Convective heat transfer to shear-driven liquid film flow in a microchannel

Experimental study on heat transfer to a liquid water film in a microchannel was performed. The liquid film was introduced into a nitrogen stream through a 350 μm circular hole upstream of a 1 mm × 1 mm heater in a 220 μm deep and 1.5 mm wide rectangular microchannel. Average heat transfer coefficient was obtained for different gas and liquid flow rates and results were compared to single-phase flow. Significant improvement in heat transfer performance was observed with no appreciable change in pressure drop. Experimental data combined with a heat transfer analysis was used to infer the mechanisms controlling the heat transfer process.