A Void Fraction Measurement Method of Gas-water Flow Based on Microwave Method

In the natural gas industry, measuring void fraction with high accuracy is challenging, because the flow pattern of gas-flow is complicated and changeable. This research presents a microwave sensor to measure void fraction of gas-water flow based on the microwave transmission line method. The sensor contains horizontal and vertical electrodes resulting in a spatial orthogonal transmission line combination structure, so that the gas-water flow regime can be detected and its influence on the measurement can be accounted for. The electromagnetic fields inside the sensor for stratified and annular distribution structure are simulated and analyzed using COMSOL software. Furthermore, the variation characteristics of the horizontal and vertical electrode phase outputs of the stratified distribution structure are investigated by static experiments. Finally, flow experiments covering stratified, wavy, slug, annular gas-water flow regimes, indicates that the void fraction are positive correlated to the sensor outputs and can be predict by the sensor.