Cross-sectional shape effect of a diffuser micropump on flow rates

Presented is the effect of cross-sectional shapes in a diffuser micropump using a hetero-shaped fluidic channel. The hetero-shaped fluidic channel consists of two regions with different cross-sectional shapes: a semi-cylindrical shape for the inlet and a rectangular shape for the outlet. The semi-cylindrical-shaped channel can produce almost zero dead volume in a closed state; thus, the flow rate of the micropump should be enhanced. To evaluate the effect of the cross-sectional shape, both hetero-shaped and homo-shaped micropumps were fabricated with the same cross-sectional area. The flow rate of both micropumps was evaluated in terms of frequency and duty ratio. The experimental comparison demonstrated that the hetero-shaped micropump is generally superior to the homo-shaped one with regards to flow rate. The ratio of the maximum flow rate between the two types was more than five for the experiments performed in this study. The acquired maximum flow rate of the hetero-shaped micropump was 38.76 nl min, which is ten times larger than that of the homo-shaped micropump in identical conditions (frequency: 3 Hz; duty ratio: 50 ). Moreover, the hetero-shaped micropump performed the valve function without additional devices.