Effect of Al2O3 nanoparticle deposition on flow boiling performance of water in a microchannel

Flow boiling performance of a Cu microchannel coated with Al2O3 nanoparticle has been investigated experimentally. Experiments were performed in a single microchannel having hydraulic diameter of 672 μm using de-ionized (DI) water as the coolant. Surface morphology of the microchannel was modified by depositing nanoparticles through pool boiling of ethanol based alumina (Al2O3) nanofluid. Flow boiling, along with single-phase convective heat transfer experiments were performed at different mass flux and different inlet sub-cooling. Results from the microchannel with bare surface are used as the reference data. Nanoparticles deposited surface was found effective in enhancing the critical heat flux (CHF); up to 39% enhancement in CHF was observed in this experimental range. However, the heat transfer coefficient (HTC) was observed to be reduced marginally for the nanoparticles coated surface compared with the bare surface.

► Nanoparticles coated surface increases surface wettability.
► CHF increases for the nanoparticles coated surface by ∼39%.
► HTC decreases for the nanoparticles coated surface.