摘要

Two-phase pipe flow is investigated using two complementing experimental methods. The first measuring technique uses a wire-mesh sensor that allows obtaining instantaneous phase distribution in the pipe cross-section. This instrument also enables measuring instantaneous propagation velocities of the phase interface. The second method is a novel non-intrusive instrument based on a borescope connected to a digital video camera. Laser light sheet illumination makes it possible to obtain images in the illuminated pipe cross section only. Advantages and limitations of both measuring techniques for investigations of two-phase flows are examined. The wire-mesh sensor has a limited resolution and introduces a substantial disturbance to the flow. The borescope, on the othe hand, yield reliable results when a single phase exists between its lens and gas-liquid interface. In view of limitations of the borescope technique, stratified downward gas-liquid pipe flow is investigated here for a wide range of pipe inclinations and gas and liquid flow rates. A novel technique for processing the wire-mesh sensor data was developed to determine the instantaneous boundaries of gas-liquid interface. The wire-mesh-derived results based on application of the new algorithm are in a good agreement with the results obtained using the borescope. This agreement supports application of the wire-mesh sensors for studying gas-liquid flows for a wide range of flow conditions and in various flow patterns.