Mechanism of transition from elongated bubbles to wavy-annular regime in flow boiling through microchannels

نویسندگان

چکیده

Transition from elongated bubbles to annular flow regime is one of the most intricate phenomena in boiling microchannels. To identify this transition, maps have been introduced primarily based on visualizations and characterized using average properties. However, understanding mechanism responsible for transition demands accurate determination hydrodynamic characteristics liquid films around vapor core. But, challenges associated with measurements thickness velocity made it difficult determine hydrodynamics. Here, we utilize a measurement technique film along velocities two phases. These enabled calculation cross-sectional void fraction, quality, interfacial shear stress superficial velocities, which form coordinates existing maps. The results show that upon regime, remarkable increase occurs due substantial liquid-vapor stress. This stress, function thickness, velocity, channel aspect ratio, as criterion (EB) wavy-annular (WA) regime.

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ژورنال

عنوان ژورنال: International Journal of Heat and Mass Transfer

سال: 2021

ISSN: ['1879-2189', '0017-9310']

DOI: https://doi.org/10.1016/j.ijheatmasstransfer.2021.121464