Theoretical analysis of the low-voltage cascade electro-osmotic pump

The recently published experimental results obtained by Takamura et al. [Y. Takamura, H. Onoda, H. Inokuchi, S. Adachi, A. Oki, Y. Horiike, in: J.M. Ramsey, A. van den Berg (Eds.), Proceedings of the μTAS 2001, Monterey, CA, USA, Kluwer Academic Publishers, Drodrecht, 2001, p. 230], on their low-voltage cascade electro-osmotic pump are analyzed using two different theoretical approaches. One is the semi-analytical equivalent circuit theory involving hydraulic resistances, pressures, and flow rates. The other is a full numerical simulation using computational fluid dynamics. These two approaches give the same results, and they are in good qualitative agreement with the published data. However, our theoretical results deviate quantitatively from the experiments. The reason for this discrepancy is discussed.