scholarly journals The Effect of Bubbles on Particle Migration in Non-Newtonian Fluids

Separations ◽  
2021 ◽  
Vol 8 (4) ◽  
pp. 36
Author(s):  
Jie Shan ◽  
Xiaojun Zhou
Keyword(s):  
Newtonian Fluid ◽  
Theoretical Data ◽  
Liquid Interface ◽  
Newtonian Fluids ◽  
Particle Migration ◽  
Effective Control ◽  
Two Phase ◽  
Migration Ability ◽  
Starting Conditions ◽  
Separation Force

The movement of the gas–liquid interface caused by the movement of the bubble position will have an impact on the starting conditions for particle migration. This article quantifies the influence of moving bubbles on the starting conditions of particle migration in non-Newtonian fluids, and it aims to better understand the influence of bubbles moving in non-Newtonian fluids on particle migration to achieve more effective control. First, the forces and moments acting on the particles are analyzed; then, fluid dynamics, non-Newtonian fluid mechanics, extended DLVO (Derjaguin Landau Verwey Overbeek theory), surface tension, and friction are applied on the combined effects of particle migration. Then, we reasonably predict the influence of gas–liquid interface movement on particle migration in non-Newtonian fluids. The theoretical results show that the movement of the gas–liquid interface in non-Newtonian fluids will increase the separation force acting on the particles, which will lead to particle migration. Second, we carry out the particle migration experiment of moving bubbles in non-Newtonian fluid. Experiments show that when the solid–liquid two-phase flow is originally stable, particle migration occurs after the bubble movement is added. This phenomenon shows that the non-Newtonian fluid with bubble motion has stronger particle migration ability. Although there are some errors, the experimental results basically support the theoretical data.

Experimental Comparison of Newtonian and Non-Newtonian Multiphase Flow in Horizontal Pipes

2020 ◽  
Author(s):  
Faraj Ben Rajeb ◽  
Mohamed Odan ◽  
Amer Aborig ◽  
Syed Imtiaz ◽  
Yan Zhang ◽  
...  
Keyword(s):  
Newtonian Fluid ◽  
Two Phase Flow ◽  
Newtonian Fluids ◽  
Theoretical Research ◽  
Experimental Comparison ◽  
Phase Flow ◽  
Flow Loop ◽  
Two Phase ◽  
Mixture Flow ◽  
Pressure Drops

Abstract Two-phase flow of gas/Newtonian and gas/non-Newtonian fluid through pipes occurs frequently in the chemical industry as well as in petroleum refining. Extensive experimental and theoretical research has been carried out on these systems in order to better understand their behaviour under different conditions regarding pressure, temperature and mixture concentrations. In this study, experimental apparatuses are used to investigate two-phase flow of gas/liquid systems through pipes. Air is used as the gas in the experiments, while water is used as the Newtonian fluid and Xanthan gum as the non-Newtonian fluid. The objectives of the study are to compare pressure drops when the same gas flows simultaneously with Newtonian and non-Newtonian fluids through tubes. The comparison here is between experimental pressure drops and estimated pressure drops, based on available empirical correlations for gas/Newtonian and gas/non-Newtonian flow. The trend exhibited by the pressure drops in both systems helps us to better understand the relationship between mixture flow pressure drops in Newtonian and non-Newtonian fluids and thereby develop a new experimental model. The tube diameter for the flow loop is 3/4 inch and the flow type ranges from transient to turbulent.

scholarly journals Particle Focusing under Newtonian and Viscoelastic Flow in a Straight Rhombic Microchannel

Micromachines ◽  
2020 ◽  
Vol 11 (11) ◽  
pp. 998
Author(s):  
Joo-Yong Kwon ◽  
Taehoon Kim ◽  
Jungwoo Kim ◽  
Younghak Cho
Keyword(s):  
Newtonian Fluid ◽  
Microelectromechanical Systems ◽  
Viscoelastic Fluids ◽  
Newtonian Fluids ◽  
Particle Migration ◽  
Inertial Particles ◽  
Cross Sectional ◽  
Double Line ◽  
Particle Focusing ◽  
Wide Range

