Suspension Of Particles In Flow Research Articles

Clogging Behavior in Abrupt Contraction Flow of Particle Suspension

Clogging Behavior in Abrupt Contraction Flow of Particle Suspension

Dimensionless Regime Mapping and Modeling for Particle Suspension Flows

Dimensionless Regime Mapping and Modeling for Particle Suspension Flows

Simulation of slurry/clean fluid boundary dispersion during placement of particulate suspension into a fracture

AbstractThe main objective of this work is to understand the major peculiarities of the process of clean fracturing fluid being displaced by a flow of particulate suspension (slurry) in a fracture channel. A number of 2D and 3D numerical simulations (based on an Euler‐Euler type model) of slurry flows in channels of complex geometry are carried out. The performance of the model is validated against experimental data by Gillies et al. Euler‐Euler simulations of a laminar slurry flow in a horizontal pipeline showed good agreement between computed and measured particle concentration distributions across a pipe. Numerical studies of slurry flows in 2D and 3D channels show the formation of an M‐shape profile of the solid phase across a channel at the initial fracture section. Our computations demonstrate the rapid growth of a dispersion zone separating a slurry and a clean fluid. It is shown that the dispersion zone is shorter in a tortuous channel than in a straight one. The computations illustrate a reduction in the dispersion zone length with an increase in the fracturing fluid viscosity. The results obtained show the importance of taking into account the previously ignored process of slurry/clean fluid boundary dispersion in prospective hydraulic fracturing simulators.

Slip Effects on MHD Convective Two-Phase Particulate Suspension Flow in a Convergent Channel

In this article an attempt has been made to dscuss the velocity and temperature slip effects on MHD convective two phase particulate suspension flow in a convergent channel with viscous dissipation .The non dimensionalised governing equations are solved using Runge-Kutta shooting method.The results obtained are represented graphically for various emerging parameters.The skin friction coefficient and Nusselt number are obtained and validated with existing results.It is found that with an increase in velocity slip parameter the velocity of the fluid increases.The fluid phase temperature decreases with an increase in temperature slip parameter.

Heat transfer analysis of Casson dusty fluid flow along a vertical wavy cone with radiating surface

A boundary layer analysis is presented to analyze the effect of non-linear surface radiation on Casson-dusty particulate suspension flow past a vertical wavy cone. Stefan-Boltzmann law is employed in the boundary conditions to express the contribution of surface radiative heat flux. Appropriate sets of transformations are used to convert the governing equations into non-dimensional, non-conserved form and then numerical scheme is applied to obtain the solutions. Our numerical results are shown graphically under the variation of important non-dimensional parameters. Comparison is also established with the available literature and it is observed that our results are in good agreement. From this study it is noticed that amplitude of the wavy cone, a, and half-angle of the cone, ϕ, increase the rate of heat transfer. Furthermore, large values of Casson rheological parameter β results in considerable enchantment in fluid velocity but an opposite behavior is noticed on temperature profiles.

Three‐dimensional numerical simulation of upflow bubbling fluidized bed in opaque tube under high flux solar heating

Solid particles can be used as a heat transfer medium in concentrated solar power plants to operate at higher temperature and achieve higher heat conversion efficiency than using the current solar heat transfer fluids that only work below 600°C. Among various particle circulation concepts, the dense particle suspension (DPS) flow in tubes, also called upflow bubbling fluidized bed (UBFB), was studied in the frame of the CSP2 FP7 European project. The DPS capacity to extract heat from a tube absorber exposed to concentrated solar radiation was demonstrated and the first values of the tube wall‐to‐DPS heat transfer coefficient were measured. A stable outlet temperature of 750°C was reached with a metallic tube, and a particle reflux in the near tube wall region was evidenced. In this article, the UBFB behavior is studied using the multiphase flow code NEPTUNE_CFD. Hydrodynamics of SiC Geldart A‐type particles and heat transfer imposed by a thermal flux at the wall are coupled in two‐dimensional unsteady numerical simulations. The convective/diffusive heat transfer between the gas and dispersed phase, and the inter‐particle radiative transfer (Rosseland approximation) are accounted for. Simulations and experiments are compared here and the temperature influence on the DPS flow is analyzed. © 2018 American Institute of Chemical Engineers AIChE J, 64: 3857–3867, 2018

Non-Linear Radiation and Chemical Reaction Impacts on Hydromagnetic Particle Suspension Flow in Non-Newtonian Fluids

