Analysis of flow behavior of size distributed spherical particles in screw feeder

2020 ◽  
Author(s):  
Dheeraj Minglani ◽  
Abhishek Sharma ◽  
Harsh Pandey ◽  
Ram Dayal ◽  
Jyeshtharaj B. Joshi
Keyword(s):  
Flow Behavior ◽  
Spherical Particles ◽  
Screw Feeder

Analysis of flow behavior of cohesive monosized spherical and non-spherical particles in screw feeder

2021 ◽  
pp. 117049
Author(s):  
Dheeraj Minglani ◽  
Abhishek Sharma ◽  
Harsh Pandey ◽  
Jyeshtharaj B. Joshi
Keyword(s):  
Flow Behavior ◽  
Spherical Particles ◽  
Screw Feeder

Oxidation Rate Analysis of Carbon Nanoparticles for a Small Particle Heat Exchange Receiver

2014 ◽  
Author(s):  
Mario Leoni ◽  
Lee Frederickson ◽  
Fletcher Miller
Keyword(s):  
Heat Exchange ◽  
Small Particle ◽  
Oxidation Rate ◽  
Flow Behavior ◽  
Average Diameter ◽  
Index Of Refraction ◽  
Spherical Particles ◽  
Extinction Cross Section ◽  
Carbon Particles ◽  
Rate Analysis

A new experimental set-up has been introduced at San Diego State University’s Combustion and Solar Energy Lab to study the thermal oxidation characteristics of in-situ generated carbon particles in air at high pressure. The study is part of a project developing a Small Particle Heat Exchange Receiver (SPHER) utilizing concentrated solar power to run a Brayton cycle. The oxidation data obtained will further be used in different existing and planned computer models in order to accurately predict reactor temperatures and flow behavior in the SPHER. The carbon black particles were produced by thermal decomposition of natural gas at 1250 °C and a pressure of 5.65 bar (82 psi). Particles were analyzed using a Diesel Particle Scatterometer (DPS) and scanning electron microscopy (SEM) and found to have a 310 nm average diameter. The size distribution and the complex index of refraction were measured and the data were used to calculate the specific extinction cross section γ of the spherical particles. The oxidation rate was determined using 2 extinction tubes and a tube furnace and the values were compared to literature. The activation energy of the carbon particles was determined to be 295.02 kJ/mole which is higher than in comparable studies. However, the oxidation of carbon particles bigger than 100 nm is hardly studied and almost no previous data is available at these conditions.

Model studies on distributions of blood cells at microvascular bifurcations

1985 ◽  
Vol 248 (4) ◽  
pp. H568-H576 ◽  
Author(s):  
S. Chien ◽  
C. D. Tvetenstrand ◽  
M. A. Epstein ◽  
G. W. Schmid-Schonbein
Keyword(s):  
Red Blood Cells ◽  
Blood Cells ◽  
Particle Flux ◽  
Flow Behavior ◽  
Bulk Flow ◽  
Spherical Particles ◽  
Branch Points ◽  
Particle Distributions ◽  
Model Studies ◽  
Neutrally Buoyant

To model the flow behavior of white and red blood cells at microvascular branch points, the distribution of neutrally buoyant spherical and disk-shaped particles at a symmetric T bifurcation was investigated for low Reynolds number flows (0.01-0.1). The particle distribution was represented by the fractional particle flux to a daughter branch as a function of the fractional volumetric bulk flow to the same branch. Particle-to-tube diameter ratios of 0.32-0.79 were studied for the spherical particles and 0.4-0.8 for the disks. As the particle dimensions approach that of the tube, the relation between the fractional particle flux and fractional bulk flow changes from a linear relation of unity slope to a nonlinear S-shaped curve. Measurements of the flow divider at the entrance to the bifurcation and the eccentricity distributions for the spheres and disks were used to develop a model that permits prediction of the observed particle distributions. These results can be used to interpret the distribution of white and red blood cells in microvascular bifurcations with dimensions close to the cell size.

Investigation of the Flow Behavior of Participate Filled Fluids

1996 ◽  
Vol 445 ◽  
Author(s):  
T. E. Driscoll ◽  
P. C. Li ◽  
G. L. Lehmann ◽  
E. J. Cotts
Keyword(s):  
Large Particle ◽  
Capillary Flow ◽  
Flow Behavior ◽  
Solid Particles ◽  
Spherical Particles ◽  
Liquid Density ◽  
High Concentration ◽  
Flow Process ◽  
Fluid Mixture ◽  
Underfill Flow

AbstractUnderfill encapsulants, used in direct‐chip‐attachment (DCA) packaging of electronics, consist of an epoxy resin in which a high concentration of solid particles are suspended. As a fluid mixture key features of these encapsulants are their relatively large particle sizes and large particle‐to‐liquid density ratios (ρs/ρ0 ?2.4). Experiments have been conducted to characterize the flow behavior of model mixtures of negatively buoyant, spherical particles suspended in Newtonian liquids. Capillary flow in a parallel surface channel is used to simulate the underfill flow process. The effects of varying the channel spacing, particle size and liquid carrier are reported here. The flow behavior is contrasted with a linear fluid, effective viscosity model. Particle settling appears to be linked to the more complex behavior observed in both our model suspensions and measurements using an actual commercial encapsulant.

