Heat Transfer during Flow Boiling of Water in Short Microchannel with High Aspect Ratio

The paper presents results of experimental research on the influence of the mass flux on the heat transfer during flow boiling of subcooled de-ionized water in conditions of three-side heating in a system of two microchannels with an aspect ratio of 13.3. The horizontal experimental section was a copper block with two microchannels 2 mm wide, 0.15 mm deep, and 16 mm long; the inner surface of the microchannels was covered with a thin layer of nickel with hydrophilic nanoparticles of Aerosil 200. The mass flux varied from 500 to 3500 kg/m extsuperscript2s; the initial water subcooling relative to the saturation temperature at the microchannel outlet was 80°C. The dependence of the superheat of the wall on the heat flux density was determined; the critical heat fluxes were measured; comparison of the obtained data with calculation based on the binomial equation for subcooled boiling in a microchannel was carried out.