Void Fraction, Wall and Interfacial Friction Forces for Two-Phase Flow in Microchannel

Abstract

The flow characteristics of the two-phase flows in a 100 µm circular horizontal microchannel have been investigated experimentally and analytically. In the experiments, nitrogen gas and one of four liquids (distilled water and 4.8, 49, 100 wt% ethanol in water) were injected through a T-junction type mixer to the microchannel, having smaller diameter than that of the mixer. Both quasi-homogeneous flow and quasi-separated flow was observed depending on gas and liquid flow conditions. Furthermore, the data on void faction, frictional pressure drop and interfacial friction force were found to be larger in the quasi-homogeneous flow than the quasi-separated one. In the analysis, empirical correlations of the liquid-wall friction force and the gas-liquid interfacial friction force were developed respectively for the quasi-homogeneous and the quasi-separated flows. By substituting these correlations into an analytical code based on a one-dimensional two-fluid model, we calculated the void fraction. The calculations reasonably agreed with the data irrespective of the quasi-homogeneous and the quasi-separated ones.