Ultraschallbasierte Messung der Strömungsgeschwindigkeit von Flüssigkeiten und Gasen für den Einsatz in Drainageleitungen in Tunneln

A train passing a tunnel can cause a strong pressure wave, depending on its speed. Under disadvantageous conditions, this can adversely affect the athmospheric environment of the tunnel drainage. In order to investigate this, a measuring system is needed that measures the flow conditions in the drainage pipe for both air and water with high temporal resolution. Since railway tunnels usually have a very low gradient, the effect of the pressure wave can cause a critical reversal of the air flow direction. This can also reverse the flow direction of the water. In this contribution, an ultrasound-based measuring system is presented, which allows the simultaneous measurement of the air and water flow velocities and directions. It is based on the transit time difference method and is suitable for detecting flow velocities ranging from cm/s to m/s. The setup of the measuring system is presented and its performance is then shown on the basis of measured data.