Abstract A two dimensional (2D) boundary layer two-phase MHD (magneto hydrodynamics) flow of Maxwell and Oldroyd-B fluid over a stretching sheet has been explored. Heat and mass transfer phenomena is inspected through Non-linear radiation, viscous dissipation, joule heating, Soret (thermo-diffusion) and Dufour (diffusion-thermo) Impact. The boundary layer governing differential equations are modelled and transformed to a system of ODE’S with the aid of similarity transformations. The final controlled equations along boundary restrictions are resolved numerically by Runge-Kutta Felhberg method. The graphical analysis has been emphasized for the fluid and dust phase velocity, temperature and concentration fields to the influence of sundry dynamical flow quantities. Furthermore, for authentication of the present computation, the achieved results are distinguished with earlier research works in specific cases and marvellous agreement has been noted. The outcomes conveyed here manifest that velocity and boundary layer thickness escalate with boost up the values of ${K_1}$ . Velocity and boundary layer thickness declines with boost up the values of $M$ . Opposite trend is seen in temperature and concentration profiles. The specific heat ratio parameter $\gamma$ enhances the temperature profile declines. Boost up the values of Soret number $Sr$ temperature profile declines and concentration profile enhances. Skin friction factor declines with increasing values $\beta _v$ verses $M$ .

A Study on Particle Suspension Flow and Permeability Impairment in Porous Media Using LBM–DEM–IMB Simulation Method

The paper studies the particle retention and permeability impairment in porous media. This problem results from the re-injection of produced groundwater during oil production into the oilfields in order to reduce environmental damage. The lattice Boltzmann method (LBM) is used to simulate the fluid flow. The discrete element method (DEM) is adopted to simulate the particle motion. The fluid–solid interactions are simulated using the immersed moving boundary method (IMB). Based on the coupling LBM–DEM–IMB method, the paper studies the effect of particle diameter, flow rate, particle volume fraction and injection amount on the particle retention and permeability impairment. Results indicate that larger particle diameter, lower flow rate, higher volume fraction and more particle injection lead to more severe permeability impairment. In order to further study the effect of particle suspensions on heterogeneous reservoirs, a two-channel model with different permeabilities is established. The simulations show that smaller particles tend to retain in the low permeable channel and its permeability impairment is more severe. On the contrary, larger particles can reduce the permeability of high permeable channel, but they can protect the permeability of low permeable channel due to the mechanism of membrane filtration. Therefore, the sweep efficiency and oil recovery of the heterogeneous reservoirs can be improved by re-injecting produced groundwater after reasonable pretreatment. The re-injection also reduces environmental damage resulting from the large amounts of produced water in petroleum engineering. This paper provides some references for general studies on the flow of particle suspension in porous media.

Magnetohydrodynamic squeezing two-phase flow of particulate suspension in a rotating channel with transpiration cooling

This article addresses the time-dependent two-phase magnetohydrodynamic squeezing flow of dusty liquid. The fluid flow is considered in a rotating channel. The flow is constructed by squeezing of an upper plate and stretching of the lower plate and relevant equations are obtained. Numerical results are computed by utilizing shooting method along with the RK–Fehlberg scheme. The obtained solutions are validated by comparison with the existing analytical solutions. The effects of pertinent parameters on velocities of both phases are comprehensively discussed through graphical results. The numerical values of shear stress of both phases at lower and upper walls are also tabulated. Furthermore, the slope of the linear regression line through data points is determined in order to quantify the increase/decrease. Numerical simulations disclosed that the normal and transverse velocities are decreased due to stronger Coriolis force. It is also established that the velocities of the fluid phase are higher than that of the dust phase

Slot coating flow of particle suspensions: Particle migration in shear sensitive liquids

The functionality of several coated products, such as anti-reflection films and flexible electronics, depends on the complex microstructure of the deposited liquid layer. In many of these applications, the coating liquid is a particle suspension composed by small, solid particles suspended in a viscous liquid medium. Particle suspensions are classified as non-Newtonian fluids, especially at high concentrations. The non-Newtonian behavior of the coating liquid strongly affects the inner structure of the deposited liquid layer and the operability limits of slot coating processes. In this work, we study particle migration and the low-flow limit in slot coating flows of particle suspensions. Both shear rate sensitive and non shear rate sensitive suspensions are considered, and shear-induced particle migration is described by the Diffusive Flux Model. The conservation equations are solved together with the elliptic mesh-generation method to compute the position of the free surfaces using a stabilized Finite Element Method. The results show how particle migration and the rheology of the coating liquid affect the final particle distribution on the deposited liquid film and the process limits in a typical slot coating flow.

Shear-induced particle migration in the flow of particle suspensions through a sudden plane expansion

This work investigates the creeping flow of particle suspensions through an abrupt 1:4 plane expansion. The suspension is composed by non-Brownian, rigid spherical particles suspended in a viscous Newtonian liquid. The flow is described by mass and momentum conservation equations together with a convection–diffusion transport equation that accounts for shear-induced particle migration according to the diffusive flux model. The resulting set of fully coupled, nonlinear differential equations is solved with a stabilized finite element method. A detailed parametric study is presented in terms of suspension bulk concentration, particle Peclet number and ratio of diffusivity coefficients, and the numerical results show significant effects of these parameters on the particle concentration field in the flow.

