Geometric and dynamic characteristics of bubbles in cross-flow
PANG Chunbo1, YUAN Shouqi2*
1. School of Energy and Power Engineering, Jiangsu University, Zhengjiang, Jiangsu 212013, China; 2. National Research Center of Pumps, Jiangsu University, Zhenjiang, Jiangsu 212013, China
Abstract:To study the geometric and dynamic characteristics of bubbles in cross-flow, air was injected into the circulating water tunnel to produce bubbles. The high-speed photography was used to record the shape and evolution of bubbles. An algorithm was developed based on MATLAB to extract characteristic bubble parameters from the acquired images. The trajectory, stress analysis,rising angle, bubble shape, bubble size and shedding frequency were analyzed. The linear relationship between the bubble terminal velocity and the equivalent bubble diameter was described. Based on a non-dimensional analysis, the bubble aspect ratio was associated with Weber number. The results show that the bubble movement tra-jectory is similar to that in the hydrostatic environment, which is divided into straight line segment and oscillation segment. The rising angle changes sinusoically and becomes gradually stable with the increase of Reynolds number.With the rise of water flow velocity, the trajectory gradually inclines to a straight line and the oscillation amplitude decreases. The final velocity of the bubble decreases rapidly with the increase of the equivalent diameter and the velocity of the small bubble rises rapidly. The correlation between bubble deformation and surface tension at high Reynolds number can be ignored.
庞春波,袁寿其*. 气泡在横流中的几何及动力学特性[J]. 排灌机械工程学报, 2020, 38(10): 1023-1029.
PANG Chunbo,YUAN Shouqi*. Geometric and dynamic characteristics of bubbles in cross-flow. Journal of Drainage and Irrigation Machinery Engin, 2020, 38(10): 1023-1029.