Effect of screw design on hopper drawdown of spherical particles in a horizontal screw feeder

2011 ◽  
Vol 66 (22) ◽  
pp. 5585-5601 ◽  
Author(s):  
Justin W. Fernandez ◽  
Paul W. Cleary ◽  
William McBride
Keyword(s):  
Spherical Particles ◽  
Screw Design ◽  
Screw Feeder

scholarly journals Modelling of the Separation Process in a Ferrohydrostatic Separator Using Discrete Element Method

2007 ◽  
Vol 2007 ◽  
pp. 1-13 ◽  
Author(s):  
V. Murariu ◽  
P. J. Sergeant
Keyword(s):  
Discrete Element Method ◽  
Flow Behavior ◽  
Discrete Element ◽  
Separation Process ◽  
Spherical Particles ◽  
Particle Flow Code ◽  
Complex Flow ◽  
De Beers ◽  
Simulation Parameters ◽  
Element Method

This paper presents a model of the separation process in a ferrohydrostatic separator (FHS) which has been designed and developed at DBGS, De Beers, South Africa. The model was developed using special discrete element method software package called Particle Flow Code in 3D (PFC3D). Special attention has been paid to the selection of the simulation parameters in order to achieve the required feed rates. The simulation was carried out using spherical particles and density tracers of different sizes and densities ranging between 0.004 and 0.008 m and 2700 and 3800 kg/m3, respectively. The tracers were used to set the apparent density of the ferrofluid (the cut-point) and to provide a measurement of the efficiency of the separation. The model is replacing the ferrofluid by imposing a drag force on the particle. The results of the simulation were presented in the form of the distribution of the density tracers into the sink fraction. These results are realistic and show the advantages of DEM to understand the complex flow behavior of granular materials.

CFD Modelling of the Dehydrogenation Reaction of Isobutane to Isobutylene in a Fixed Bed Reactor

2016 ◽  
Author(s):  
Tarek J. Jamaleddine ◽  
Ramsey M. Bunama
Keyword(s):  
Flow Behavior ◽  
Fixed Bed ◽  
Fixed Bed Reactor ◽  
Spherical Particles ◽  
Similar Process ◽  
Catalytic Dehydrogenation ◽  
Cfd Modelling ◽  
Dehydrogenation Reaction ◽  
Oxide Support ◽  
Reaction Models

The catalytic dehydrogenation reaction of isobutane to isobutylene is simulated in a commercial-scale heterogenous fixed bed reactor (FBR). The porous medium method in ANSYS Fluent combined with the reaction model capability was utilized to predict the flow behavior and species transport in a bed of spherical particles. Physical and material properties of a dehydrogenating catalyst of Chromium Oxide (Cr2O3) on Aluminum Oxide Support (Al2O3) were employed in the model. Several reaction models were implemented using a customized User-defined Function (UDF) subroutine. Simulation results were validated against literature data for a similar process. Good agreement was observed for the conversion of alkanes to alkenes within acceptable accuracy. It is concluded that the power-law model showed the least fit for the feed conversion and product selectivity compared to the other studied reaction models.

STEM Study of Surface Plasmon Excitation in Small Spherical Particles

1990 ◽  
Vol 48 (2) ◽  
pp. 42-43
Author(s):  
Daniel UGARTE
Keyword(s):  
Energy Loss ◽  
Spherical Particles ◽  
Small Particles ◽  
Bulk Materials ◽  
Low Loss ◽  
Plasmon Excitation ◽  
Surface Modes ◽  
Surface Plasmon Excitation ◽  
Analytical Electron ◽  
Analytical Electron Microscope

Small particles exhibit chemical and physical behaviors substantially different from bulk materials. This is due to the fact that boundary conditions can induce specific constraints on the observed properties. As an example, energy loss experiments carried out in an analytical electron microscope, constitute a powerful technique to investigate the excitation of collective surface modes (plasmons), which are modified in a limited size medium. In this work a STEM VG HB501 has been used to study the low energy loss spectrum (1-40 eV) of silicon spherical particles [1], and the spatial localization of the different modes has been analyzed through digitally acquired energy filtered images. This material and its oxides have been extensively studied and are very well characterized, because of their applications in microelectronics. These particles are thus ideal objects to test the validity of theories developed up to now.Typical EELS spectra in the low loss region are shown in fig. 2 and energy filtered images for the main spectral features in fig. 3.

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