Steady viscoelastic flow around high-aspect-ratio, low-blockage-ratio microfluidic cylinders

We employ a state-of-the-art microfabrication technique (selective laser-induced etching, SLE) to produce microfluidic cylinder geometries that explore new geometrical regimes. Using SLE, two microchannels are fabricated in monolithic fused silica substrate with height H=2 mm and width W=0.4 mm (aspect ratio α=H/W=5) containing cylinders of radius r=0.02 mm (blockage ratio β=2r/W=0.1), centered at the channel mid-width, W/2. An ‘sc’ channel contains a single cylinder, while a ‘dc’ channel contains two axially-aligned cylinders separated by a distance L=1 mm (L=50r). Compared with cylinder geometries fabricated by soft lithography (which typically have α ≪ 1 and β ≳ 0.5), these rigid glass devices provide a quasi-two-dimensional flow along the direction of the cylinder axis and also more clearly reveal the effects of the strong extensional wake regions located at the leading and trailing stagnation points. Using flow velocimetry and quantitative birefringence measurement techniques, we study the behaviour of a well-characterized viscoelastic polymer solution in flow around the cylinders. The small cylinder radii result in low inertia and very high elasticity numbers El ≈ 2400. For the sc device, we report strong flow modification effects around the cylinder as the flow rate is incremented. This is associated with the deformation of polymer molecules primarily in the upstream wake region, leading to the onset of a purely elastic flow asymmetry upstream of the cylinder. Stretched polymer molecules are advected around the cylinder and relax downstream of the cylinder, resulting in an extremely long elastic wake extending for > 300r downstream. In the dc channel, at lower flow rates, similar flow modification effects are observed to develop around, and downstream of, both cylinders. However, at higher flow rates the wake of the first cylinder extends > 50r downstream, and begins to interact with the second cylinder. The second cylinder becomes encapsulated by the wake of the first and is effectively obviated from the flow field. The results will be of relevance to understanding practical applications of viscoelastic fluids, for example in particle suspension and porous media flows, and also for benchmarking against numerical simulations using viscoelastic constitutive models.

Radiative heat transfer analysis of non-Newtonian dusty Casson fluid flow along a complex wavy surface

ABSTRACTIn this article, numerical solutions are obtained to observe the influence of thermal radiation on Casson particulate suspension flow past a complex isothermal wavy surface. Rosseland diffusion approximation is employed to express the contribution of radiative heat flux over the Casson fluid model. Using coordinate transformations, the two-phase model is converted into a suitable form and then integrated numerically by employing implicit finite-difference method. The numerical results are discussed in detail in terms of shear stress, rate of heat transfer, streamlines, and isotherms. It is found that the rate of heat transfer increases extensively when radiation parameter and mass concentration parameter are penetrated into the mechanism.

Second-order accurate immersed boundary-discrete unified gas kinetic scheme for fluid-particle flows

An immersed boundary-discrete unified gas kinetic scheme (IB-DUGKS) is developed in this paper for interface-resolved simulation of particle suspension flows. Compared with the conventional IB methods which consider the interface as a generator of external force, the no-slip boundary condition in the present scheme is implemented directly by correcting the distribution functions near the interface. Therefore, it makes good use of the intrinsic nature for the DUGKS as a kinetic method, and removes simultaneously the necessity to construct the models to evaluate and adsorb the external force in DUGKS. Furthermore, the present IB-DUGKS promotes the accuracy of the IB methods from first- to second-order, which is verified reasonably in the cylindrical Couette flow. After that, several well-established particle-fluid flows are simulated, including the motion of a neutrally buoyancy particle moving in the Poiseuille and Couette flows, and sedimentation of a particle in an enclosure. In all test cases, the results are in good agreement with the data available in the literature. The robust of the present IB-DUGKS is also demonstrated in the simulations.

Vortex behavior of particle suspension flow in a wedge for the second-order fluid

Effect of Weissenberg number, Reynolds number, Stokes number and wedge angle on the vortex behavior of particle suspension flow is investigated numerically in a wedge for the second-order viscoelastic fluid. The results show that there exist symmetrical vortices near the walls close to apex for different wedge angles, and the vortex length is inversely proportional to the wedge angle. Increase of the Reynolds number not only increases the vortex length but also their dependence on the Weissenberg number. The vortex length increases with the increase of Weissenberg number and finally reaches an asymptotic value. The vortex gradually developed as the Stokes number is decreased, and the vortex length has a maximum for the single phase flow. The presence of particles will suppress the development of vortex, and the suppression degree is directly proportional to the Stokes number. The Reynolds number has a larger impact on the vortex length than the wedge angle in the parameter region studied here.

