulation is helpful for further understanding and optimal design of fluidized bed reactors of CO2 capture.

scholarly journals Nanopowder Fluidization Using the Combined Assisted Fluidization Techniques of Particle Mixing and Flow Pulsation

2019 ◽  
Vol 9 (3) ◽  
pp. 572 ◽  
Author(s):  
Syed Ali ◽  
Avijit Basu ◽  
Sulaiman Alfadul ◽  
Mohammad Asif
Keyword(s):  
Fluidized Bed ◽  
Gas Flow ◽  
Substantial Reduction ◽  
Data Acquisition System ◽  
Gas Flow Rate ◽  
Flow Pulsation ◽  
Pressure Transducers ◽  
Particle Mixing ◽  
Group A ◽  
Sensitive Pressure

In the present study, we report the fluidization behavior of ultrafine nanopowder using the assisted fluidization technique of particle mixing, which was further superimposed with the pulsation of the inlet gas flow to the fluidized bed. The powder selected in the present study was hydrophilic nanosilica, which shows strong agglomeration behavior leading to poor fluidization hydrodynamics. For particle mixing, small proportions of inert particles of Geldart group A classification were used. The inlet gas flow to the fluidized bed was pulsed with a square wave of frequency 0.1 Hz with the help of a solenoid valve controlled using the data acquisition system (DAQ). In addition to the gas flow rate to the fluidized bed, pressure transients were carefully monitored using sensitive pressure transducers connected to the DAQ. Our results indicate a substantial reduction in the effective agglomerate size as a result of the simultaneous implementation of the assisted fluidization techniques of particle mixing and flow pulsation.

scholarly journals Biomimetic Functional Surfaces towards Bactericidal Soft Contact Lenses

Micromachines ◽  
2020 ◽  
Vol 11 (9) ◽  
pp. 835
Author(s):  
Tianyu Mao ◽  
Fengzhou Fang
Keyword(s):  
Aspect Ratio ◽  
High Aspect Ratio ◽  
Contact Lenses ◽  
Influence Factors ◽  
Interaction Mechanism ◽  
Holistic Approach ◽  
Geometrical Parameters ◽  
Physical Interaction ◽  
Soft Contact ◽  
Soft Contact Lenses

The surface with high-aspect-ratio nanostructure is observed to possess the bactericidal properties, where the physical interaction between high-aspect-ratio nanostructure could exert sufficient pressure on the cell membrane eventually lead to cell lysis. Recent studies in the interaction mechanism and reverse engineering have transferred the bactericidal capability to artificial surface, but the biomimetic surfaces mimicking the topographical patterns on natural resources possess different geometrical parameters and surface properties. The review attempts to highlight the recent progress in bactericidal nanostructured surfaces to analyze the prominent influence factors and cell rupture mechanism. A holistic approach was utilized, integrating interaction mechanisms, material characterization, and fabrication techniques to establish inclusive insights into the topographical effect and mechano-bactericidal applications. The experimental work presented in the hydrogel material field provides support for the feasibility of potentially broadening applications in soft contact lenses.

Predicting bed dynamics in three-phase, fluidized-bed biofilm reactors

1994 ◽  
Vol 29 (10-11) ◽  
pp. 231-241 ◽  
Author(s):  
H. T. Chang ◽  
B. E. Rittmann
Keyword(s):  
Fluidized Bed ◽  
Flow Rate ◽  
Liquid Flow ◽  
Gas Flow ◽  
Liquid Flow Rate ◽  
Gas Flow Rate ◽  
Biofilm Growth ◽  
Biofilm Thickness ◽  
Three Phase ◽  
Proper Design

This paper presents a unified model that inter-relates gas flow rate, liquid flow rate, and hold-ups of each of the liquid, gas, and solid phases in three-phase, fluidized-bed biofilm (TPFBB) process. It describes how carrier properties, biofilm properties, and gas and liquid flow velocities control the system dynamics, which ultimately will affect the density, thickness, and distribution of the biofilm. The paper describes the development of the mathematical model to correlate the effects of gas flow rate, liquid flow rate, solid concentration, and biofilm thickness and density. This knowledge is critically needed in light of the use of TPFBB processes in treating industrial wastewater, which often has high substrate concentration. For example, the proper design of the TPFBB process requires mathematical description of the cause-effect relationship between biofilm growth and fluidization.

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