Volumetric Reconstruction of Taylor Slug Gas Flow Using IR Transceiver in Minichannels

Taylor slug flow commonly occurs in crude oil pipelines, mini-/microreactors, space propulsion thrusters, heat exchangers, and nuclear reactors. The flow is an intermittent gas regime which occurs in flowing liquid inside pipelines and capillary tubes. Measurement of liquid-film thickness and cross-sectional and volumetric void fraction is necessary for an effective operation and safety of many industrial processes involving heat and mass transfer operations. In industrial applications such as miniheat exchangers, lab-on-chip devices, and pulsating heat pipes, gas-liquid Taylor flow enhances heat and mass transfer. The dominance of surface tension force is responsible for the occurrence of Taylor flow. Online measurement of void fraction is essential to determine heat and mass transfer characteristics of systems involving the two-phase flow. This article focuses on developing an instrumentation technique for the measurement of volumetric voids in minichannels. The effect of thickness of liquid films and nose/tail shape on infrared (IR) transceiver irradiation is studied. The experiments are done in two borosilicate glass tubes (3.40 and 1.50 mm inner diameter and 0.6 and 2.5 mm thickness, respectively) to measure liquid-film thickness and volumetric void fraction using a pair of IR transceiver. A numerical model is developed using COMSOL Multiphysics for the same experimental conditions. The effect of nose/tail curvature shape and liquid-film thickness on volumetric void fraction is predicted using a novel simple algorithm. A 3-D reconstruction technique is developed by measuring the undulations at the sides and top/bottom of the Taylor slug using a pair of IR transceiver output current (mA).