A Comparative Study of Nozzle/Diffuser Micropumps with Novel Valves

Abstract

This study conducts an experimental study concerning the improvement of nozzle/diffuser micropump design using some novel no-moving-part valves. A total of three micropumps, including two enhancement structures having two-fin or obstacle structure and one conventional micro nozzle/diffuser design, are made and tested in this study. It is found that dramatic increase of the pressure drops across the designed micro nozzles/diffusers are seen when the obstacle or fin structure is added. The resultant maximum flow rates are 47.07 mm3/s and 53.39 mm3/s, respectively, for the conventional micro nozzle/diffuser and the added two-fin structure in micro nozzle/diffuser operated at a frequency of 400 Hz. Yet the mass flow rate for two-fin design surpasses that of conventional one when the frequency is below 425 Hz but the trend is reversed with a further increase of frequency. This is because the maximum efficiency ratio improvement for added two-fin is appreciably higher than the other design at a lower operating frequency. In the meantime, despite the efficiency ratio of the obstacle structure also reveals a similar trend as that of two-fin design, its significant pressure drop (flow resistance) had offset its superiority at low operating frequency, thereby leading to a lesser flow rate throughout the test range.

Analytical modeling, simulations and experimental studies of a PZT actuated planar valveless PDMS micropump

“…Ullmann et al [13] studied performance of valveless micropumps of different configurations including parallel and series connection of multiple micropumps. Yang et al [14] presented an improved design of valveless micropump without any moving parts. Guo et al [15] reported a parallel double chamber as a modification to the basic valveless micropump design.…”

“…From the literature review, it is clear that experimental investigations of PZT actuated valveless micropumps including microfabrication and experiments have been reported by various research groups in the past few years [11][12][13][14][15][16][17][18][19][20][21]. Also, many approximate analytical and simulation models have been reported [22][23][24][25][26][27][28][29][30][31][32][33].…”

Microfluidic Pumping Utilizing a PDMS Membrane With an Integrated Nonuniform Open-Porous Foam

“…Owing to the difference in hydrodynamic resistance of the nozzle and the diffuser a unidirectional net flow is induced in the microfluidic system. Since no moving parts are encountered with these elements, wear and fatigue are eliminated with the drawback of low efficiency compared to check-valves or other active valves [4]. A typical realization of such a valve-less micropump in glass technology is given in [5].…”

“…Microfluidic pumps are key parts for the development of highly integrated LOC and μTAS systems. Peristaltic membrane pumps utilizing nozzle-diffuser structures, which number among the mechanical displacement pumps [3], are typically designed in such a way that the movable membrane induces pressure strokes on a fluid volume and the geometrical shape of inlet and outlet resembles a nozzle and a diffuser structure [4], respectively. Here geometrical constrictions and widenings of the fluid channel are used as flow directing elements.…”

Fabrication of Magnetically Driven Microvalve Arrays Using a Photosensitive Composite

“…Therefore, µTAS are expected to be applied in point-of-care testing, where a chemical or biochemical test is performed and results are obtained immediately. Several microfluidic devices have been developed for the µTAS, such as micropumps [1,2], micromixers [3,4], and microvalves [5,6]. In particular, microvalves play an important role in fluid control and sample sorting in the µTAS.…”