Model of fluidized bed expansion

1979 ◽  
Vol 44 (1) ◽  
pp. 50-55
Author(s):  
Benitto Mayrhofer ◽  
Lubomír Neužil ◽  
František Procháska
Keyword(s):  
Experimental Data ◽  
Fluidized Bed ◽  
Fixed Bed ◽  
Theoretical Models ◽  
Creeping Flow ◽  
Spherical Particles ◽  
Bed Porosity ◽  
Porosity Dependence ◽  
Bed Expansion ◽  
Better Than

Theoretical relations have been derived for the superficial velocity of fluidization under the creeping flow regime for cubic, monoclinic and tetrahedron configurations of spherical particles. The models proposed have been compared with theoretical models published up to the present and with the power-law correlations recommended. The configuration fitting the best was found to be the tetrahedron one. All configurations examined in this work gave correct trend of the velocity of fluidization versus porosity dependence. Experimental data indicate that for the bed porosity ranging between 0.45 and 0.68 our models are better than other so far published. However theoretical models of other authors based on the analysis of the behavior of a fixed bed give better results.

Approximate Solution of Momentum Transfer in System Generalized Newtonian Fluid-Fluidized Bed of Spherical Particles Using Modified Rabinowitsch-Mooney Equation

1995 ◽  
Vol 60 (8) ◽  
pp. 1281-1296 ◽  
Author(s):  
Václav Dolejš ◽  
Petr Mikulášek ◽  
Petr Doleček
Keyword(s):  
Approximate Solution ◽  
Momentum Transfer ◽  
Fluidized Bed ◽  
Newtonian Fluid ◽  
Particle Diameter ◽  
Flow Region ◽  
Creeping Flow ◽  
Spherical Particles ◽  
Generalized Newtonian Fluid ◽  
Mooney Equation

The modified Rabinowitsch-Mooney equation together with the corresponding relations for consistency variables has been adopted for approximate solution of momentum transfer between generalized Newtonian fluid with laminar flow and surface of fluidized bed of spherical particles inclusive of wall surface. The solution has been concretized for a fluid characterized by power-law and Ellis flow models in the creeping flow region. The range of values of ratios of particle diameter to column diameter and that of porosity values e in which the suggested relation satisfactorily agrees with experimental results for pseudoplastic fluids have been delimitated experimentally.

scholarly journals HYDRODINAMIC STUDY OF CLAY PARTICLES IN FLUIDIZED BED

2016 ◽  
Vol 19 (2) ◽  
Author(s):  
GABRIELA MUNTIANU ◽  
NICOLETA PLATON ◽  
VASILICA ALISA ARUS ◽  
ANA MARIA ROSU ◽  
DENISA ILEANA NISTOR ◽  
...  
Keyword(s):  
Fluidized Bed ◽  
Fixed Bed ◽  
Pillared Clay ◽  
Gas Velocity ◽  
Optimal Operating ◽  
Minimum Fluidization Velocity ◽  
Clay Particles ◽  
Minimal Error ◽  
Bed Porosity ◽  
Bed Height

The aim of the present study was to establish the optimal operating dynamic parameters in fluidized bed for the sodium clay particles and pillared clay particles. In order to determine the influence of the clay particles on the structure of the fluidized bed, the conditions in which the incipient fluidization appears were determined depending on the: nature, diameter and density of the material, gas velocity and fixed bed height. Experimentally the minimum fluidization velocity, the minimum pressure drop and bed porosity were determined. Correlation relations were established in order to approximate the minimal error for the experimental results.

scholarly journals Simulation on hydrodynamics of non-spherical particulate system using a drag coefficient correlation based on artificial neural network

2019 ◽  
Vol 17 (2) ◽  
pp. 537-555
Author(s):  
Sheng-Nan Yan ◽  
Tian-Yu Wang ◽  
Tian-Qi Tang ◽  
An-Xing Ren ◽  
Yu-Rong He
Keyword(s):  
Neural Network ◽  
Experimental Data ◽  
Artificial Neural Network ◽  
Drag Coefficient ◽  
Fluidized Bed ◽  
Spherical Particles ◽  
Coefficient Corrélation ◽  
Bubbling Fluidized Bed ◽  
Simulation Results ◽  
Artificial Neural

