microfluidics – Page 15 – TechConnect Briefs

Multiscale Modeling of Microfluidics

Karniadakis G., Brown University, US

Micro-electro-mechanical systems involve complex functions governed by diverse transient physical and electrical processes for each of their many components. This is an example of a coupled-domain simulation, i.e., the simultaneous simulation of different functional units [...]

Numerical Simulation of Pulse-Width-Modulated Micropumps with Diffuser/Nozzle Elements

Nguyen N-T., Huang X., Nanyang Technological University, SG

This paper presents the numerical simulation of a new control method for dynamic micropumps with diffuser/nozzle elements: the pulse-width-modulation (PWM) of the drive signal. A piezo disk with a square wave signal actuates the pump, [...]

Data on the Slip Coefficients

Sharipov F., Universidade Federal do Parana, BR

For mathematical modeling of micro fluidics it is necessary to calculate a rarefied gas ow through micropumps, microvalves and other elements with a high accuracy. Since the size of micro fluidics is close to the [...]

Theoretical Approximations for the Average Linear Flow of Carrier Gas Through a Rectangular GC Column

Spangler G.E., Technispan LLC, US

The ability of a gas chromatographic (GC) column to separate two compounds is determined by its analytical resolution. The height equivalent to a theoretical plate (HETP) is given by Eq. 1. For a rectangular column, [...]

Modeling of FlowFET Characteristics

Leung Ki Y.-S., Schasfoort R.B.M., Sclautmann S., Renaud Ph., van den Berg A., EPFL, CH

Classical electrokinetic theory demonstrates that modu-lation of the z-potential at the shear plane can alter both the magnitude and direction of Electroosmotic Flow (EOF) induced in a microchannel at low driving field strengths. In the [...]

Analysis of Sample Injection and Band-Broadening in Capillary Electrophoresis Microchips

Krishnamoorthy S., Giridharan M.G., CFD Research Corporation, US

An implicit finite-volume numerical scheme has been developed to solve the three-dimensional transport equations that govern the electroosmotic and electrophoretic phenomena. The scheme consists of solving the ion transport equation and electro-neutrality condition coupled with [...]

Stability Criterion for Microscale Concentric Flow of Two Immiscible Liquids

Ho L.W., Marchetti J., Gallegos C., IntelliSense Corporation, US

This paper addresses the establishment of a stability criterion for isothermal laminar concentric flow of two immiscible liquids. Using the approach of combined non-dimensional group anlysis and numerical simulations, it is established that the inner [...]

A Passive Fluid Valve Element for a High-Density Chemical Synthesis Machine

Moroney R.M., Amantea R., McBride S.E., Sarnoff Corporation, US

We have developed a passive valve element for use in a high-density chemical synthesis machine. The element stops fluid flow by the surface tension forces occurring at small channel openings. The openings are circular holes [...]

Unsteady Gaseous Flows in Tapered Microchannels

Aubert C., Colin S., Caen R., Laboratoire de Genie Mecanique de Toulouse, FR

The aim of the paper is to contribute to the modeling of unsteady slip flows in rectangular microchannels with slowly varying cross-sections. A model is proposed for a microdiffuser submitted to sinusoidal pressure fluctuations at [...]