An adiabatic experiment was conducted to investigate the effects of liquid properties on the characteristics
of two-phase flows in a horizontal circular microchannel. Distilled water and aqueous solutions of
ethanol were used as the test liquids. The ethanol concentration was varied to change the surface tension
and the viscosity. One of the four liquids together with nitrogen gas was injected through a T-junction
mixer to the test microchannel. Two mixers with different inner diameters of DM = 250 lm and
500 lm were used at a fixed microchannel diameter of D = 250 lm to study flow contraction effects at
the channel inlet. Bubble velocity data correlated with the drift flux model showed that the distribution
parameter, C0, increased with increasing of liquid viscosity and/or decreasing of surface tension, and C0
for flows with the contraction was higher. The pressure drop data correlated with the Lockhart–Martinelli
method showed that the two-phase friction multiplier, /2L
, for flows with the contraction was lower. From
data analysis, new correlations of C0 and /2L
were developed with some dimensionless numbers. On void
fraction prediction, two-fluid model code could predict well the data when an appropriate correlation of
interfacial friction force was used.