Study on the combined effect of thixotropy, particle shape, and particle size on cuttings transport in horizontal annuli

2021 ◽  
Author(s):  
Shiraz Gulraiz ◽  
K.E. Gray
Keyword(s):  
Particle Size ◽  
Particle Shape ◽  
Combined Effect ◽  
Cuttings Transport ◽  
Horizontal Annuli

Modelling Particle Size Distribution of Residual Fly Ash from Pulverized Biomass Combustion

2021 ◽  
Vol 15 (1) ◽  
pp. 75-82
Author(s):  
Mingzi Xu ◽  
Changdong Sheng
Keyword(s):  
Particle Size ◽  
Fly Ash ◽  
Simple Model ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Particle Shape ◽  
Great Influence ◽  
Biomass Combustion ◽  
Ash Formation ◽  
Residual Ash

The present work aims to develop a simple model for describing the particle size distribution (PSD) of residual fly ash from pulverized biomass combustion. The residual ash formation was modelled considering the mechanism of fragmentation and coalescence. The influences of particle shape and stochastic fragmentation on model description of the PSD of the fly ash were investigated. The results showed that biomass particle shape has a great influence on the model prediction, and a larger fragmentation number is required for cylindrical particles than that for spherical particles to get the same PSD of fly ash, and the fragment number of the particles increases with the shape factor increasing. For pulverized biomass with a wide size distribution, the model predicted ash PSD considering the stochastic fragmentation is very similar to that assuming uniform fragmentation. It implies that the simple model assuming uniform fragmentation is applicable for predicting fly ash size distribution in practical processes where biomass particles have a wide range of sizes. For the fuel with a narrower initial PSD, the stochastic fragmentation model generally predicts a coarser PSD of the residual ash than assuming uniform fragmentation. It means the stochastic fragmentation is of great influence to be considered for accurate description of ash formation from the fuel with a narrow PSD.

scholarly journals EFFECTS OF PARTICLE SIZE AND PARTICLE SHAPE IN FLOW SIMULATIONS OF DRY SAND USING DEM

2015 ◽  
Vol 71 (2) ◽  
pp. I_587-I_594
Author(s):  
Shuji MORIGUCHI ◽  
Yuta HIRUMA ◽  
Shinsuke TAKASE ◽  
Kenjiro TERADA
Keyword(s):  
Particle Size ◽  
Particle Shape ◽  
Flow Simulations ◽  
Dry Sand

scholarly journals Optimization of nanostructured/nano sized rice husk ash preparation

2020 ◽  
Vol 17 (3(Suppl.)) ◽  
pp. 0953
Author(s):  
Medhat Mostafa ◽  
Hamdy Salah ◽  
Amro B. Saddek ◽  
Nabila Shehata
Keyword(s):  
Particle Size ◽  
Rice Husk ◽  
Amorphous Silica ◽  
Particle Shape ◽  
Rice Husk Ash ◽  
Loss On Ignition ◽  
Shape Distribution ◽  
Disk Mill ◽  
Grinding Time

The objective of the study is developing a procedure for production and characterization of rice husk ash (RHA). The effects of rice husk (RH) amount, burning/cooling conditions combined with stirring on producing of RHA with amorphous silica, highest SiO2, lowest loss on ignition (LOI), uniform particle shape distribution and nano structured size have been studied. It is concluded that the best amount is 20 g RH in 125 ml evaporating dish Porcelain with burning for 2 h at temperature 700 °C combined with cooling three times during burning to produce RHA with amorphous silica, SiO2 90.78% and LOI 1.73%. On the other hand, cooling and stirring times affect the variation of nano structured size and particle shape distribution. However, no crystalline phases were found in RHA in all cases. Results proved that the Attritor ball mill was more suitable than vibration disk mill for pulverizing nano structured RHA with 50% of particle size (D50) lower than 45 mm and 99 % of particle size (D99) lower than 144 mm to nanosized RHA with D50 lower than 36 nm and D99 lower than 57 nm by grinding time 8.16 min to every 1 g RHA without changes in morphousity of silica.

