Structural parameter analysis and experimental study of micropumps with saw-tooth microchannel

• The influence to the micropump of the novel saw-tooth microchannel structural parameters hasn’t been discussed.
• The structural and fabrication technology of the micropump are different from other micropumps.
• Five saw-tooth micropumps with different structural parameters have been fabricated, through experiment the results showed that the micropump performance with optimal structural parameters is the best.

The changing trends of vortex, pressure loss, microchannel efficiency and instantaneous flow rate along with Reynolds number are discussed based on the structural parameters of a saw-tooth microchannel that include diffuser angle, sectional width, length, taper angle and depth. Through finite element analysis it is shown that the nozzle flow is steadier than diffuser angle. The optimal range of diffuser angle is 5–9°. The channel efficiency decreases with an increase of sectional width, and the optimal value is 0.04 mm according to the technology conditions. The pressure loss increases with increasing length. The channel performance is best when the taper angle is in the range 20–40°. The channel efficiency increases with an increase of depth, but, with this increasing depth, the wall friction force increases, and the fabrication processing becomes more difficult. Finally, five micropump structures were designed and fabricated with deep reactive ion etching technology based on silicon wafers. The five micropumps were irreversibly sealed with polydimethylsiloxane (PDMS) on both sides using ultraviolet irradiation of the PDMS. For testing the flow rate and pressure of the five micropumps, a test-bed was established. The results show that the flow rate and pressure of one of the micropumps are maximal values under sine, square and triangular driving waves. This agrees well with the results of the structural parameter analysis. When the driving frequency is 200 Hz, the maximum flow and pressure are 63.6 μl/min and 1.3 kPa respectively.