a b s t r a c tHeat transfer enhancement in a channel with extended surfaces mounted at the top of the bottom plate is investigated by using the lattice Boltzmann method (LBM). Cold air is forced to flow in the channel while the bottom of the channel is heated and kept at a constant temperature. The effect of the Reynolds number (Re) and extended surfaces' height and spacing on the fluid flow and heat transfer are addressed in this work. It is found that the rate of heat transfer from the plate can be enhanced for certain arrangements.