Abstract
Subcooled flow boiling of water in a horizontal rectangular channel was investigated by experiment for two kinds of rough heating surfaces polished with emery papers and a grooving surface. Microbubble Emission Boiling, MEB, occurred in transition boiling at high liquid subcooling and high liquid velocity. For the grooving surface, MEB is more difficult to occur than other surfaces even at high liquid subcooling, and the heat flux increase was smaller in MEB. The experimental result shows that the wettability is poor for the grooving surface. The periodic type of MEB occurred for the experimented heating surfaces and the heat fluxes increased with the increasing of frequency of pressure fluctuation in the channel.