Particle behavior in viscoelastic fluids has attracted considerable attention in recent years. In viscoelastic fluids, as opposed to Newtonian fluids, particle focusing can be simply realized in a microchannel without any external forces or complex structures. In this study, a polydimethylsiloxane (PDMS) microchannel with a rhombic cross-sectional shape was fabricated to experimentally investigate the behavior of inertial and elasto-inertial particles. Particle migration and behavior in Newtonian and non-Newtonian fluids were compared with respect to the flow rate and particle size to investigate their effect on the particle focusing position and focusing width. The PDMS rhombic microchannel was fabricated using basic microelectromechanical systems (MEMS) processes. The experimental results showed that single-line particle focusing was formed along the centerline of the microchannel in the non-Newtonian fluid, unlike the double-line particle focusing in the Newtonian fluid over a wide range of flow rates. Numerical simulation using the same flow conditions as in the experiments revealed that the particles suspended in the channel tend to drift toward the center of the channel owing to the negative net force throughout the cross-sectional area. This supports the experimental observation that the viscoelastic fluid in the rhombic microchannel significantly influences particle migration toward the channel center without any external force owing to coupling between the inertia and elasticity.

A comparative study of MHD fluid-particle suspension induced by metachronal wave under the effects of lubricated walls

2021 ◽  
pp. 2150204
Author(s):  
Mubbashar Nazeer ◽  
Farooq Hussain ◽  
Laiba Shabbir ◽  
Adila Saleem ◽  
M. Ijaz Khan ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Magnetic Fields ◽  
Multiphase Flow ◽  
Thermal Radiation ◽  
Newtonian Fluid ◽  
Closed Form Solution ◽  
Casson Fluid ◽  
Form Solution ◽  
Phase Flow ◽  
Two Phase

In this paper, the two-phase flow of non-Newtonian fluid is investigated. The main source of the flow is metachronal waves which are caused by the back and forth motion of cilia attached to the opposite walls of the channel. Magnetohydrodynamics (MHD) of Casson fluid experience the effects of transverse magnetic fields incorporated with the slippery walls of the channel. Thermal effects are examined by taking Roseland’s approximation and application of thermal radiation into account. The heat transfer through the multiphase flow of non-Newtonian fluid is further, compared with Newtonian bi-phase flow. Since the main objective of the current study is to analyze heat transfer through an MHD multiphase flow of Casson fluid. The two-phase heated flow of non-Newtonian fluid is driven by cilia motion results in nonlinear and coupled differential equations which are transformed and subsequently, integrated subject to slip boundary conditions. A closed-form solution is eventually obtained form that effectively describes the flow dynamics of multiphase flow. A comprehensive parametric study is carried out which highlights the significant contribution of pertinent parameters of the heat transfer of Casson multiphase flow. It is inferred that lubricated walls and magnetic fields hamper the movement of multiphase flow. It is noted that a sufficient amount of additional thermal energy moves into the system, due to the Eckert number and Prandtl number. While thermal radiation acts differently by expunging the heat transfer. Moreover, Casson multiphase flow is a more suitable source of heat transfer than Newtonian multiphase flow.

Analysis of the Motion and Deformation of a Bubble Rising in a Viscoelastic Fluid

2006 ◽  
Author(s):  
Shriram Pillapakkam ◽  
Pushpendra Singh ◽  
Denis L. Blackmore ◽  
Nadine Aubry
Keyword(s):  
Velocity Field ◽  
Newtonian Fluid ◽  
Viscoelastic Fluid ◽  
Bubble Radius ◽  
Polymer Concentration ◽  
Deborah Number ◽  
Two Phase ◽  
Bubble Volume ◽  
Recirculation Zones ◽  
Bubble Rising

A finite element code based on the level set method is developed for performing two and three dimensional direct numerical simulations (DNS) of viscoelastic two-phase flow problems. The Oldroyd-B constitutive equation is used to model the viscoelastic liquid and both transient and steady state shapes of bubbles in viscoelastic buoyancy driven flows are studied. The influence of the governing dimensionless parameters, namely the Capillary number (Ca), the Deborah Number (De) and the polymer concentration parameter c, on the deformation of the bubble is also analyzed. Our simulations demonstrate that the rise velocity oscillates before reaching a steady value. The shape of the bubble, the magnitude of velocity overshoot and the amount of damping depend mainly on the parameter c and the bubble radius. Simulations also show that there is a critical bubble volume at which there is a sharp increase in the bubble terminal velocity as the increasing bubble volume increases, similar to the behavior observed in experiments. The structure of the wake of a bubble rising in a Newtonian fluid is strikingly different from that of a bubble rising in a viscoelastic fluid. In addition to the two recirculation zones at the equator of the bubble rising in a Newtonian fluid, two more recirculation zones exist in the wake of a bubble rising in viscoelastic fluids which influence the shape of a rising bubble. Interestingly, the direction of motion of the fluid a short distance below the trailing edge of a bubble rising in a viscoelastic fluid is in the opposite direction to the direction of the motion of the bubble, thus creating a “negative wake”. In this paper, the velocity field in the wake of the bubble, the effect of the parameters on the velocity field and their influence on the shape of the bubble are also investigated.