AbstractFluidization of non-spherical particles is very common in petroleum engineering. Understanding the complex phenomenon of non-spherical particle flow is of great significance. In this paper, coupled with two-fluid model, the drag coefficient correlation based on artificial neural network was applied in the simulations of a bubbling fluidized bed filled with non-spherical particles. The simulation results were compared with the experimental data from the literature. Good agreement between the experimental data and the simulation results reveals that the modified drag model can accurately capture the interaction between the gas phase and solid phase. Then, several cases of different particles, including tetrahedron, cube, and sphere, together with the nylon beads used in the model validation, were employed in the simulations to study the effect of particle shape on the flow behaviors in the bubbling fluidized bed. Particle shape affects the hydrodynamics of non-spherical particles mainly on microscale. This work can be a basis and reference for the utilization of artificial neural network in the investigation of drag coefficient correlation in the dense gas–solid two-phase flow. Moreover, the proposed drag coefficient correlation provides one more option when investigating the hydrodynamics of non-spherical particles in the gas–solid fluidized bed.

Mass Transfer in Oil Sand Fluidized Beds—A Simplified Model

1988 ◽  
Vol 110 (4) ◽  
pp. 279-283
Author(s):  
M. A. Abdrabboh ◽  
G. A. Karim
Keyword(s):  
Experimental Data ◽  
Mass Transfer ◽  
Closed Form ◽  
Fluidized Bed ◽  
Oil Sands ◽  
Fluidized Beds ◽  
Spherical Particles ◽  
Simplified Model ◽  
Oil Sand ◽  
Uniform Velocity

Experimental data obtained previously relating to the behavior of single spherical particles of oil sands in hot uniform velocity oxidizing gaseous streams were employed and extended to estimate in a preliminary fashion the extent of mass transfer from oil sand fragments in a fluidized bed. This has been done through employing experimental correlations published in the literature on fluidization. A simple closed-form analytical expression was derived for estimating the transient rates of mass transfer in fluidized beds of oil sands in terms of the main controlling parameters.

Modelling and Experiments on Fluidized-Bed Biofilm Reactors

1991 ◽  
Vol 24 (7) ◽  
pp. 47-58 ◽  
Author(s):  
L. Bignami ◽  
B. Eramo ◽  
R. Gavasci ◽  
R. Ramadori ◽  
E. Rolle
Keyword(s):  
Fluidized Bed ◽  
Liquid Velocity ◽  
Fluid Dynamic ◽  
Fixed Bed ◽  
Experimental Tests ◽  
Rational Basis ◽  
Biofilm Reactors ◽  
Bed Porosity ◽  
Batch Tests ◽  
Biofilm Model

Over the last few years considerable attention has been devoted to biological fluidized-bed technology which seems to be potentially more advantageous than both dispersed biomass processes and fixed bed systems. An obstacle to the spreading of this technology is the lack of rigorous criteria in designing reactors, due to the poor knowledge of interconnections of fluid-dynamic aspects with kinetic ones. This paper reviews the rational basis for reactor design and reports on the experimental tests carried out in order to gain a better understanding in the areas of biofilm modelling and fluidization mechanics. In particular a biofilm model, in the general case of the Michaelis and Menten equation, was developed and its validity was verified utilizing experimental data obtained in nitrifying batch tests. As to fluidization mechanics the experimental work confirms the Wen and Yu(1966) approach to correlate the bed porosity with the superficial liquid velocity.

