Simulation and optimization of a microfluidic flow sensor

Rasmussen, A.; Mavriplis, Catherine; Zaghloul, Mona; Mikulchenko, Oleg; Mayaram, K.

doi:10.1016/s0924-4247(00)00503-3

Cited by 55 publications

(21 citation statements)

References 32 publications

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“…Other flow-measuring devices comprised piezoelectric elements, resonating microbridges, thermistors, Prandtl tubes, etc. [146]. Recently, a noninvasive optical flow sensing principle and its application was demonstrated by [147].…”

Section: Flow Measurementmentioning

confidence: 99%

New advances in microchip fabrication for electrochromatography

Szekeres

Guttman

2005

Electrophoresis

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There is a great demand in separation technologies for faster and more effective analysis processes. Miniaturization is a suitable technique for satisfying this demand as reduction in size gives increased separation speed with higher efficiency. CEC is an electric-field-mediated separation technique where the liquid flow is generated by the electric field itself. The main advantage of using electric field over pressure for flow generation is the flat flow profile of the EOF; thus, CEC is one of the best candidates to construct a novel and high-efficiency microanalytical device. The aim of the present paper is to review the basic fabrication and bonding principles, as well as connection and system integration options for microfluidics-based electrochromatography. The physical structure and fluidic channel formation are critically evaluated, including glass microstructuring and fusion bonding. Recent developments in nanoflow measurements and the application of various flow control units are also extensively discussed.

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Section: Flow Measurementmentioning

confidence: 99%

New advances in microchip fabrication for electrochromatography

Szekeres

Guttman

2005

Electrophoresis

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“…Because of good sensitivity at low flow rates, which are generally typical of the flows in microchannel reactors [6], we chose the calorimetric flow sensor type as the target of our study.…”

Section: Introductionmentioning

confidence: 99%

A micromachined thin-film gas flow sensor for microchemical reactors

Shin¹,

Besser

2006

J. Micromech. Microeng.

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As microchemical systems (MCS) have gained in importance since their introduction in the last decade, it has become recognized that appropriate sensing and control capabilities are needed if MCS are to reach their potential. In this context, we present a study of the working behavior of a novel thin-film micro flow sensor which is integrated with a silicon microreactor with a submillimeter channel. A simple-to-fabricate device based on the concept of calorimetric sensing was chosen as a model structure to understand the important factors controlling sensor performance. Various design options for the sensor were explored by the use of computational fluid dynamics simulations. We found that sensitivity depends strongly on certain design factors. In summary, sensitivity is improved with (a) higher values of the resistors that detect flowinduced temperature changes, (b) shorter distances between the resistor that provides a source of heat and the thermally sensitive resistors and (c) higher input power to the heating resistor. Item (a) was found to have by far the strongest effect of the three. Reproducibility tests were conducted and the sensor exhibited consistent performance throughout the entire test range of 0 to 20 sccm which is an appropriate fit to the flow capacity of the microchannel. Finally, response time was assessed by simulating the transient behavior of the sensor with a thermal capacitance model, which yielded an accurate prediction of the experimental response of the device. The response time is approximately 70 msec at a typical flow rate of 10 sccm.According to the understanding gained by the model, the sensor response time can be improved by reducing the substrate thickness, using a lower density substrate material, and increasing the convective heat transfer coefficient in the channel.3

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“…Other sensor types were also based on pressure drop measurement over a well-characterized hydraulic resistance [107]. Flow measuring concepts comprising piezoelectric elements, resonating microbridges, thermistors, Prandtl tubes, etc., have also been evaluated [108].…”

Section: Methods To Measure Eofmentioning

confidence: 99%

Theoretical and nomenclatural considerations of capillary electrochromatography with monolithic stationary phases

Végvári

Guttman

2006

Electrophoresis

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During the past decade, CEC has been one of the few novel achievements in the field of separation science attracting a wide interest. The technology progress permitted the realization of the long-sought idea to employ an electroosmotically driven flow through the columns improving the separations in terms of both resolution and efficiency. The early practical obstacles related to the use of conventional bead-packed columns have been solved by the introduction of continuous beds, also known as monoliths. Hitherto, various synthesis approaches have been successfully developed producing monolithic beds in situ in capillary columns, sharing similar physical structure built up of tiny particles (in the sub-microm range) that are covalently linked together and to the capillary wall. Parallel with the practical column technology studies, the theory of electrochromatography has been continuously developed, focusing on such basic issues as EOF characterization, separation efficiency, and peak dispersion effects. This review provides a short introduction to the theory of CEC with special attention to monolithic separation beds. The paper also summarizes the latest achievements in CEC and discusses the nomenclature, EOF characteristics, and some specific advantages of monolithic column technology.

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Simulation and optimization of a microfluidic flow sensor

Cited by 55 publications

References 32 publications

New advances in microchip fabrication for electrochromatography

New advances in microchip fabrication for electrochromatography

A micromachined thin-film gas flow sensor for microchemical reactors

Theoretical and nomenclatural considerations of capillary electrochromatography with monolithic stationary phases

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