Bubble dynamics in microchannels. Part I: single microchannel

• Published in: International journal of heat and mass transfer 2004-12, Vol.47 (25), p.5575-5589
• Main Authors: Lee, P.C., Tseng, F.G., Pan, Chin
• Format: Article
• Language: English
• Subjects: Applied sciences; Boiling heat transfer; Bubble dynamics; Electronics; Exact sciences and technology; Micro- and nanoelectromechanical devices (mems/nems); Microchannel; Onset nucleate boiling; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices
• ISSN: 0017-9310; 1879-2189
• DOI: 10.1016/j.ijheatmasstransfer.2004.02.031

The present work explores experimentally bubble dynamics in a single trapezoid microchannel with a hydraulic diameter of 41.3 μm. The fabrication process of the microchannel employs a silicon bulk micromachining and anodic bounding process. Bubble nucleation, growth, departure size, and frequency are observed using a high speed digital camera and analyzed by the Image-Pro. The results of the study indicates that the bubble nucleation in the microchannel may be predicted from the classical model with microsized cavities and the bubble typically grows with a constant rate from 0.13 to 7.08 μm/ms. Some cases demonstrate an extraordinarily high growth rate from 72.8 to 95.2 μm/ms. The size of bubble departure from the microchannel wall is found to be governed by surface tension and drag of bulk flow and may be fairly correlated by a modified form of Levy equation. The bubble frequency in the microchannel is comparable to that in an ordinary sized channel. The traditional form of frequency–departure-diameter relationship seems to be inexistent in the microchannel of this study.