scholarly journals The dam-break problem for concentrated suspensions of neutrally buoyant particles

2013 ◽  
Vol 724 ◽  
pp. 95-122 ◽  
Author(s):  
C. Ancey ◽  
N. Andreini ◽  
G. Epely-Chauvin
Keyword(s):  
Velocity Profile ◽  
Newtonian Fluid ◽  
Velocity Profiles ◽  
Lubrication Theory ◽  
Dam Break ◽  
Particle Migration ◽  
Flow Depth ◽  
Concentrated Suspensions ◽  
Front Position ◽  
Neutrally Buoyant

AbstractThis paper addresses the dam-break problem for particle suspensions, that is, the flow of a finite volume of suspension released suddenly down an inclined flume. We were concerned with concentrated suspensions made up of neutrally buoyant non-colloidal particles within a Newtonian fluid. Experiments were conducted over wide ranges of slope, concentration and mass. The major contributions of our experimental study are the simultaneous measurement of local flow properties far from the sidewalls (velocity profile and, with lower accuracy, particle concentration) and macroscopic features (front position, flow depth profile). To that end, the refractive index of the fluid was adapted to closely match that of the particles, enabling data acquisition up to particle volume fractions of 60 %. Particle migration resulted in the blunting of the velocity profile, in contrast to the parabolic profile observed in homogeneous Newtonian fluids. The experimental results were compared with predictions from lubrication theory and particle migration theory. For solids fractions as large as 45 %, the flow behaviour did not differ much from that of a homogeneous Newtonian fluid. More specifically, we observed that the velocity profiles were closely approximated by a parabolic form and there was little evidence of particle migration throughout the depth. For particle concentrations in the 52–56 % range, the flow depth and front position were fairly well predicted by lubrication theory, but taking a closer look at the velocity profiles revealed that particle migration had noticeable effects on the shape of the velocity profile (blunting), but had little impact on its strength, which explained why lubrication theory performed well. Particle migration theories (such as the shear-induced diffusion model) successfully captured the slow evolution of the velocity profiles. For particle concentrations in excess of 56 %, the macroscopic flow features were grossly predicted by lubrication theory (to within 20 % for the flow depth, 50 % for the front position). The flows seemed to reach a steady state, i.e. the shape of the velocity profile showed little time dependence.

Influence of an inclined magnetic field on the Poiseuille flow of immiscible micropolar–Newtonian fluids in a porous medium

2018 ◽  
Vol 96 (9) ◽  
pp. 1016-1028 ◽  
Author(s):  
Pramod Kumar Yadav ◽  
Sneha Jaiswal
Keyword(s):  
Magnetic Field ◽  
Rotational Velocity ◽  
Immiscible Fluids ◽  
Newtonian Fluids ◽  
Porous Channel ◽  
Physical Parameters ◽  
Inclined Magnetic Field ◽  
Two Phase ◽  
Flow Through ◽  
Newtonian Viscous Fluid

The present problem is concerned with two-phase fluid flow through a horizontal porous channel in the presence of uniform inclined magnetic field. The micropolar fluid or Eringen fluid and Newtonian viscous fluid are flowing in the upper and lower regions of the horizontal porous channel, respectively. In this paper, the permeability of each region of the horizontal porous channel has been taken to be different. The effects of various physical parameters like angles of inclination of magnetic field, viscosity ratio, micropolarity parameter, etc., on the velocities, micro-rotational velocity of two immiscible fluids in horizontal porous channel, wall-shear stress, and flow rate have been discussed. The result obtained for immiscible micropolar–Newtonian fluids are compared with the results of two immiscible Newtonian fluids. The obtained result may be used in production of oil from oil reservoirs, purification of contaminated ground water, etc.

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