Fabrication and characterization of truly 3-D diffuser/nozzle microstructures in silicon

Heschel, M.; Müllenborn, M.; Bouwstra, S.

doi:10.1109/84.557529

Cited by 45 publications

(31 citation statements)

References 5 publications

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“…The rectification efficiency of nozzle-diffuser micropumps reported in the literature is very low, generally between 0.01 and 0.2. Since the rectification efficiency of these micropumps depends on the flow directing ability of the nozzle-diffuser elements, many studies have been directed at better understanding the fluid dynamic behavior and the flow rectification properties of nozzle-diffuser elements [11,14,[17][18][19][20]23,24]. Different shapes of nozzle-diffuser elements have been considered in the literature.…”

Section: Nozzle-diffuser Elementsmentioning

confidence: 99%

Low Reynolds number flow through nozzle-diffuser elements in valveless micropumps

Singhal

Garimella

Murthy

2004

Sensors and Actuators A: Physical

124

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Section: Nozzle-diffuser Elementsmentioning

confidence: 99%

Low Reynolds number flow through nozzle-diffuser elements in valveless micropumps

Singhal

Garimella

Murthy

2004

Sensors and Actuators A: Physical

124

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“…10 This planar diffuser/ nozzle structure was also implemented in micropumps. 11,12 Another interesting planar structure with rectification property is the Tesla valve. 13 The Tesla valve is a microfluidic network with a side loop joining the main channel at a sharp angle.…”

Section: Introductionmentioning

confidence: 99%

Improvement of rectification effects in diffuser/nozzle structures with viscoelastic fluids

Nguyen

Lam

et al. 2008

Biomicrofluidics

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This paper reports the improvement of rectification effects in diffuser/nozzle structures with viscoelastic fluids. Since rectification in a diffuser/nozzle structure with Newtonian fluids is caused by inertial effects, micropumps based on this concept require a relatively high Reynolds numbers and high pumping frequencies. In applications with relatively low Reynolds numbers, anisotropic behavior can be achieved with viscoelastic effects. In our investigations, a solution of dilute polyethylene oxide was used as the viscoelastic fluid. A microfluidic device was fabricated in silicon using deep reactive ion etching. The microfluidic device consists of access ports for pressure measurement, and a series of ten diffuser/nozzle structures. Measurements were carried out for diffuser/nozzle structures with opening angles ranging from 15°to 60°. Flow visualization, pressure drop and diodicity of de-ionized water and the viscoelastic fluid were compared and discussed. The improvement of diodicity promises a simple pumping concept at low Reynolds numbers for lab-on-a-chip applications.

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“…The flow rates vary from 6,010 ll/min for the nozzle/diffuser micropump of Heng et al (1999) to 0.002 pl/min of Bao and Harrison (2003). Both AC and DC sources have been used (Bendib and Français 1999;Heng et al 2000;Heschel et al 1997;Huang et al 1999Huang et al , 2000. With regard to micromachining processes, bulk micromachining of silicon using LIGA, inductively coupled plasma reactive ion etching (ICP-RIE), and anisotropic wet etching together with soft lithography have been used.…”

Section: Introductionmentioning

confidence: 99%

High-current density DC magenetohydrodynamics micropump with bubble isolation and release system

Nguyen

Kassegne

2008

Microfluid Nanofluid

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One of the major challenges for integrated Labon-a-Chip (LOC) systems is the precise control of fluid flow in a micro-flow cell. Magnetohydrodynamics (MHD) micropumps which contain no moving parts and capable of generating a continuous flow in any ionic fluid offer an ideal solution for biological applications. MHD micropumping has been demonstrated by using both AC and direct current (DC) currents by a number of researchers with varying degrees of success. However, current MHD designs based on DC do not meet the flow rate requirements for fully automated LOC applications ([100 ll/ min). In this research, we introduce a novel DC-based MHD micropump which effectively increases flow rate by limiting the effects of electrolysis generated bubbles at the electrode-electrolyte interface through isolation and a mechanism for their release. Gas bubbles, particularly, hydrogen generated by high current density at the electrodes are the main culprit in low experimental flow rate compared with theoretical values. These tiny bubbles coalesce in the flow channel thus obstructing the flow of fluid. Since hydrolysis is inevitable with DC excitation, compartmentalized electrode channels with bubble isolating and coalescence retarding mechanisms and bubble release systems are implemented to prevent the coalescence of these bubbles and minimize their effects on flow rate. In this novel design called bubble isolation and release system, flow rate of up to 325 ll/min is achieved using 1 M NaCl solution in DC mode with potentials of 5 V and current density of about 5,000 A/m 2 for a main channel of 800 lm 9 800 lm cross-section and 6.4 mm length.

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Fabrication and characterization of truly 3-D diffuser/nozzle microstructures in silicon

Cited by 45 publications

References 5 publications

Low Reynolds number flow through nozzle-diffuser elements in valveless micropumps

Low Reynolds number flow through nozzle-diffuser elements in valveless micropumps

Improvement of rectification effects in diffuser/nozzle structures with viscoelastic fluids

High-current density DC magenetohydrodynamics micropump with bubble isolation and release system

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