Simulation of a microfluidic flow-focusing device.

We present a model of microfluidic flow of several completely immiscible fluids and use it to simulate a whole flow focusing device chamber. Our efficient, practical model supports a large parameter space, spanned by surface wetting, surface tension, liquid-liquid wetting, viscosity ratio, and inlet velocity. It is based upon an N-component lattice Boltzmann method with interrupted coalescence [Dupin, Philos. Trans. R. Soc. London, Ser. A 362, 1885 (2004)], here adapted for calculations at low capillary and Reynolds numbers, with wetting and significantly reduced spurious flow. Results over 2 orders of magnitude in Reynolds number are presented.