We present a hybrid molecular-continuum method for the simulation of general nano-fluidic networks, which consist of a multiscale system of channels with high aspect ratios. This develops on the hybrid molecular-continuum internal multiscale method recently devised by Borg et al. [1, 2] with three main additions: a) method generalisation to accurately model any nano-fluidic network, rather than just serial channel systems; b) density correction, enabling the modelling of compressible fluids; and c) utilisation as a design tool, rather than just a simulation tool, by replacing pressure boundary conditions for the network with mass flow rate boundary conditions (inlet/outlet pressures are the output of the simulation).
We compare our multiscale method with a full molecular dynamics (MD) simulation for a bifurcating channel network, and show that it converges quickly, within 3 iterations, and with good agreement. The multiscale method produces errors of < 2%, while providing a computational speed up of 2.1. The speed up demonstrated is far more modest than it would be for larger networks, but our validation case is restricted by the need to perform a full MD simulation.