Related Experiment Video
Updated: Jun 23, 2026
09:45
Separating Beads and Cells in Multi-channel Microfluidic Devices Using Dielectrophoresis and Laminar Flow
Published on: February 4, 2011
A generalized theoretical model for "continuous particle separation in a microchannel having asymmetrically arranged
Karsten B Andersen1, Simon Levinsen, Winnie E Svendsen
1Department of Micro - and Nanotechnology, Technical University of Denmark, DTU Nanotech, building 345 East, DK-2800, Kongens Lyngby, Denmark.
Lab on a Chip
|May 22, 2009
Summary
This study introduces a new theoretical model for pinched flow fractionation (PFF) that accurately predicts particle separation from first principles. The model accounts for microchannel height, improving predictions without correction factors.
Area of Science:
- Microfluidics
- Particle Separation Technology
- Theoretical Modeling
Background:
- Existing theoretical models for pinched flow fractionation (PFF) often require correction factors for accurate particle separation prediction.
- The influence of finite microfluidic channel height has been underrepresented in previous PFF models.
Purpose of the Study:
- To develop a generalized theoretical model for continuous particle separation using PFF.
- To predict particle separation from first principles, eliminating the need for empirical correction factors.
- To investigate the impact of finite microchannel height on PFF system behavior.
Main Methods:
- Development of a generalized theoretical framework for pinched flow fractionation.
- Incorporation of finite microfluidic channel height into the theoretical model.
- Validation of the model against experimental data from Seki et al. (Lab Chip, 2005).
Main Results:
- The presented model successfully predicts particle separation using PFF from first principles.
- The model demonstrates the significance of considering finite microchannel height for accurate system behavior prediction.
- Model predictions show good agreement with experimental results.
Conclusions:
- The generalized theoretical model offers a more accurate and fundamental approach to understanding and predicting particle separation in PFF.
- Accounting for microchannel geometry is crucial for robust theoretical descriptions of PFF systems.
- This work advances the predictive capabilities of PFF technology for continuous particle separation.
Related Concept Videos
01:30Bernoulli's Equation for Flow Along a Streamline
Bernoulli's equation relates the energy conservation in a fluid moving along a streamline. The equation applies to incompressible and inviscid fluids under steady flow. For such a flow, Newton's second law is applied to a small fluid element, which experiences forces due to pressure differences, gravity, and velocity variations. The force balance leads to the following form of Bernoulli's equation:
01:17Steady, Laminar Flow Between Parallel Plates
Understanding steady, laminar flow between parallel plates is essential for analyzing and designing flow in narrow rectangular channels, commonly found in various water conveyance and drainage systems. The Navier-Stokes equations govern fluid motion and are generally challenging to solve due to their nonlinearity. However, simplifications are possible in certain cases, like the steady laminar flow between parallel plates. For this scenario, we assume steady, incompressible, laminar flow.
01:23Steady, Laminar Flow in Circular Tubes
Hagen-Poiseuille flow describes a viscous fluid's steady, incompressible flow through a cylindrical tube with a constant radius R. This flow profile is often applied to understand fluid transport in narrow channels, such as capillaries. It serves as a foundational example of laminar flow. In this model, cylindrical coordinates (r,θ,z) are used to describe the radial (r), angular (θ), and axial (z) dimensions within the tube. For Hagen-Poiseuille flow, the velocity profile is purely axial,...
01:30Typical Model Studies
Fluid mechanics model studies often utilize scaled-down systems to predict fluid behavior in full-scale environments, such as river flows, dam spillways, and structures interacting with open surfaces. Maintaining Froude number similarity in river models is crucial, as it replicates surface flow features like wave patterns and velocities.
01:16Bernoulli's Equation for Flow Normal to a Streamline
Bernoulli's equation for flow normal to a streamline explains how pressure varies across curved streamlines due to the outward centrifugal forces induced by the fluid's curvature. The pressure is higher on the inner side of the curve, near the center of curvature, and decreases outward to balance these centrifugal forces.
The pressure difference depends on the fluid's velocity and radius of curvature. The pressure variation is minimal in flows with nearly straight streamlines. However, the...
The pressure difference depends on the fluid's velocity and radius of curvature. The pressure variation is minimal in flows with nearly straight streamlines. However, the...
01:18Uniform Depth Channel Flow: Problem Solving
To calculate the flow rate for a trapezoidal channel, first, identify the bottom width, side slope, and flow depth of the channel. The cross-sectional area (A) corresponding to the depth of flow (y), channel bottom width (B), and side slope (θ) is determined by:Next, calculate the wetted perimeter, which includes the bottom width and the sloped side lengths in contact with the water. Using the values of the cross-sectional area and the wetted perimeter, determine the hydraulic radius by...