Flow regime identification of gas liquid two phase flow in vertical tube with small diameter

A helical capacitance sensor was developed to measure the void fraction and identity the flow regime of the gas-liquid two-phase flow in a vertical tube with a small diameter. Two sensors were designed for different pipes with the diameter of 5.0 and 2.4mm respectively. The time series, the probability density function (PDF) and the higher-order spectrum of the void fraction were used to identify the flow regimes including bubble flow, slug flow, transitional flow and annular flow. The three methods can identify the flow regimes efficiently according to the different characteristics of the gas-liquid two phase flow.