Flow Pattern Identification of Gas–Liquid Two-Phase Flow Based on Capacitively Coupled Contactless Conductivity Detection

Based on a capacitively coupled contactless conductivity detection technique, a new method for the online flow pattern identification of gas-liquid two-phase flow is proposed. This paper includes two parts: First, a new sensor (the single-shield sensor), which is suitable for the parameter measurement of gas-liquid two-phase flow, is developed, and second, with the developed single-shield sensor, the flow pattern identification of gas-liquid two-phase flow is studied by combining the wavelet analysis technique and the support vector machine technique. The experimental results show that the developed single-shield sensor is successful. It has the advantages of low cost, simpler construction, better stability, and better measurement performance. The experimental results also indicate that the proposed flow pattern identification method is effective, and the identification accuracy results are satisfactory. In five different pipes (the inner diameters are 1.8, 2.8, 4, 6.1, and 7.8 mm, respectively), the identification accuracy results for typical flow patterns (stratified, wavy, bubbly, slug, and annular flow) are all above 91%. This paper verifies that is a promising technique for flow pattern identification of gas-liquid two-phase flow, and it may have a broad perspective in related industrial field.

I. Introduction

GAS–LIQUID two-phase flow systems widely exist in many industries, such as chemical, pharmaceutical, petroleum, energy, power engineering, etc. Reliable identification of the flow patterns of gas–liquid two-phase flow is very important for the heat and mass transfer efficiency, the pressure drop estimation, and the measurement of other parameters of two-phase flow systems. Due to the complexity of gas–liquid two-phase flow, the existing flow pattern identification methods cannot fulfill the growing requirements of industrial applications and mechanism studies [1]–[3].