Analysis of the characteristics of two-phase flow pattern in Y-shape mixed microchannel based on double coupled Duffing vibration simulation detection system

In this work, a visualization experiments were carried out in the Y-shape mixed rectangular microchannels with the hydraulic diameter of 133 μm at atmospheric pressure and at room temperature (25 °C). In the experiment, the range of inlet gas superficial velocities was 0.01-16.668 m/s, and the inlet liquid superficial velocity was 0.01-6.945 m/s. The main flow patterns observed in the experiments were slug flow, elongated slug flow, slug-annular transition flow, annular flow. Flow pattern maps were drawn according to the experimental data. Unlike the traditional friction resistance based rationalization for two phase flow patterns, this study relates the two-phase flow pattern mainly to the surface wettability of the material, the shape of the cross section and the hydraulic diameter of the microchannel. The new correlation presents the flow pattern transition boundary according to these three factors. In addition, the coupled Duffing vibration simulation system method is presented as a way to detect signals determining gas-liquid two-phase flow patterns and to analyze the flow characteristics. Based on the instantaneous oscillator velocity and displacement, we can deduce the underlying dynamics of two-phase flow patterns. The Duffing detection method can serve as a model for other nonlinear system analysis and other multi-phase flow characteristics analyses.