TY - GEN
T1 - Evaporation induced cavitation in nanochannels
AU - Duan, Chuanhua
AU - Lu, Ming-Chang
AU - Karnik, Rohit
AU - Majumdar, Arun
PY - 2010/12/1
Y1 - 2010/12/1
N2 - Cavitation refers to a nucleation phenomenon that occurs at room temperature when the liquid pressure is below the corresponding saturation vapor pressure. Although water confined by a nanochannel and a liquid-air meniscus is under negative pressure, i.e. much smaller than the corresponding satraton vapor pressure, cavitation has not been observed in any nanochannels. In this work, we report our observation and studies of cavitations in nanochannels for the first time. 1-D confined nanochannels for this work were fabricated based on a sacrificial-layer-etching scheme. The unique cavitation phenomenon occurred when water started evaporation at the nanochannel entrances. Instead of meniscus recession, a bubble was present inside the nanochannel and two meniscii were pinned at the entrances. This bubble started growing along both directions until it totally occupied the whole channel. We found that the bubble grows linearly with time and the bubble growth rate decreases with the increasing channel height. A theoretical model was developed to study this dynamic process. It is found that the bubble growth rate is determined by the evaporation rate at the entrance. Since the total evaporation flux is a constant, the predicted bubble growth rate is reversely proportional to the channel height, quantitatively consistent with the experimental results. Since most current studies for caviation are theoretical studies, our studies provide a new experimental approach to study these phenomena in artificial transparent nanochannel devices.
AB - Cavitation refers to a nucleation phenomenon that occurs at room temperature when the liquid pressure is below the corresponding saturation vapor pressure. Although water confined by a nanochannel and a liquid-air meniscus is under negative pressure, i.e. much smaller than the corresponding satraton vapor pressure, cavitation has not been observed in any nanochannels. In this work, we report our observation and studies of cavitations in nanochannels for the first time. 1-D confined nanochannels for this work were fabricated based on a sacrificial-layer-etching scheme. The unique cavitation phenomenon occurred when water started evaporation at the nanochannel entrances. Instead of meniscus recession, a bubble was present inside the nanochannel and two meniscii were pinned at the entrances. This bubble started growing along both directions until it totally occupied the whole channel. We found that the bubble grows linearly with time and the bubble growth rate decreases with the increasing channel height. A theoretical model was developed to study this dynamic process. It is found that the bubble growth rate is determined by the evaporation rate at the entrance. Since the total evaporation flux is a constant, the predicted bubble growth rate is reversely proportional to the channel height, quantitatively consistent with the experimental results. Since most current studies for caviation are theoretical studies, our studies provide a new experimental approach to study these phenomena in artificial transparent nanochannel devices.
UR - http://www.scopus.com/inward/record.url?scp=84860524312&partnerID=8YFLogxK
U2 - 10.1115/IHTC14-23272
DO - 10.1115/IHTC14-23272
M3 - Conference contribution
AN - SCOPUS:84860524312
SN - 9780791849361
T3 - 2010 14th International Heat Transfer Conference, IHTC 14
SP - 697
EP - 702
BT - 2010 14th International Heat Transfer Conference, IHTC 14
Y2 - 8 August 2010 through 13 August 2010
ER -