Direct Numerical Simulation of Cellular-Scale Blood Flow in 3D Microvascular Networks

We present, to our knowledge, the first direct numerical simulation of 3D cellular-scale blood flow in physiologically realistic microvascular networks. The vascular networks are designed following in vivo images and data, and are comprised of bifurcating, merging, and winding vessels. Our model resolves the large deformation and dynamics of each individual red blood cell flowing through the networks with high fidelity, while simultaneously retaining the highly complex geometric details of the vascular architecture. To our knowledge, our simulations predict several novel and unexpected phenomena. We show that heterogeneity in hemodynamic quantities, which is a hallmark of microvascular blood flow, appears both in space and time, and that the temporal heterogeneity is more severe than its spatial counterpart. The cells are observed to frequently jam at vascular bifurcations resulting in reductions in hematocrit and flow rate in the daughter and mother vessels. We find that red blood cell jamming at vascular bifurcations results in several orders-of-magnitude increase in hemodynamic resistance, and thus provides an additional mechanism of increased in vivo blood viscosity as compared to that determined in vitro. A striking result from our simulations is negative pressure-flow correlations observed in several vessels, implying a significant deviation from Poiseuille’s law. Furthermore, negative correlations between vascular resistance and hematocrit are observed in various vessels, also defying a major principle of particulate suspension flow. To our knowledge, these novel findings are absent in blood flow in straight tubes, and they underscore the importance of considering realistic physiological geometry and resolved cellular interactions in modeling microvascular hemodynamics.

Sedimentation and Marangoni stress in slot coating flow of particle suspension

Slot coating is a common method in the manufacturing of a wide variety of functional films. In many applications, the coating liquid is a particle suspension and the performance of the final product is directly related to the micro structure of the film. Fundamental understanding of the suspension flow enables a better control of the particle distribution on the coated layer and, consequently, on the coating process and product performance optimization. A common simplified approach to study coating flow of non-colloidal particle suspension is to consider that the particles are uniformly distributed in the coating bead and that the liquid viscosity is constant and equal to the value of the bulk concentration. However, experimental evidences have shown that shear-induced migration leads to non-uniform particle distribution. The literature presents numerical predictions on surface inactive, neutrally buoyant particle suspension flow which have shown that particle distribution in the coated layer strongly depends on the process conditions. Here, we extend the previous analyses to explore the effect of different process conditions, including the effect of particle sedimentation and Marangoni stresses caused by surface-active particles. Results show how particle distribution changes with flow conditions and particle properties, and that Marangoni stresses can change the recirculation pattern of the flow.

Two-Phase Particulate Suspension Flow in Convergent and Divergent Channels: A Numerical Model

The problem dealing with the two-phase flow of particulate suspension in a converging diverging channel has been analyzed. The basic equations governing the flow are reduced to a set of ordinary differential equations by using the appropriate transformations for the velocity components. The numerical solutions are carried out using numerical technique and the results are presented graphically. The flow phenomena have been analyzed for different physical parameters, Reynolds number, cross flow Reynolds number, angle of the channel, ratios of densities fluid and particle phases and momentum inverse stokes number. The effects of parameters on the velocity of the fluid and the skin friction has been discussed.

Boundary Layer Flow and Heat Transfer of fluid particle suspension with nanoparticles over a nonlinear stretching sheet embedded in a porous medium

AbstractAn analysis has been carried out to study the effect of nonlinear thermal radiation on slip flow and heat transfer of fluid particle suspension with nanoparticles over a nonlinear stretching sheet immersed in a porous medium. Water is considered as a base fluid with dust particles along with suspended Aluminum Oxide (Al

Unsteady Boundary Layer Flow and Convective Heat Transfer of a Fluid Particle Suspension with Nanoparticles over a Stretching Surface

AbstractWe analyzed the effects of Biot number and non-uniform heat source/sink on boundary layer flow and nonlinear radiative heat transfer of fluid particle suspension over an unsteady stretching surface embedded in a porous medium with nanoparticles. We considered conducting dust particles embedded with -water nanopartcles. The governing equations are transformed into nonlinear ordinary differential equations by using local similarity transformations and solved numerically using Runge–Kutta-Fehlberg-45 order method along with shooting technique. The effects of non-dimensional parameters on velocity and temperature profiles for fluid phase and dust phase are discussed and presented through graphs. Also, friction factor and Nusselt number are discussed and presented through graphs. Comparisons of the present study were made with existing studies under some special assumptions. The present results have an excellent agreement with existing studies. Results indicated that the enhancement in fluid particle interaction parameter increases the heat transfer rate and depreciates the wall friction. Also, radiation parameter has the tendency to increase the temperature profiles of the dusty nanofluid.