REVIEW OF APPLIED PARTICLE SHAPE DESCRIPTORS AND PRODUCED PARTICLE SHAPES IN GRINDING ENVIRONMENTS. PART I: PARTICLE SHAPE DESCRIPTORS

2005 ◽  
Vol 26 (2) ◽  
pp. 145-166 ◽  
Author(s):  
PARVIZ POURGHAHRAMANI ◽  
Eric Forssberg
Keyword(s):  
Particle Shape ◽  
Shape Descriptors ◽  
Particle Shapes

scholarly journals The effect of particle shape on the deformation and stress reduction of a gravel soil due to wetting

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Reza Mahinroosta ◽  
Vahid Oshtaghi
Keyword(s):  
Particle Size ◽  
Shear Stress ◽  
Particle Size Distribution ◽  
Normal Stress ◽  
Size Distribution ◽  
Stress Reduction ◽  
Particle Shape ◽  
Particle Breakage ◽  
Direct Shear ◽  
Particle Shapes

AbstractThis paper investigates the effect of particle shape on the stress reduction and collapse deformation of gravelly soil using a medium-scale direct shear test apparatus under different relative densities, normal stress, and shear stress levels. A new method based on the Micro-Deval test was introduced to produce sub-angular particles from angular particles. Therefore, two series of soil specimens were obtained with the same rock origin, particle size distribution, and relative density but different particle shapes. In addition to traditional direct shear tests on dry and wet specimens, a specific test procedure was applied to explore the stress reduction and collapse of soil specimens due to wetting. The results of the tests, including shear stress–shear displacement and vertical displacement-shear displacement, were compared. The results showed that the stress reduction and settlement due to wetting increased with vertical and shear stress levels in both types of particle shapes, with higher values in angular particle shapes. The particle breakage of the soil specimens was also studied quantitatively using the change in the particle size distribution before and after the test. It was shown that the wetting of the samples had more impact on the particle breakage in angular gravel than sub-angular gravel, which increased linearly with the normal stress.

scholarly journals Frac sand crushing characteristics and morphology changes under high compressive stress and implications for sand pack permeability

2016 ◽  
Vol 53 (9) ◽  
pp. 1412-1423 ◽  
Author(s):  
Wenbo Zheng ◽  
Dwayne Tannant
Keyword(s):  
Particle Shape ◽  
Void Ratio ◽  
Size Range ◽  
Particle Sizes ◽  
Shale Formations ◽  
Closure Stress ◽  
Compressive Stresses ◽  
Spherical Grains ◽  
Particle Shapes ◽  
Quartz Grains

Sand consisting of round quartz grains is widely used as a proppant during hydraulic fracturing to produce natural gas from tight shale formations. This paper presents results from sand characterization and crushing tests on Jordan Formation frac sand. It includes an assessment of grain-size reduction, changes in particle shape, and reduction in void ratio. It also examines the implications for permeability reduction through a sand pack caused by the closure stress on a hydraulic fracture. The sand from two size ranges (0.6 to 0.71 mm and 0.5 to 0.6 mm) was tested dry under applied compressive stresses of up to 40 MPa in a crushing cup. The overall sand pack stress–strain response becomes softer as grains are crushed. The particle shape shifts from nearly spherical grains to diametrically split grains and then to small elongated and angular fragments for the smaller particle sizes. The permeability of the sand pack reduces by more than 40% at a 20 MPa stress, which is mainly caused by a decrease in void ratio due to compaction. The permeability reduces by over 70% at a 40 MPa stress, which is primarily caused by void ratio decrease, reduction in particle size, and a shift away from spherical particle shapes. Compared to the ISO 13503-2 standard where only the sand crushing percentage after crushing tests is measured, this paper demonstrates that more information can be extracted from sand crushing tests and that sand pack permeability can be assessed to optimize frac sand selection. A sand with a larger size range has a higher crushing percentage, but is more permeable compared to a sand with a smaller size range. This further indicates that frac sand selection based only on sand crushing percentage is not sufficient to achieve better sand pack permeability.

Kinetic Simulations for Analysing the Wall Collision Process of Non-Spherical Particles

2002 ◽  
Author(s):  
M. Sommerfeld
Keyword(s):  
Particle Shape ◽  
Fluid Dynamic ◽  
Impact Angle ◽  
Distribution Functions ◽  
Spherical Particles ◽  
Collision Process ◽  
Wall Collision ◽  
Particle Velocities ◽  
The Impact ◽  
Particle Shapes

In wall-bounded gas-solid flows the wall collision process plays an important role and may be strongly affected by wall roughness and particle shape. The modelling of the particle-wall collision mostly relies on the assumption of spherical particles. To extend such models appropriately for non-spherical particles, two-dimensional kinetic simulations were performed for different particle shapes. This implies, that the particle translational and angular motion is calculated by considering the particle shape, however neglecting fluid dynamic effects. The change of the particle velocities during the impact and rebound process was calculated by solving the impulse equations together with Coulombs law of friction. The simulations were performed for a given initial particle velocity by varying impact angle and initial angular velocity. The results for 2000 particle wall collisions allowed us to derive the distribution functions of the impact parameters required to describe the wall collision process for non-spherical particles correctly. Moreover, other wall collision properties, such as rebound angle and velocity ratios could be determined. Finally also a comparison with measurements was possible.

scholarly journals Particle shape characterisation and classification using automated microscopy and shape descriptors in batch manufacture of particulate solids

Particuology ◽  
2016 ◽  
Vol 24 ◽  
pp. 61-68 ◽  
Author(s):  
Yang Zhang ◽  
Jing J. Liu ◽  
Lei Zhang ◽  
Jorge Calderon De Anda ◽  
Xue Z. Wang
Keyword(s):  
Particle Shape ◽  
Shape Descriptors ◽  
Particulate Solids ◽  
Automated Microscopy

scholarly journals Computational Investigation of Liquid Holdup and Wetting Efficiency Inside Trickle Bed Reactors with Different Catalyst Particle Shapes

2020 ◽  
Vol 10 (4) ◽  
pp. 1436
Author(s):  
Hao Deng ◽  
Baoqi Guo ◽  
He Dong ◽  
Cheng Liu ◽  
Zhongfeng Geng
Keyword(s):  
Fluid Flow ◽  
Particle Shape ◽  
Particle Surface ◽  
Liquid Density ◽  
Reactor Performance ◽  
Liquid Holdup ◽  
Trickle Bed Reactors ◽  
Vof Model ◽  
Trickle Bed ◽  
Particle Shapes

Liquid holdup and wetting efficiency are essential parameters for design of trickle bed reactors. Both parameters play an important role in reactor performance including pressure drop, conversion, and heat transfer. Empirical formulas are usually employed to calculate liquid holdup and wetting efficiency. However, factors such as particle shape and the wetting ability of liquid on the particle surface are not described clearly in traditional formulas. In this paper, actual random packing was built by DEM and CFD simulations were performed to investigate the factors affecting liquid holdup and wetting efficiency in trickle bed reactors, including particle shape, surface tension, contact angle, liquid viscosity, liquid density, liquid, and gas superficial velocity. Detailed fluid flow and liquid-solid interaction were described by VOF model. Four different particle shapes were investigated. It showed the particle shape has great effect and the 4-hole cylinder packing gained both highest liquid holdup and wetting efficiency. The overall simulations gave a detailed description of phase interactions and fluid flow in the voids between catalyst particles and these results could give further guidance for the design and operation of trickle bed reactors.

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