Flow Parameter Measurement of Intermittent Flow by PIV Interface Imaging Characteristics

Gas–liquid intermittent flow characteristics in horizontal pipelines pose challenges to pipeline systems. Therefore, particle image velocimetry (PIV) and high-speed photography are utilized to investigate the gas–liquid intermittent flow in a 15-mm horizontal pipeline. In addition to velocity measurements, the appearance of dual-layer gas–liquid interfaces during image acquisition enables the 3-D reconstruction of gas–liquid interfaces. First, sophisticated image processing algorithms are applied to identify the real and virtual gas–liquid interfaces. Flow characteristics are analyzed based on the distribution of gas–liquid interfaces and the liquid velocity field. The spatial positions of these two gas–liquid interfaces are then located and fit to determine gas–liquid interface contours. Consideration of temporal evolution aids in the reconstruction of a dynamic 3-D representation, evaluating the gas volume holdup. Validation involving liquid superficial velocity shows that the relative error in gas volume holdup is below 10%. This approach effectively visualizes intermittent flow characteristics and reconstructs the gas–liquid interface.