Low Reynolds number fluidic flowmetering

Boucher, R.F.; Mazharoǧlu, Çetin

doi:10.1088/0022-3735/21/10/015

Cited by 19 publications

(4 citation statements)

References 2 publications

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“…The instabilities are typically found at Reynolds numbers of the order from Re ∼10 1 to 10 2 . The versions with feedback loop operate typically at higher Re ∼10 3 or more, though with some care (usually calling for empirical development to suppressing sensitivity to various side effects, [26]) they may be developed to operate also at lower values Re ∼10 1 or 10 2 . At Re values below this limit, oscillation may be irregular and even disappear as the available energy is consumed by viscous damping.…”

Section: Introductionmentioning

confidence: 99%

Oscillator micromixer

Tesař

2009

Chemical Engineering Journal

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a b s t r a c tA no-moving-part microfluidic oscillator was developed for mixing two reactants prior to their admission into a microreactor. Instead of the spatial periodicity produced by static mixers, it achieves essentially the same resultant effect by temporal periodicity. In one half of the oscillation period the oscillator directs into its output one reactant, followed by the other reactant during the other half-period. Since the periods are short, the flow in the output channel consists, like in the static mixers, of interleaved layers of the two fluids -here, however, oriented perpendicularly relative to the flow direction. The oscillation depends on dynamic effects so that there is a lower limit of Reynolds numbers at which the device can operate. In experiments this limit was at Re ∼30, which makes the device well suited for use with present-day microreactors, especially if the mixer is used to supply several reactors in parallel. Data from experiments with two different models agree with very simple kinematic theory for oscillation frequency and for the size of the generated layers in the output.

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Section: Introductionmentioning

confidence: 99%

Oscillator micromixer

Tesař

2009

Chemical Engineering Journal

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“…It is true that the flowmeter would operate without the knife edges; however, this then would simply be a vortex shedding flowmeter. The purpose of the knife edges is to speed up the oscillations within the metre and allow much lower Reynolds number flows to be measured (Boucher and Mazharoglu 1988). Such devices are typically of simple design with no moving parts.…”

Section: Vortex Shedding Flowmetermentioning

confidence: 99%

“…The original experimental work was conducted by Boucher and Mazharoglu (1988), Priestman and Boucher (2006). In this experiment an oil rig was built for Reynolds numbers lower than 800 and an air rig was used for Reynolds numbers from 800 to 9500.…”

Section: Model's Geometrymentioning

confidence: 99%

Fractal Orifices in Pipe

Nicolleau

2016

Fractal Flow Design: How to Design Bespoke Turbulence and Why

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The practical problem consists in measuring flow rates or flow speeds efficiently. Ideally, one would like to measure the flow rate accurately while affecting the flow as little as possible, generating very little extra pressure drop and flow disturbances while keeping to simple measuring devices. Sharp-edged orifice metres are the most common instruments used for flow rate measurement (about 50 % of the market). This is mainly because they are simple mechanical devices, easy to manufacture and without any moving part. However, they are rather energy inefficient. They consist in a circular hole drilled on a thin plate. The plate is then inserted into the pipe to create a pressure drop from which a mean flow-rate-based velocity can be deduced. An alternative, more efficient approach would be to redesign the circular orifice to control the flow. Here, we proposed to replace the 'classical circular orifice' by a fractal-based orifice. We found significant improvements with the fractal pattern. The main results are that the pressure loss which is the direct cost of the flowmeter is decreased by around 10 % with some fractal designs while the pressure drop across the orifice that is actually used for the measurement is barely affected.

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“…Recent advances in microfabrication technologies have been so promising that some micro-fluidics may compete with conventional mechanical and electrical systems. Fluidic devices such as feedback fluidic oscillators (Zemel and Furlan, 1996;Parry et al, 1991;Trippetts et al, 1973) and fluidic flowmeters (Lua and Zheng, 2003;Mansy and Williams, 1989;Boucher and Mazharoglu, 1988) consist of complex three-dimensional passages. Numerical studies on such fluidic devices are essential to reveal flow characteristics and to find their optimal geometrical parameters for designing.…”

Section: Introductionmentioning

confidence: 99%

A two‐dimensional numerical procedure for a three dimensional internal flow through a complex passage with a small depth (its application to numerical analysis of fluidic oscillators)

Nakayama

Kuwahara

Kamiya

2005

International Journal of Numerical Methods for Heat &Amp; Fluid Flow

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Purpose -To introduce an efficient two-dimensional numerical procedure for a three-dimensional internal flow through a complex passage with a small depth, in which the viscous effects from upper and lower walls are significant. Design/methodology/approach -A set of two-dimensional governing equations has been derived by integrating the full three-dimensional Navier-Stokes equations over the depth. Then, this set of the governing equations has been discretized using a finite volume method. Simple algorithm and quick scheme are used to solve the resulting discretized equations. Findings -A numerical experiment conducted to investigate the oscillation mechanism of a feedback fluidic oscillator reveals that the feedback passage plays an important role of transmitting the pressure rise to the control port, which triggers the jet stream to deflect towards the opposite side wall in the reaction region. Comparison of the prediction and experiment substantiates the validity of the present numerical procedure. Originality/value -The two-dimensional numerical procedure, proposed in this study, will be used by researchers and practitioners to investigate various kinds of complex passages with a small depth. Especially, those who are interested in fluidic devices may find it extremely convenient to conduct numerical experiments.

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Low Reynolds number fluidic flowmetering

Cited by 19 publications

References 2 publications

Oscillator micromixer

Oscillator micromixer

Fractal Orifices in Pipe

A two‐dimensional numerical procedure for a three dimensional internal flow through a complex passage with a small depth (its application to numerical analysis of fluidic oscillators)

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