Working principle and performance of the dynamic micropump

Gerlach, Torsten; Wurmus, Helmut

doi:10.1016/0924-4247(96)80097-5

Cited by 169 publications

(62 citation statements)

References 6 publications

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“…This diffuser element is also employed in a PMMA valveless micropump with electromagnetic actuation (Yamahata et al 2005). Similar principle is used to fabricate the dynamic passive valve of another valveless pump (Gerlach and Wurmus 1995). This diffuser-valve is produced by anisotropic etching on a <100> silicon wafer.…”

Section: Valveless Micropumpmentioning

confidence: 99%

Unsteady flow behaviors in an obstacle-type valveless micropump by micro-PIV

Sheen

Hsu

et al. 2007

Microfluid Nanofluid

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In this paper, a PZT micropump excited by amplified squarewave signals with various frequencies was used to study the transient flow behaviors in an obstacletype valveless micropump. A micro-particle-image-velocimetry (micro-PIV) with an external trigger was developed to obtain flow fields at the outlet and around the obstacle with various phases in a cycle. In comparison with previous studies on the pump performance, such as pump pressure and volume flow rate, more detailed information about the pump was obtained. The velocity profiles and periodic sectional mean velocities exhibited the unsteady flow nature. The total net flow generation efficiency per cycle was obtained experimentally by integrating the phase-dependent velocities. The flow recirculation around the obstacle was observed and quantified to investigate the influence on the pump performance. The duration, circulation, and the size of the recirculation regions indicated that this flow behavior could enhance the flow-directing capability. These results are very useful for the design and improvement of obstacle-type valveless micropumps. Keywords Valveless micropump Á Externally triggered micro-PIV Á Micro oscillating flow Á Flow recirculation List of symbols A o Area of grid cell (mm 2 ) d Diameter of a glass tube d p Diameter of seeding particle (lm) D f Diffusion coefficient (m 2 /s) h Height of liquid in a glass tube I Fluid inductance (Pa s 2 /m 3 ) n Radial oscillating frequency n o Refraction ratio NA Numerical aperturê Q Volume of flow rate (m 3 /s) r Characteristic length of channel (lm) R Flow resistance (Pa s/m 3 ) t Specific time in a time period (s) t r Response time of tracer particle (s) T Time of a period (s) u i Velocity in x or y direction (mm/s) U o Maximum velocity at each velocity profile (mm/s) Wo Womersley number Y o Channel width (lm) Z Complex form of flow impedance (Pa s/m 3 )Greek alphabets dz o Depth of correlation (lm) DP Complex form of pressure drop (Pa) DtTime interval between the laser pulses (s) e i Errors due to Brownian motion G Circulation (mm 2 /s) gThe flow-directing efficiency of a valveless flow rectifier g o Flow rate ratio of pump/supply

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Section: Valveless Micropumpmentioning

confidence: 99%

Unsteady flow behaviors in an obstacle-type valveless micropump by micro-PIV

Sheen

Hsu

et al. 2007

Microfluid Nanofluid

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“…Several investigations related to the flow characteristics of valve-free micro-pumps have been theoretically and empirically reported. Gerlach and Wurmus [8] developed a static model to describe the valve-free micro-pump. Olsson et al [9] also reported new operational principles for a micropump with two chambers in parallel, Olsson et al [10] further mentioned that a spring-mass system can be used to monitor the motion of the diaphragm in the micro-pump for the energy balance between the kinetic energy for incompressible fluid flowing through a diffuser and the potential energy of the diaphragm as it vibrates.…”

Section: (1)mentioning

confidence: 99%

Performance of Nozzle/Diffuser Micro‐Pumps Subject to Parallel and Series Combinations

2006

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This study numerically examines the performance of micro nozzle/diffuser pumps subject to parallel and series combinations. For a single-chamber micro nozzle/diffuser micro-pump, four stages are identified. For dual micro-pumps in a parallel combination, the flow field in each chamber is symmetrical about the center line of the arrangement. For in-phase operation, the maximum flowrate is about two times higher than that of the single-chamber. For micro-pumps in a series combination, it is found that the overall performance is strongly related to the phase angle. The effective flowrate can be significantly increased, decreased, or even reversed. This indicates that the flowrate can be controlled within a wide span by changing the phase angles. At a phase angle of 90°, an eight-fold increase of effective flowrate is seen relative to that of a single-chamber operation. The significant increase of flowrate is attributed to two effects; the first effect is due to the "active valve" effect that increases the efficiency during pump mode. The second influence is attributed to the increased pressure difference that brings in more fluid during supply mode.

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“…An alternative approach is to use mathematical models. A number of studies (Stemme and Stemme 1993;Gerlach and Wurmus 1995;Olsson et al 1999;Pan et al 2003;Ullmann 1998) have applied this approach, largely employing a onedimensional description. The complexity of many such models means that it is difficult to draw any general conclusions.…”

Section: Introductionmentioning

confidence: 99%

Analysis of double-chamber parallel valveless micropumps

Azarbadegan¹,

Cortes-Quiroz²,

Eames³

et al. 2009

Microfluid Nanofluid

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The characteristics of a double-chamber valveless parallel micropump are analysed using a one-dimensional non-linear model. The relationships between the mean volume flux, pressure difference and (measurable) characteristics of the pump are derived in a closed-form expression which are validated against the numerical solutions. These results show that when pump chambers are driven exactly out of phase, the volume flux is maximum and the variation of the pump chamber pressure is (significantly) reduced. The model predictions were tested against the experimental results of Olsson et al. (Sens Actuators A Phys 47:549-556, 1995) for both in and out of phase pumps. The mean volume flux decreases linearly with pressure rise. For both cases, the agreement is good and is an improvement over previous analytical models. The implications of these results for optimal pump design are discussed

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Working principle and performance of the dynamic micropump

Cited by 169 publications

References 6 publications

Unsteady flow behaviors in an obstacle-type valveless micropump by micro-PIV

Unsteady flow behaviors in an obstacle-type valveless micropump by micro-PIV

Performance of Nozzle/Diffuser Micro‐Pumps Subject to Parallel and Series Combinations

Analysis of double-chamber parallel valveless micropumps

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