Investigation of Particles Statistics in large Eddy Simulated Turbulent Channel Flow using Generalized lattice Boltzmann Method

The interaction of spherical solid particles with turbulent eddies in a 3-D turbulent channel flow with friction Reynolds number was studied. A generalized lattice Boltzmann equation (GLBE) was used for computation of instantaneous turbulent flow field for which large eddy simulation (LES) was employed. The sub-grid-scale (SGS) turbulence effects were simulated through a shear-improved Smagorinsky model (SISM), which can predict turbulent near wall region without any wall function. Statistical properties of particles behavior such as root mean square (RMS) velocities were studied as a function of dimensionless particle relaxation time ( ) by using a Lagrangian approach. Combination of SISM in GLBE with particle tracking analysis in turbulent channel flow is novelty of the present work. Both GLBE and SISM solve the flow field equations locally. This is an advantage of this method and makes it easy implementing. Comparison of the present results with previous available data indicated that SISM in GLBE is a reliable method for simulation of turbulent flows which is a key point to predict particles behavior correctly

Ionic strength and zeta potential effects on colloid transport and retention processes: Ionic strength and zeta potential effects on colloid transport and retention processes

In this study, a fully coupled pore scale model was developed with the aim of exploring the effects of ionic strength and zeta potential on colloids transport under favourable and unfavourable conditions. The Lattice Boltzmann-Smoothed Profile method was used to simulate particle-particle and particle-fluid interactions without a need for assumptions of dilute suspension and clean bed filtration. Simulation using a wide range of parameters have shown creation, and breakup of agglomerates. Results are used to obtain time-averaged behaviour of transport properties, such as pore void fraction, conductivity, and surface coverage. We have found that in comparison with zeta potential, increasing ionic strength had a greater impact on particles behaviour. A raise in ionic strength caused a decrease in pore void fraction and its conductivity and an increase in aggregates connectivity

Direct pore scale numerical simulation of colloid transport and retention. Part I: Fluid flow velocity, colloid size, and pore structure effects

In this study, we have developed a combined lattice Boltzmann-smoothed profile method to explore coupled mechanisms governing transport of colloids and their retention in porous media. We have considered flow in a constricted tube and included hydrodynamic, gravity, buoyancy, van der Waals and electrostatic forces to simulate colloid transport and aggregation. A major advantage of this complete formulation is that it does not require any common assumptions which neglect the effects of inter-particle forces (e.g., dilute suspension, or clean bed filtration), and pore structure changes due to colloid retention. The results show an increase in colloid aggregation and surface coverage as pore velocity decreases. However, the pore void fraction and its conductivity show a reduction with decreased velocity. In the presence of a secondary energy minimum, rolling of colloids on the grain surface is demonstrated to be the major mechanism that prevents pore clogging. Details of these observations are provided and a comprehensive sensitivity analysis of model parameters is performed and discussed

Ionic strength and zeta potential effects on colloid transport and retention processes: Ionic strength and zeta potential effects on colloid transport and retention processes

In this study, a fully coupled pore scale model was developed with the aim of exploring the effects of ionic strength and zeta potential on colloids transport under favourable and unfavourable conditions. The Lattice Boltzmann-Smoothed Profile method was used to simulate particle-particle and particle-fluid interactions without a need for assumptions of dilute suspension and clean bed filtration. Simulation using a wide range of parameters have shown creation, and breakup of agglomerates. Results are used to obtain time-averaged behaviour of transport properties, such as pore void fraction, conductivity, and surface coverage. We have found that in comparison with zeta potential, increasing ionic strength had a greater impact on particles behaviour. A raise in ionic strength caused a decrease in pore void fraction and its conductivity and an increase in aggregates connectivity

Direct pore scale numerical simulation of colloid transport and retention. Part I: Fluid flow velocity, colloid size, and pore structure effects

In this study, we have developed a combined lattice Boltzmann-smoothed profile method to explore coupled mechanisms governing transport of colloids and their retention in porous media. We have considered flow in a constricted tube and included hydrodynamic, gravity, buoyancy, van der Waals and electrostatic forces to simulate colloid transport and aggregation. A major advantage of this complete formulation is that it does not require any common assumptions which neglect the effects of inter-particle forces (e.g., dilute suspension, or clean bed filtration), and pore structure changes due to colloid retention. The results show an increase in colloid aggregation and surface coverage as pore velocity decreases. However, the pore void fraction and its conductivity show a reduction with decreased velocity. In the presence of a secondary energy minimum, rolling of colloids on the grain surface is demonstrated to be the major mechanism that prevents pore clogging. Details of these observations are provided and a comprehensive sensitivity analysis of model parameters is performed and discussed