Prediction of Packing Density of Milled Powder Based on Packing Simulation and Particle Shape Analysis

2007 ◽  
Vol 534-536 ◽  
pp. 1621-1624
Author(s):  
Yuto Amano ◽  
Takashi Itoh ◽  
Hoshiaki Terao ◽  
Naoyuki Kanetake
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Shape Analysis ◽  
Packing Density ◽  
Particle Shape ◽  
Milled Powder ◽  
Spherical Particles ◽  
Nonspherical Particles ◽  
Property Control

For precise property control of sintered products, it is important to know the powder characteristics, especially the packing density of the powder. In a previous work, we developed a packing simulation program that could make a packed bed of spherical particles having particle size distribution. In order to predict the packing density of the actual powder that consisted of nonspherical particles, we combined the packing simulation with a particle shape analysis. We investigated the influence of the particle size distribution of the powder on the packing density by executing the packing simulation based on particle size distributions of the actual milled chromium powders. In addition, the influence of the particle shape of the actual powder on the packing density was quantitatively analyzed. A prediction of the packing density of the milled powder was attempted with an analytical expression between the particle shape of the powder and the packing simulation. The predicted packing densities were in good agreement with the actual data.

scholarly journals Effect of particle size distribution on rheological properties of chocolate

2020 ◽  
Vol 11 (11) ◽  
pp. 9547-9559
Author(s):  
Annika Feichtinger ◽  
Elke Scholten ◽  
Guido Sala
Keyword(s):  
Surface Roughness ◽  
Particle Size ◽  
Particle Size Distribution ◽  
Rheological Properties ◽  
Size Distribution ◽  
Particle Shape ◽  
Size Ratio ◽  
Particle Size Ratio ◽  
Effect Of Particle Size

Particle size distribution and particle size ratio have an important effect on rheological properties of model chocolate samples, but also other factors like particle shape, surface roughness and hydrophilicity should be taken into account.

scholarly journals Numerical Simulation of Solid Particle Erosion in Aluminum Alloy Spool Valve

2019 ◽  
Vol 2019 ◽  
pp. 1-16 ◽  
Author(s):  
Jin-gang Liu ◽  
Gao-sheng Wang ◽  
Tian-heng Peng ◽  
Sheng-qiang Jiang
Keyword(s):  
Particle Size ◽  
Aluminum Alloy ◽  
Prediction Model ◽  
Particle Shape ◽  
Two Phase ◽  
Wear Prediction ◽  
Valve Body ◽  
Fluent Software ◽  
Improved Design ◽  
Spool Valve

Aluminum alloy spool valve body material is prone to severe wear on the wall under the condition of oil contamination. Aiming at this problem, combined with the theory of liquid-solid two-phase flow and erosion wear, the wear prediction model of aluminum alloy sliding valve wall is established based on computational fluid dynamics, and the effects of turbulence and wall materials, particle size distribution, and particle shape on particle motion are discussed. The calculation of the wear prediction model is done with Fluent software. This study predicts the wear of the wall under actual working conditions and calculates the influence of particle size, particle shape, and pressure difference on the wall wear of the aluminum alloy sliding valve. The research results have certain significance for the maintenance and upkeep of aluminum alloy sliding valve wall, improved design, and life prediction.

scholarly journals Prediction Model of Minimum Void Ratio for Various Sizes/Shapes of Sandy Binary Mixture

2020 ◽  
Vol 2020 ◽  
pp. 1-19
Author(s):  
Chaojie Shen ◽  
Zhaoyang Xu ◽  
Jie Yin ◽  
Jinfeng Wu
Keyword(s):  
Particle Size ◽  
Binary Mixture ◽  
Particle Shape ◽  
Void Ratio ◽  
Soil Mechanics ◽  
Influence Factors ◽  
Natural Sand ◽  
Undetermined Coefficient ◽  
Shape Characteristics ◽  
Different Origins

The minimum void ratio is a fundamental physical index for evaluating particle properties in soil mechanics, ceramic processing, and concrete mixes. Previous research found that both particle size distribution and particle shape characteristics would affect minimum void ratio, while the current research generally uses a linear model to estimate the minimum void ratio of a binary mixture, ignoring quantitative effect of particle shape on the minimum void ratio. Based on a study of binary mixtures of natural sand from three different origins and iron particles of two different shapes, this paper analyzes the influence factors of the minimum void ratio, and a quadratic nonlinear model is proposed for estimating the minimum void ratio of binary mixture. The model contains only one undetermined coefficient, a, the value of which is correlated to the particle sphericity, particle size, and particle size ratio. A theoretical calculation formula for the coefficient a is proposed to quantitatively analyze the effects of these three factors on the size of the parameters. In the end, the model is used to estimate the minimum void ratios of sand and substitute particles from different producing areas; the average difference between the estimated values and the fitted values is about 2.03%, suggesting that the estimated values of the model fit well with the measured data.

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