Hydrodynamics features of dispersed bubbles in the ventilated wake flow of a cylinder

作     者：Ning Mao Can Kang Wisdom Opare Yang Zhu 

作者机构：School of Energy and Power Engineering Jiangsu University Faculty of Engineering Takoradi Technical University 

出 版 物：《Chinese Journal of Chemical Engineering》 (中国化学工程学报（英文版）)

年 卷 期：2018年第26卷第9期

页      面：1803-1813页

核心收录：

学科分类：081704[工学-应用化学] 08[工学] 0817[工学-化学工程与技术] 081701[工学-化学工程] 

基　　金：Supported by the National Natural Science Foundation of China(51676087) 

主　　题：Bubble Ventilation Wake flow PIV Photography Bubble size distribution 

摘      要：An experimental study was conducted to investigate the 2 D bubbly flow downstream of a cylinder. Sparsely distributed bubbles were produced using the ventilation method. The carrier flow was measured using the particle image velocimetry(PIV) technique. The shadow imaging technique was used to capture instantaneous bubbly flow images. An image-processing code was compiled to identify bubbles in acquired image, calculate the bubble equivalent diameter and the bubble velocity. The effects of Reynolds number and the flow rate of the injected air were considered. The result indicates that the carrier flow is featured by distinct flow structures and the wake region is suppressed as the upstream velocity increases. Regarding the bubbles trapped in the wake flow, the number of small bubbles increases with the upstream velocity. On the whole, the bubble velocity is slightly lower than that of the carrier flow. The consistency between small bubbles and the carrier flow is high in terms of velocity magnitude, which is justified near the wake edge. The difference between the bubble velocity and the carrier flow velocity is remarkable near the wake centerline. For certain Reynolds number, with the increase in the air flow rate, the bubble equivalent diameter increases and the bubble void fraction is elevated.