Water Holdup Measurement in Oil–Water Flows With Staggered Double Helix Microwave Sensor

To realize high-resolution and stable water holdup measurement of oil–water flows with varying water salinity, this article presents a noninvasive staggered double helix microwave sensor (SDHMS). The staggered double helix structure makes the${E}$-fields to rotate and distribute well inside the pipe, which has the potential to overcome the negative influence of the complicated distribution of oil droplets in oil–water flows. First, the phase–frequency characteristic of the SDHMS changed with water holdup at 1 GHz is investigated via the finite-element method. Then, the SDHMS prototype is realized by using a very low-cost method. And, an industrial flow loop test of vertical upward oil–water flows is carried out to evaluate the complete characterization of the SDHMS. And, the phase output versus with mixture velocity and water cut in different water salinity is obtained. It shows that the SDHMS has a good sensitivity for measuring water holdup in oil–water flows with the consideration of salinity. Finally, a dynamic water holdup model is established through a decoupling method.