Effect of actuation frequency on the performance of diffuser micropumps

Amin Mehrabian, M. T. Ahmadian

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

Valveless piezoelectric micropumps are in wide practical use due to their ability to conduct particles with absence of interior moving mechanical parts. The objective of this paper is to obtain the fluid flow response to actuation frequency of a passive diffuser valve under harmonic pressures. In this regards a 2D model of a micropump valves and chambers is analyzed. The analysis is performed for 10Kpa back pressure on micropump chamber and actuation frequencies within the range of 1 Hz to 10 KHz. Results show the highest velocity in the direction of diffuser axis occurs at the narrow diffuser neck while flow direction reverses every half period. For low frequencies, a parabolic velocity profile is observed at the valve midway while, instabilities with the tendency of transition to boundary layer dominant profile is observed for high actuation frequencies. Oscillating flow in diffuser indicates existence of high shear stress regions near the wall along with the flow reversal in the center at high frequencies. Both valve and pump net flow rate decrease drastically as the frequency approaches a certain value. From electrical analogy viewpoint, nozzle/diffuser passive valves can be modeled as Low Pass Filters (LPF). The results are in good agreement with the relevant analytical findings. Similar to analytical results, flow rate is approximately in phase with actuation at low frequencies but phase shift ascends as actuation frequency is increased. The main head loss of flow occurs at the diffuser valves while sudden contraction and expansion of streamlines at the diffuser entrance and exit involve only 22% of the total energy.

Original languageEnglish (US)
Title of host publicationProceedings of the 4th International Conference on Nanochannels, Microchannels and Minichannels, ICNMM2006
Pages725-731
Number of pages7
StatePublished - 2006
Event4th International Conference on Nanochannels, Microchannels and Minichannels, ICNMM2006 - Limerick, Ireland
Duration: Jun 19 2006Jun 21 2006

Publication series

NameProceedings of the 4th International Conference on Nanochannels, Microchannels and Minichannels, ICNMM2006
Volume2006 B

Other

Other4th International Conference on Nanochannels, Microchannels and Minichannels, ICNMM2006
Country/TerritoryIreland
CityLimerick
Period6/19/066/21/06

All Science Journal Classification (ASJC) codes

  • Engineering(all)

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