Miniature laboratories are required to efficiently analyze the information in the human DNA. One of the problems that arise in these lab-on-chip devices is in the transport of the liquid samples and other solutions in the chip, which are...
This model demonstrates how to set up a fluid-structure interaction problem in COMSOL Multiphysics. It illustrates how fluid flow can deform solid structures and how to solve for the flow in a continuously deforming geometry. The...
At the macroscopic level, systems usually mix fluids using mechanical actuators or turbulent 3D flow. At the microscale level, however, neither of these approaches is practical or even possible. This model demonstrates the mixing of...
This model presents a time-dependent study of a microchannel that is used to infuse and flush another piece of equipment with a fluid. The pressure at the five inlets varies sinusoidally as functions of time, and the velocity vector...
Microlaboratories for biochemical applications often require rapid mixing of different fluid streams. At the microscale, flow is usually highly ordered laminar flow, and the lack of turbulence makes diffusion the primary mechanism for...
This model studies the use of AC electrokinetic forces to enhance the rate of transport of electrolytic reactants to a reaction surface on the wall of a microchannel. If transport was to be governed by flow alone, then the flow...
This model presents an example of pressure driven flow and electrophoresis in a 3D micro channel system. Researchers often use a device similar to the one in this model as an electrokinetic sample injector in biochips to obtain...
This model performs a topological optimization for a Tesla microvalve. A Tesla microvalve inhibits backwards flow using friction forces rather than moving parts. The design can be optimized by distributing a specific amount of material...
This example studies a narrow vertical cylinder placed on top of a reservoir filled with water. Because of wall adhesion and surface tension at the air/water interface, water rises through the channel. Surface tension and wall adhesive...
Cemented tungsten carbides are hard metals used in steel cutting tools. They are produced by heating a powder consisting typically of tungsten carbide (WC) grains and cobalt (Co) grains. When the powder is heated, the cobalt melts but the...
Emulsions consist of small liquid droplets immersed in an immiscible liquid and widely occur in the production of food, cosmetics, fine chemicals, and pharmaceutical products. The quality of the product is typically dependent on the size...
Miniature laboratories are required to efficiently analyze the information in human DNA. Such laboratories could facilitate tailor-made diagnoses and treatment of hereditary diseases for each individual. One problem that arises in...
Micropumps, especially those based on electroosmotic flow (EOF), are essential components in microfluidic lab-on-a-chip devices, as they contain no moving parts and are relatively easy to integrate in microfluidic circuits during...
Inkjet printers are attractive tools for printing text and images because they combine low cost and high resolution with acceptable speed. Designers can vary several parameters to modify a printer’s performance. Simulations can be...
The Marangoni effect results in a slip velocity in the tangential direction on a fluid/fluid interface due to gradients in the surface tension coefficient. When the surface tension coefficient is constant, a two-fluid system may exist in...
This benchmark model shows how to set up and simulate electrocoalescence phenomena using COMSOL Multiphysics and the Chemical Engineering Module. The calculated results are compared to published experimental work. In the reported...
This model is a benchmark model for the Slip Flow interface. It is based on both analytic and numeric calculations. Air at atmospheric pressure flows through a conducting micro-channel connecting two reservoirs maintained at different...
The contact angle of a two-fluid interface with a solid surface is determined by the balance of the forces at the contact point. In electrowetting the balance of forces at the contact point is modified by the application of a voltage...
This example describes the operation of a drug delivery system that supplies a variable concentration of a water soluble drug. A droplet with a fixed volume of water travels down a capillary tube at a constant velocity. Part of the...
The catenary is the geometrical shape that corresponds to the curve followed by an idealized chain or cable supported at both ends and hanging under its own weight. The viscous catenary problem describes the motion of a cylinder of highly...
When a constant pressure difference drives flow through a narrow constriction between parallel plates (or through a cylindrical tube), the flow rate exhibits a characteristic minimum as the absolute pressure at the inlet is reduced. This...
This model simulates an H-shaped micro-cell designed for controlled diffusive mixing. The cell puts two different laminar streams in contact for a controlled period of time. The contact surface is well-defined and, by controlling the flow...
Particle Tracing is used in conjunction with magnetic fields and pressure-driven microfluidic flow to calculate the separation of red blood cells from blood plasma using magnetophoresis. An array of soft iron rectangles on either side of...
This example models a split and recombine mixer channel in which a tracer fluid is introduced and mixed by multi-lamination. Diffusion is removed from the model using an extremely low diffusion coefficient so that any numerical diffusion...
A lab-on-a-chip platform can be realized on a rotating disc by designing channels and other features to use the Coriolis or centrifugal forces to manipulate the flow. These forces are controlled by changing the angular velocity of the...
