Gas-liquid two-phase flow splitting at microchannel junctions with different branch angles

In the present work, the phase split occurring at microchannel junctions with the square cross-section of 0.5×0.5 mm2 was investigated experimentally under adiabatic condition. Microchannel junctions with five different branch angles varying from 30° to 150° were manufactured. Two different methods of controlling gas/liquid division from the run/the branch were employed, suitable for acquiring splitting data for a wide range of flow patterns covering slug flow, slug-annular flow and annular flow. The inlet superficial velocities varied from 0.8 to 21.3 m/s for gas phase (nitrogen), and from 0.019 to 0.356 m/s for liquid phase (pure water). The high speed recording technique was utilized to elucidate the fluid dynamics of two-phase flow splitting at microchannel junctions. Data analysis revealed that the phase splitting curves did not simply take on a transitional characteristic when the inlet flow pattern changed from slug flow to annular flow. Furthermore, the liquid taken off from the branch did not decrease with increasing branch angle for all kinds of inlet flow patterns. Finally, by comparing the present data with those of mini- and macro-scale research, it was found that more liquid was taken off from the branch at microchannel junctions.