Enhanced nucleate boiling in microchannels

This paper studies the nucleate boiling conditions and mechanisms in plasma etched silicon microchannels below 150 mum hydraulic diameter. Boiling regimes and the wall superheat in microchannels with various DI water surface tensions and wall surface roughness are discussed. The experiments show that wall superheat in microchannels is primarily due to the lack of active nucleation sites rather than limited channel space or a high liquid surface tension. By creating small cavities in the channel walls, superheat can be eliminated from as small as 28 mum hydraulic diameter silicon channels.