Void fraction of nitrogen-water flow in flat microchannels

In this study, we investigated a behavior of time-averaged void fraction in five flat microchannels with cross sectional area of 0.05x10, 0.09x10, 0.15x10, 0.05x20 and 0.15x20 mm². The experiments have been conducted at fixed superficial velocity of liquid phase. The dependence between time-averaged void fraction and superficial gas velocity has been studied. It was shown, that this dependence may be approximate by power law with R²=0.968. The dependence between time-averaged void fraction and homogeneous void fraction has been investigated. It was shown that the height of channel has not been affected by void fraction behavior, however the width of channel has influence: with an increasing of the channel width the dependence line shifts towards lager homogeneous fractions. However to take into account the influence of the channel width on surface area occupied by gas and to generalize data further investigations are required. (paper)