Active Nucleation Site Density during Subcooled Flow Boiling at Vertical Narrow Rectangular Channel

At present work,visualized subcooled flow boiling experiments were conducted using a flat stainless steel surface heater.Results indicate that the active nucleation site density of narrow channel is with the same tendency as the regular channels,which is proportioned to the heat flux.Mass flux is with little ef-fect on the active nucleation site density of channel,but with effect on the onset of nucleate boiling.With the same heat flux,the narrower the channel,the highter the active nucleation site density.The effect of channel width on the active nucleation site density increases with the increasing of the heat flux.