Particle dynamics in drying colloidal solution using discrete particle method

2021 ◽  
Author(s):  
Ryungeun Song ◽  
Minki Lee ◽  
Hyeokgyun Moon ◽  
Saebom Lee ◽  
Seonghun Shin ◽  
...  
Keyword(s):  
Peclet Number ◽  
Particle Concentration ◽  
Colloidal Solution ◽  
Particle Method ◽  
Particle Dynamics ◽  
Colloidal Solutions ◽  
Initial Particle ◽  
Discrete Particle ◽  
Péclet Number ◽  
Discrete Particle Method

Abstract We study particle dynamics in drying colloidal solutions using the numerical simulation with discrete particle method (DPM). Simulations of two different systems were conducted; the drying dynamics of monodispersed and binary mixture of colloidal solution, and compared with those from the previous studies. In the monodispersed colloidal solution, the time evolution of particle concentration profile for varying Péclet number was simulated with the same initial particle concentration. In the binary colloidal solution, when the particle size ratio α is 3, three different stratification modes were observed varying Péclet number and initial particle concentration. By comparison, our method was in a good agreement with the existing methods. Additionally, because of the mesh-based Eulerian approach in our model, other various multi-physical phenomena, such as effect of thermal Marangoni or chemical reaction, can be included in an easy way. From the results, we expect that this work can provide a physical insight for predicting the quality of colloidal drying in a complicated situation.

scholarly journals MODELING OF PARTICLE SIZE SEGREGATION: CALIBRATION USING THE DISCRETE PARTICLE METHOD

2012 ◽  
Vol 23 (08) ◽  
pp. 1240014 ◽  
Author(s):  
ANTHONY THORNTON ◽  
THOMAS WEINHART ◽  
STEFAN LUDING ◽  
ONNO BOKHOVE
Keyword(s):  
Particle Size ◽  
Peclet Number ◽  
Particle Method ◽  
Size Ratio ◽  
Size Segregation ◽  
Discrete Particle ◽  
Péclet Number ◽  
Particle Properties ◽  
Chute Flow ◽  
Discrete Particle Method

Over the last 25 years a lot of work has been undertaken on constructing continuum models for segregation of particles of different sizes. We focus on one model that is designed to predict segregation and remixing of two differently sized particle species. This model contains two dimensionless parameters: Sr, a measure of the segregation rate, and Dr, a measure of the strength of diffusion. These, in general, depend on both flow and particle properties and one of the weaknesses of the model is that these dependencies are not predicted. They have to be determined by either experiments or simulations. We present steady-state, periodic, chute-flow simulations using the discrete particle method (DPM) for several bi-disperse systems with different size ratios. The aim is to determine one parameter in the continuum model, i.e. the segregation Péclet number (ratio of the segregation rate to diffusion, Sr/Dr) as a function of the particle size ratio. Reasonable agreement is found; but, also measurable discrepancies are reported; mainly, in the simulations a thick pure phase of large particles is formed at the top of the flow. Additionally, it was found that the Péclet number increases linearly with the size ratio for low values, but saturates to a value of approximately 7.7.

Computer virtual experiment on fluidized beds using a coarse-grained discrete particle method—EMMS-DPM

2016 ◽  
Vol 155 ◽  
pp. 314-337 ◽  
Author(s):  
Liqiang Lu ◽  
Ji Xu ◽  
Wei Ge ◽  
Guoxian Gao ◽  
Yong Jiang ◽  
...  
Keyword(s):  
Fluidized Beds ◽  
Particle Method ◽  
Coarse Grained ◽  
Virtual Experiment ◽  
Discrete Particle ◽  
Discrete Particle Method

Simulation of Particle-Wall Collisions in a Viscous Fluid Using a Resolved Discrete Particle Method

2010 ◽  
Author(s):  
Zhi-Gang Feng ◽  
Efstathis E. Michaelides ◽  
Shaolin Mao
Keyword(s):  
Viscous Fluid ◽  
Numerical Method ◽  
Solid Wall ◽  
Particle Method ◽  
Solid Particles ◽  
Force Density ◽  
Model Parameters ◽  
Discrete Particle ◽  
Soft Sphere ◽  
Discrete Particle Method

The process of particle-wall collisions is very important in understanding and determining the fluid-particle behavior, especially near walls. Detailed information on particle-wall collisions can provide insight on the formulation of appropriate boundary conditions of the particulate phases in two-fluid models. We have developed a three-dimensional Resolved Discrete Particle Method (RDPM) that is capable of meaningfully handling particle-wall collisions in a viscous fluid. This numerical method makes use of a Finite-Difference method in combination with the Immersed Boundary (IB) method for treating the particulate phase. A regular Eulerian grid is used to solve the modified momentum equations in the entire flow region. In the region that is occupied by the solid particles, a second particle-based Lagrangian grid is used, and a force density function is introduced to represent the momentum interactions between particle and fluid. We have used this numerical method to study both the central and oblique impact of a spherical particle with a wall in a viscous fluid. The particles are allowed to move in the fluid until they collide with the solid wall. The collision force on the particle is modeled by a soft-sphere collision scheme with a linear spring-dashpot system. The hydrodynamic force on the particle is solved directly from the RDPM. By following the trajectories of a particle, we investigate the effect of the collision model parameters to the dynamics of a particle close to the wall. We report in this paper the rebound velocity of the particle, the coefficient of restitution, and the particle slip velocity at the wall when a variety of different soft-sphere collision parameters are used.

A Numerical Approach to Predict Sulphur Dioxide Emissions During Switchgrass Combustion

2013 ◽  
Vol 34 (1) ◽  
pp. 121-137
Author(s):  
Bernhard Peters ◽  
Joanna Smuła-Ostaszewska
Keyword(s):  
Experimental Data ◽  
Sulphur Dioxide ◽  
Kinetic Data ◽  
Combustion Process ◽  
Particle Method ◽  
Least Square ◽  
Exponential Factor ◽  
Discrete Particle ◽  
Sulphur Dioxide Emissions ◽  
Discrete Particle Method

Abstract The demand for a net reduction of carbon dioxide and restrictions on energy efficiency make thermal conversion of biomass a very attractive alternative for energy production. However, sulphur dioxide emissions are of major environmental concern and may lead to an increased corrosion rate of boilers in the absence of sulfatation reactions. Therefore, the objective of the present study is to evaluate the kinetics of formation of sulphur dioxide during switchgrass combustion. Experimental data that records the combustion process and the emission formation versus time, carried out by the National Renewable Energy Institute in Colorado (US), was used to evaluate the kinetic data. The combustion of switchgrass is described sufficiently accurate by the Discrete Particle Method (DPM). It predicts all major processes such as heating-up, pyrolysis, combustion of switchgrass by solving the differential conservation equations for mass and energy. The formation reactions of sulphur dioxide are approximated by an Arrhenius-like expression including a pre-exponential factor and an activation energy. Thus, the results predicted by the Discrete Particle Method were compared to measurements and the kinetic parameters were subsequently corrected by the least square method until the deviation between measurements and predictions was minimised. The determined kinetic data yielded good agreement between experimental data and predictions.

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