Enhanced flow boiling in a microchannel with integration of nanowires

Convective heat transfer performance of a micro-channel with copper nanowires (CuNWs) coatings has been investigated experimentally. Experimental studies were carried out on a bottom surface heated single micro-channel of 672 μm hydraulic diameter using de-ionized (DI) water as coolant. Nanowires were directly grown on the bottom surface of the micro-channel using electrochemical deposition technique. Both single-phase and two-phase convective heat transfer experiments were performed at different mass flux and different degree of sub-cooling. The results from microchannel with bare surface are used as the baseline data. CuNWs coatings have been found to enhance single-phase heat transfer rate by up to ∼25%, whereas in the flow boiling regime, the enhancement was up to ∼56% with a pressure drop increase by ∼20% in the single-phase regime. The obvious change of pressure drop in the fully developed boiling regime was not observed. ► CuNWs coating reduces surface superheat temperature for the onset of nucleate boiling by 4–12 °C depending on the flow rate. ► CuNWs coating does not show any significant effects in managing the two-phase flow instability. ► CuNWs coating enhances flow boiling heat transfer rate up to ∼56%. ► CuNWs coated surfaces are more effective at lower degree of sub-cooling.