NUMERICAL MODELLING OF THERMOCAPILLARY FLOW ON SUPERHYDROPHOBIC SURFACES

A liquid in Cassie-Baxter state confined between two microstructured superhydrophobic surfaces has a large free surface fraction while at the same time being in close contact to a solid. As such this configuration is predestined for thermocapillary transport when applying a temperature gradient along the structured substrate. We numerically investigate thermocapillary flow over superhydrophobic arrays of fins. Since even moderate temperature gradients of the order of a few K/cm can induce flow velocities of several mm/s, this setup lends itself for microfluidic pumping. We compare the numerical results to an analytical expression for the flow velocity obtained in the limit of Stokes flow.