Monte Carlo Simulations of Micro-Particle Detachment and Resuspension From Surfaces in Turbulent Flows

2012 ◽  
Author(s):  
Iman Goldasteh ◽  
Goodarz Ahmadi ◽  
Andrea Ferro
Keyword(s):  
Surface Roughness ◽  
Particle Size ◽  
Monte Carlo ◽  
Turbulent Flow ◽  
Size Distribution ◽  
Rough Surfaces ◽  
Spherical Particles ◽  
Particle Adhesion ◽  
Particle Detachment ◽  
Particle Resuspension

Micro-particle adhesion, detachment and resuspension from surfaces have attracted considerable attention due to their numerous applications in semiconductor, xerographic, and pharmaceutical industries, and, more recently, in understanding indoor air quality. However, most earlier studies have focused on idealized spherical particles and smooth surfaces, and the effects of particle irregularities and surface roughness on the rate of particle removal and resuspension are not well understood. In this work, a Monte Carlo simulation of particle resuspension from a surface under turbulent flow conditions was developed and resuspension of nearly spherical and irregular shaped particles with rough surfaces from substrates under turbulent flow condition was studied. Following our earlier approach, compact irregular shaped particles were modeled as spherical particles with a number of hemispherical bumps. It was assumed that the bump surfaces also have fine roughness. The extended Johnson-Kendall-Roberts (JKR) adhesion theory for rough surfaces was used to model the particle adhesion and detachment. A number of assumptions were made to apply the model. It was assumed that the particles have a Gaussian size distribution. The number of bumps of the irregular particles and surface roughness values of particle are assumed to be random, respectively, with Poisson and log-normal distributions. For particle detachment from the surface, the theory of critical moment was used. The effects of particle size, turbulent flow, particle irregularity and surface roughness on particle detachment and resuspension were studied for different cases. The Monte Carlo model predictions show probabilistic distributions of the particle resuspension. The simulation results are compared with the available experimental data and good agreement was found. The study provided information on the random nature of particle resuspension due to the randomness in the airflow, particle size distribution and surface roughness.

scholarly journals Monte Carlo simulation of coagulation in discrete particle-size distributions. Part 2. Interparticle forces and the quasi-stationary equilibrium hypothesis

1984 ◽  
Vol 143 ◽  
pp. 387-411 ◽  
Author(s):  
I. A. Valioulis ◽  
E. J. List ◽  
H. J. Pearson
Keyword(s):  
Monte Carlo Simulation ◽  
Particle Size ◽  
Monte Carlo ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Dimensional Analysis ◽  
Spherical Particles ◽  
Size Distributions ◽  
Particle Size Distributions ◽  
Coagulation Rate

Hunt (1982) and Friedlander (1960a, b) used dimensional analysis to derive expressions for the steady-state particle-size distribution in aerosols and hydrosols. Their results were supported by the Monte Carlo simulation of a non-interacting coagulating population of suspended spherical particles developed by Pearson, Valioulis & List (1984). Here the realism of the Monte Carlo simulation is improved by accounting for the modification to the coagulation rate caused by van der Waals', electrostatic and hydrodynamic forces acting between particles. The results indicate that the major hypothesis underlying the dimensional reasoning, that is, collisions between particles of similar size are most important in determining the shape of the particle size distribution, is valid only for shear-induced coagulation. It is shown that dimensional analysis cannot, in general, be used to predict equilibrium particle-size distributions, mainly because of the strong dependence of the interparticle force on the absolute and relative size of the interacting particles.

scholarly journals Monte Carlo simulation for soot dynamics

2012 ◽  
Vol 16 (5) ◽  
pp. 1391-1394 ◽  
Author(s):  
Kun Zhou
Keyword(s):  
Particle Size ◽  
Monte Carlo ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Gas Phase ◽  
Volume Fraction ◽  
Soot Formation ◽  
Bimodal Distribution ◽  
Number Density ◽  
Stochastic Error

A new Monte Carlo method termed Comb-like frame Monte Carlo is developed to simulate the soot dynamics. Detailed stochastic error analysis is provided. Comb-like frame Monte Carlo is coupled with the gas phase solver Chemkin II to simulate soot formation in a 1-D premixed burner stabilized flame. The simulated soot number density, volume fraction, and particle size distribution all agree well with the measurement available in literature. The origin of the bimodal distribution of particle size distribution is revealed with quantitative proof.

scholarly journals Formulation, characterization and evaluation of nanoparticles based dry powder insufflation containing terbutaline sulphate and itraconazole for the treatment of asthma

