Pattern identification of kerosene-water two-phase flow in Y-shaped microchannels using terahertz spectroscopy

Abstract

In this paper, the terahertz time-domain spectroscopy (THz-TDS) is proposed to investigate the behavior underlying kerosene-water two-phase flow in Y-shaped rectangular microchannels. The microchannel is initially saturated with water and water forms an external continuous phase at low kerosene flow velocities (vk), while a dispersed phase is formed at high vk. The flow process of kerosene-water two-phase flow in microchannel was in situ monitored using a THz-TDS peak intensity, and four flow patterns such as droplet flow, plug flow, slug flow and deformed interface flow are identified over a wide range of vk from 2.08 to 43.13 cm/s at selected water flow velocity (vw) of 13.96 cm/s and 27.71 cm/s. Due to the strong dependence of flow patterns on the vw, only droplet, plug and slug flows are observed at high vw. In addition, with the vw increasing from13.96 cm/s to 27.71 cm/s the ranges of vk for droplet flow and plug flow patterns are expended by ∼100%. A parameter β = k/vw, where k is the slop of the peak intensity of THz-TDS against vk, was proposed to characterize the kerosene-water two-phase flow patterns, and each β only corresponded to one phase for various vk at different vw. These results render THz-TDS a feasible technology for investigating the behavior of oil-water two-phase flow inside microfluidic devices and lay the foundation for experimental and numerical investigations on multiphase flow in microchannels for further study.