Effects of soluble surfactant on lateral migration of a bubble in a pressure driven channel flow

2020 ◽  
Vol 126 ◽  
pp. 103251
Author(s):  
Zaheer Ahmed ◽  
Daulet Izbassarov ◽  
Jiacai Lu ◽  
Gretar Tryggvason ◽  
Metin Muradoglu ◽  
...  
Keyword(s):  
Channel Flow ◽  
Lateral Migration ◽  
Soluble Surfactant ◽  
Pressure Driven

Lateral Migration of Large and Small Droplets Suspended in Channel Flow

2013 ◽  
Author(s):  
Masato Makino ◽  
Masako Sugihara-Seki
Keyword(s):  
Numerical Simulation ◽  
Channel Flow ◽  
Poiseuille Flow ◽  
Size Difference ◽  
Two Dimensional ◽  
Lateral Migration ◽  
Plane Poiseuille Flow ◽  
Surface Tensions ◽  
Segregation Behavior ◽  
The Mean

In order to investigate the effect of the size differences between suspended particles on the segregation behavior in channel flow of multicomponent suspensions, we conduct a two-dimensional numerical simulation for suspensions of fluid droplets of two different sizes subjected to a plane Poiseuille flow. The large and small droplets are assumed to have equal surface tensions and equal internal viscosities. The temporal evolutions of the lateral positions of the large and small droplets relative to the channel centerline are computed for various size ratios and area ratios of the large and small droplets. It is found that the small droplets tend to migrate toward the channel walls with increasing fraction of the large droplets and that the mean lateral positions of the large droplets are always closer to the channel centerline compared to the mean lateral positions of the small droplets, which represent the margination of the small droplets and the segregation of the droplets caused by the size difference. These trends are enhanced as the size ratio of large and small droplets is increased.

Dispersion of a buoyant plume in a turbulent pressure-driven channel flow

2009 ◽  
Vol 52 (7-8) ◽  
pp. 1827-1842 ◽  
Author(s):  
Alexandre Fabregat ◽  
Jordi Pallarès ◽  
Ildefonso Cuesta ◽  
Francesc Xavier Grau
Keyword(s):  
Channel Flow ◽  
Buoyant Plume ◽  
Turbulent Pressure ◽  
Pressure Driven

Finite Element Analysis of the Lift on a Slightly Deformable and Freely Rotating and Translating Cylinder in Two-Dimensional Channel Flow

1999 ◽  
Vol 121 (2) ◽  
pp. 148-152 ◽  
Author(s):  
Y. Zhao ◽  
M. K. Sharp
Keyword(s):  
Finite Element ◽  
Flow Field ◽  
Channel Flow ◽  
Experimental Studies ◽  
Angular Speed ◽  
Two Dimensional ◽  
Lateral Migration ◽  
Flexible Cylinder ◽  
Element Analysis ◽  
Maximum Deformation

Motivated by the lateral migration phenomena of fresh and glutaraldehyde-fixed red blood cells in a field flow fractionation (FFF) separation system, we studied the transverse hydrodynamic lift on a slightly flexible cylinder in a two-dimensional channel flow. The finite element method was used to analyze the flow field with the cylinder at different transverse locations in the channel. The shape of the cylinder was determined by the pressure on the surface of the cylinder from the flow field solution and by the internal elastic stress. The cylinder deformation and the flow field were solved simultaneously. The transverse lift exerted on the cylinder was then calculated. The axial and angular speed of the cylinder were iterated such that the drag and torque on the cylinder were nulled to represent a freely translating and rotating state. The results showed that the transverse lift on a deformable cylinder increased greatly and the equilibrium position moved closer to the center of the channel compared to a rigid cylinder. Also, with the same elastic modulus but a higher flow rate, a larger deformation and higher equilibrium location were found. The maximum deformation of the cylinder occurred when the cylinder was closest to the wall where a larger shear rate existed. The numerical results and experimental studies are discussed.

Effect of Electrical Double Layer on Electrical Conductivity and Pressure Drop in Pressure-Driven Micro-Channel Flow

2006 ◽  
Author(s):  
Bochuan Lin ◽  
Heng Ban
Keyword(s):  
Electrical Conductivity ◽  
Pressure Drop ◽  
Channel Flow ◽  
Double Layer ◽  
Electrical Double Layer ◽  
Debye Length ◽  
Channel Width ◽  
Micro Channel ◽  
Order Of Magnitude ◽  
Pressure Driven

The effect of electrical double layer (EDL) on micro-channel flow has been studied widely. Most research focused on flows with typical channel width or pipe diameter much greater than the thickness of EDL (Debye length). In such cases, the influence of EDL on the overall electrical conductivity is small, and a constant bulk electrical conductivity is often used in calculations. In our study of pressure-driven micropipette injection flow, the pipe size is on the same order of magnitude as the Debye length. To elucidate the effect of overlapping EDL the flow inside a micro-channel was analyzed. The governing equations for the flow, the Poisson equation for the electric potential, and the charge continuity equation for the net charge were solved analytically. The effect of overlapping EDL on the electrical conductivity and velocity distribution in the micro-channel and the pressure drop were quantified. The results showed that, the average conductivity of electrolyte solution inside the channel increased significantly, dependent on the channel width. With the modified mean electrical conductivity, the pressure drop for the pressure-driven flow was smaller than that without considering the influence of EDL on conductivity.

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