Advanced Ultrasound Techniques for Investigating Air-Water Two-Phase Flow: An Experimental Approach

The König-Project, funded by the German state, is a long-term project focused primarily on developing a multi-scale wave measurement laboratory to improve flow measurements in an industrial context. Part of this project researches the propagation of ultrasound waves inside a moving fluid. A wide variety of flow scenarios are considered, and new methods for ultrasonic flow measurement can be developed and optimized. One experimental scenario includes the determination of volume fraction and drop size distributions of air dispersed in water using ultrasonic waves.

For this purpose, a modular system is used as an initiative to integrate manufacturer-independent measurement components with open-source software for the acquisition and processing of ultrasound signals. The modular system equipment consists of a multichannel system, which allows the positioning of several transceivers to send and receive ultrasonic waves from different directions along the experimental zone of interest. The concentration of dispersed air in water will be determined by measuring the reduced transit time caused by the added compressibility of the air phase.

Characterizing multiphase flows using other techniques can be time-consuming and the accuracy can fall short as the complexity of the fluid grows. The use of ultrasound to characterize fluid flows has many advantages such: as a non-invasive method that doesn’t alter the fluid path, real-time data acquisition, and high-temporal resolution, it is cost-effective and can be used on opaque fluids. Therefore this technique is gaining more attention in several industrial applications, including oil and gas, hydrogen, and geothermal energy generation. The results of this investigation will be validated and compared with the output of a numerical simulation, in which the boundary conditions and the flow characteristics will be similar to the experimental setup.