Study on Coupling Effect and Dynamic Behavior of Double Bubbles Rising Process

Abstract

AbstractGas-liquid two-phase flow widely exists in nuclear energy engineering, in which bubble movement and deformation are critical problems. Because the activity of bubbles in the fluid is a very complex physical process, and the movement process is a flow field-bubble coupling process, which has strong nonlinearity and unsteady, the relevant research is usually based on experiments and simulation.We built a medium-sized experimental device to generate double bubbles with different sizes and characteristic numbers and recorded the motion trajectory with a high-speed camera. We developed and improved the image processing method to obtain high-quality bubble motion information and realized a good capture of bubble shape and rotation.The experimental results show that in the two bubbles rising successively, the trailing bubble is affected by the trailing field of the leading bubble, and the bubble velocity, relative distance, deformation rate, and other parameters change accordingly. In addition, through simulation, we get the interaction mechanism of the bubbles under experimental conditions. The results show that the coupling leads to flow field velocity and pressure changes, which explains the experimental results. The research results are helpful for a thorough understanding of the law of bubble movement and provide empirical data support for developing a thermal-hydraulic model.