Two-Phase Stereo-PIV measurement techniques for Gas-Liquid Two-Phase flow - Methodology and validation

The bubbles and three -component (3C) velocity are of great significance in the investigation of gas-liquid twophase flows. In this study, two kinds of two-phase stereo-PIV measurement techniques, based on optical phase discrimination and image phase discrimination, were proposed to realize the simultaneous measurement of 3C velocity and bubbles. The corresponding image processing and velocity reconstruction methods were developed. Three validation tests were conducted to verify the accuracy and feasibility of the proposed techniques. The measurement results of the pipe flow and the motor -driven swirl flow illustrate the sufficient accuracy of the techniques. Finally, the techniques were applied to the vertical bubbly pipe flow and the rising bubble in the bubble column. The results show that both OPD and IPD methods have successfully obtained the threedimensional velocity and bubbles. Through comparison, the IPD method was greatly recommended for twodimensional (2D) measurement due to its low equipment requirements, simple setups, and high spatial resolution.