The analysis of the relations between porosity and tortuosity in granular beds

2017 ◽  
Vol 1 (20) ◽  
pp. 75-85 ◽  
Author(s):  
Wojciech Sobieski ◽  
Seweryn Lipiński
Keyword(s):  
Lattice Boltzmann ◽  
Creeping Flow ◽  
Spherical Particles ◽  
Particle Sizes ◽  
Granular Bed ◽  
Tracking Method ◽  
Bed Porosity ◽  
Relative Errors ◽  
Boltzmann Method ◽  
Path Tracking Method

In the paper, functions describing different porosity-tortuosity relations were collected, and then the tortuosity values were calculated for a one granular bed consisting of spherical particles with normal distribution of diameters. Information about the bed porosity and particle sizes was obtained from measurements conducted for an artificial granular bed, consisting of glass marbles. The results of calculations were compared with the results of two other methods of tortuosity determination, performed for the same case (details are not described in this paper): the first of them uses the Path Tracking Method, the second one - information about the velocity components in a creeping flow (the Lattice-Boltzmann Method was applied to obtain the velocity field in the flow). The main aim of our article was to test whether the functions linking tortuosity with porosity, which are available in the literature, give similar results as the methods described above. To achieve this aim, the relative errors between results of calculations for the collected formulas and values from the both previous mentioned methods were calculated.

Estimating ink mileage of dry toners in electrophotography

TAPPI Journal ◽  
2013 ◽  
Vol 12 (3) ◽  
pp. 9-14
Author(s):  
RENMEI XU ◽  
CELESTE M. CALKINS
Keyword(s):  
Experimental Data ◽  
Curve Fitting ◽  
Graphite Furnace ◽  
Atomic Absorption Spectrometer ◽  
Density Region ◽  
Coated Papers ◽  
Graphite Furnace Atomic Absorption ◽  
S Model ◽  
Better Than ◽  
Film Weight

This work investigates the ink mileage of dry toners in electrophotography (EP). Four different substrates were printed on a dry-toner color production Xerox iGen3 EP press. The print layout contained patches with different cyan, magenta, yellow, and black tonal values from 10% to 100%. Toner amounts on cyan patches were measured using an analytical method. Printed patches and unprinted paper samples, as well as dry toners, were dissolved in concentrated nitric acid. The copper concentrations in the dissolved solutions were analyzed by a Zeeman graphite furnace atomic absorption spectrometer. Analytical results were calculated to determine the toner amounts on paper for different tonal values. Their corresponding reflection densities were also measured. All data were plotted with OriginPro® 8 software, and four mathematical models were used for curve fitting. It was found that the C-S model fitted the experimental data of the two uncoated papers better than the other three models. None of the four models fitted the experimental data of the two coated papers, while the linear model was found to fit the data well. Linear fitting was the best in the practical density region for the two coated papers. Ink mileage curves obtained from curve fitting were used to estimate how much ink was required to achieve a target density for each paper; hence, the ink mileage was calculated. The highest ink mileage was 3.39 times the lowest ink mileage. The rougher the paper surface, the higher the requirement for ink film weight, and the lower ink mileage. No correlation was found between ink mileage and paper porosity.

TEMPERATURE DEPENDENCE BEHAVIOR OF ELECTRICAL RESISTIVITY IN NOBLE METALS AT LOW TEMPERATURES

2014 ◽  
Vol 5 (3) ◽  
pp. 982-992 ◽  
Author(s):  
M AL-Jalali
Keyword(s):  
Experimental Data ◽  
Electrical Resistivity ◽  
Temperature Dependence ◽  
Concentration Dependence ◽  
Low Temperatures ◽  
Noble Metals ◽  
Phonon Scattering ◽  
Theoretical Models ◽  
Residual Resistivity ◽  
Electron Phonon Scattering

Resistivity temperature – dependence and residual resistivity concentration-dependence in pure noble metals(Cu, Ag, Au) have been studied at low temperatures. Dominations of electron – dislocation and impurity, electron-electron, and electron-phonon scattering were analyzed, contribution of these mechanisms to resistivity were discussed, taking into consideration existing theoretical models and available experimental data, where some new results and ideas were investigated.

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