Forced Convective and Subcooled Flow Boiling Heat Transfer to Water–Al2O3 Microfluid in an Annular Heat Exchanger

An experimental study has been conducted on subcooled nucleate flow boiling heat transfer of water–Al2O3 particulate liquid inside a vertical annulus. The experimental apparatus provides the particular conditions to investigate the influence of heat flux, flow rate, inlet temperature, and particle concentration on the heat transfer coefficient in both single-phase convection and two-phase nucleate boiling regimes. Operating conditions are subcooling temperature (30–50 °C), volume flow rate (2–4 l/min), heat flux (8–110 kW/m2), and particle concentration (0.01–0.03 vol%). The experimental data is in good agreement with well-known Chen model with the accuracy of 10.84%.