2020 ◽  
Vol 11 (1) ◽  
pp. 567-580
Author(s):  
Venugopalaiah Penabaka ◽  
Kumar B ◽  
Prasad N.B.L
Keyword(s):  
Particle Size ◽  
Size Distribution ◽  
Bronchial Asthma ◽  
Spherical Particles ◽  
Dry Powder ◽  
Terbutaline Sulphate ◽  
Release Studies ◽  
Physical Mixing ◽  
Spray Dried

Many factors affect the pulmonary drug delivery and stability of the nanoparticles an acupuncture consisting of bronchial asthma. Present research envisages on the development of dry powder nanoparticles as insufflation a acupuncture consisting of bronchial asthma (allergy due to Aspergillus fumigatus) using physical mixing and spray drying. Different founding are prepared and characterized with suitable excipients like lactose and trehalose. The particle size distribution of nano milled and spray-dried particles of Terbutaline Sulphate and Itraconazole showed unimodal size distribution. The formulations prepared with trehalose as the carrier showed less Dv90, Dv50 and Dv10 values due to the fineness in the particles of trehalose when compared to lactose. The Dv50  and Dv10 values were in the range of mountains of 0.43-0.89 µm and 0.21–0.49 µm for all formulations, which shows the primary particle size in the nanometer scale. Smooth and nearly spherical particles were produced for spray-dried formulations when compared to milled formulations. Zeta potential comes across until be between +17±0.13 to +32±0.12, which explains the particles as moderately stable. MMAD values ranges from 3.19 µm to 4.78 µm for milled nanoparticles and 3.45 µm to 4.21 µm for spray-dried particles. Formulated nanoparticles exhibited good spreading properties, which will allow all the particles to deposition palmy profusion territories consisting of the lung. In-vitro drug release studies explains that spray-dried formulations of Terbutaline sulpahte and Itraconazole using lactose as excipients released the drug upto 98.9% and 99.1% in 180mts.

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.

Particle detachment due to wheel rotation

2020 ◽  
pp. 1420326X2093516
Author(s):  
Jinwei Song ◽  
Hua Qian ◽  
Xiaohong Zheng
Keyword(s):  
Surface Roughness ◽  
Silicon Dioxide ◽  
Adhesion Force ◽  
Aluminium Oxide ◽  
Theoretical Models ◽  
Wheel Speed ◽  
Spherical Particles ◽  
Wheel Surface ◽  
Particle Detachment ◽  
Oxide Particles

Particle detachment induced by a rotating wheel was investigated theoretically and experimentally. The developed theoretical models were used to reveal how the particle detaches from a wheel surface to the surrounding air. The corresponding experiments were carried out to validate proposed models. Two groups of spherical particles were considered, i.e. silicon dioxide and aluminium oxide particles. Different forces and force moments acting on individual particles were analysed. The criteria for the rolling detachment of particles were considered. The detachment diameters under various conditions were calculated. The results show that the particle detachment was dominated by the removal and resistant forces acting on particles, including the gravity force, adhesion force, hydrodynamic force and centrifugal force. Different relevant parameters can affect particle detachment through these forces, including surface roughness, wheel speed, particle size and properties. A higher wheel speed, larger particle sizes and higher wheel surface roughness were shown to have a conducive influence on particle detachment. The resistant and removal force moments could be affected by the particle properties at the same time; therefore, the detachment diameters of the aluminium oxide particles are similar to those of silicon dioxide. This study can contribute towards the estimation of particle emissions from vehicles.

scholarly journals Computer Simulation of Volume Shrinkage after Mixing Container Media Components

1993 ◽  
Vol 118 (6) ◽  
pp. 757-761 ◽  
Author(s):  
Silvia Burés ◽  
Franklin A. Pokorny ◽  
David P. Landau ◽  
Alan M. Ferrenberg
Keyword(s):  
Experimental Data ◽  
Computer Simulation ◽  
Particle Size ◽  
Monte Carlo ◽  
Particle Size Distribution ◽  
Experimental System ◽  
Fine Sand ◽  
Spherical Particles ◽  
Particle Sizes ◽  
Coarse Particles

A FORTRAN computer program was developed to simulate packing of spherical particles via a Monte Carlo procedure. Shrinkage in volume upon mixing different particle sizes was studied and simulated results were compared with experimental data. Maximum experimental shrinkage was obtained when the proportion of coarse particles of pine bark and sand mixtures ranged from 50% to 70% of the volume. Experimental shrinkage of a mixture of coarse and fine sand was closely reproduced by means of simulation. Particle size distribution appears to be the most important factor in relation to shrinkage and also in the establishment of relationships between the simulated and the experimental system.

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