Disagreement between the results of void fraction in microchannels
obtained by different investigators, was discussed by
Ide et al. [24]. They addressed the differences in gas–liquid twophase
flow characteristics that occur in conventional size channels
and micro-channels by examining the two-phase flow pattern,
interfacial wave, void fraction and friction pressure drop data obtained
in circular and rectangular channels with a hydraulic diameter
ranging from 50 lm to 6.0 mm. Two different inlet sections
were covered in micro-channel experiments, a gradually reducing
section and a T-junction. The void fraction data obtained in microchannels
and conventional size channels showed significant differences
depending on the channel cross-section and inlet geometry.
For the micro-channel with a diameter of 100 lm, the effects of the
inlet geometry and gas–liquid mixing method on the void fraction
were seen to be quite strong, while the conventional size channels
have shown a much smaller effect of inlet geometry on the void
fraction.