Flow patterns during boiling instability of deionized water across silicon-based microchannels with inner pin-fin arrays have been studied experimentally. Three types of microchannels with different pin-fin structures and a hydraulic diameter of 210 μm were used. During the unstable flow boiling, two types of instability modes of temperature and pressure oscillations occurred: long-period/large-amplitude oscillation mode and short-period/small-amplitude oscillation mode. There were increasing and decreasing stages of the temperature measurement during a period of long-period/large-amplitude oscillation mode. According to visualization observation, in the increasing stage of temperature oscillation for the in-line pin-fin microchannel, four two-phase flow patterns, including bubbly flow, vapor-slug flow, stratified flow, and stream flow, occurred sequentially with time; for the staggered pin-fin microchannels, the four two-phase flow patterns, together with single liquid-phase flow and single vapor-phase flow occurred sequentially with time. The flow pattern transitions were inverse between the increasing and decreasing stages of temperature measurement. Under the short-period/small-amplitude oscillation mode, only the stream flow occurred. With the increase of heat flux, the stream flow and the single vapor-phase flow occupied more and more time ratio during an oscillation period in the in-line and staggered pin-fin microchannels, respectively.
- Heat Transfer Division
Flow Patterns During Flow Boiling Instability in Silicon-Based Pin-Fin Microchannels
Xu, F, Wu, H, & Liu, Z. "Flow Patterns During Flow Boiling Instability in Silicon-Based Pin-Fin Microchannels." Proceedings of the ASME 2016 Heat Transfer Summer Conference collocated with the ASME 2016 Fluids Engineering Division Summer Meeting and the ASME 2016 14th International Conference on Nanochannels, Microchannels, and Minichannels. Volume 2: Heat Transfer in Multiphase Systems; Gas Turbine Heat Transfer; Manufacturing and Materials Processing; Heat Transfer in Electronic Equipment; Heat and Mass Transfer in Biotechnology; Heat Transfer Under Extreme Conditions; Computational Heat Transfer; Heat Transfer Visualization Gallery; General Papers on Heat Transfer; Multiphase Flow and Heat Transfer; Transport Phenomena in Manufacturing and Materials Processing. Washington, DC, USA. July 10–14, 2016. V002T08A003. ASME. https://doi.org/10.1115/HT2016-7387
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