A numerical investigation is carried out that show how reasonably good thermal performances can be obtained with cross-flow microchannel heat sinks provided that an unequal number of microchannels is used in the two layers and a non-uniform microchannel inlet velocity distribution is produced by properly designed headers. All the numerical simulations are carried out using an in-house FEM procedure which solves the parabolized form of the Navier-Stokes equations in a computational domain corresponding to a single microchannel. Then the velocity field thus obtained is appropriately scaled and mapped onto the fluid parts of the 3-D domain corresponding to the whole microchannel heat sink, where the elliptic form of the energy equation is solved.
