Size and shape effects on two-phase flow instabilities in microchannels

Man Lee, Yiu Yan Wong, Man Wong, Yitshak Zohar

Research output: Contribution to journalConference articlepeer-review

4 Scopus citations


An integrated microchannel heat sink consisting of shallow, trapezoidal microchannels has been fabricated using standard micromachining techniques to highlight the effects of the micrometer sized channel shape on the evolving flow patterns and, consequently, on the thermal response of the system. An integrated heater provides the local heat source, while an array of temperature microsensors is used for temperature distribution measurements. DI water, serving as the working fluid, is pressurized through the microchannels for forced heat convection. Temperature plateaus are observed in the boiling curves, corresponding to the latent heat of phase change of the working fluid from liquid to vapor phase. The evolving two-phase flow patterns have been recorded and analyzed using high-speed camera. Bubble formation, growth and detachment at specific nucleation sites have been observed. Annular flow mode has been found to be unstable in trapezoidal channels. Instead, a highly unsteady transition region from upstream vapor phase to downstream liquid phase flow is developed, and the average location of this region depends on the input power.

Original languageEnglish (US)
Pages (from-to)28-31
Number of pages4
JournalProceedings of the IEEE Micro Electro Mechanical Systems (MEMS)
StatePublished - 2002
Externally publishedYes
Event15th IEEE International Conference on Micro Electro Mechanical Systems MEMS 2002 - Las Vegas, NV, United States
Duration: Jan 20 2002Jan 24 2002

ASJC Scopus subject areas

  • Control and Systems Engineering
  • Mechanical Engineering
  • Electrical and Electronic Engineering


Dive into the research topics of 'Size and shape effects on two-phase flow instabilities in microchannels'. Together they form a unique fingerprint.

Cite this