Comparative evaluation of microfluidic circuit model performance for electroviscous flow

Abstract

Microfluidic circuit models are useful tools for conceptualising and designing lab-on-chip devices. We evaluate the ability of two different microfluidic circuit models to accurately predict electroviscous (pressure driven) flow behaviour in a particular contraction-expansion geometry over an experimentally relevant range of inlet concentrations and surface charge densities. We show that a linear `total current model' based on a relatively simple ion species constraint at circuit nodes performs well compared to a non-linear `ion current model' that conserves species exactly. Specifically, the total current model over-predicts the total pressure and potential differences by less than 2% and 7% respectively for silica channels. References

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