The bubble shape affects the gas-liquid interface momentum, heat and mass transfer, as well as the flow field around the bubble. Correctly predicting the bubble shape is challenging but indispensable under bubble swarm conditions. In this work, the bubble aspect ratio, which is adopted for the characterization of the bubble shape, is obtained through high-speed photography combined with an image processing algorithm from several experiments with an oscillating bubble plume. The results show that the bubble aspect ratio tends to be a constant value with increasing the bubble diameter, rather than decreasing as predicted by various empirical correlations developed in single bubble experiments. None of the available empirical correlations can accurately correlate the bubble aspect ratio with Weber number or Tadaki number. Among the available correlations in literature, Eo based correlation proposed by Besagni and Inzoli (2016) and Eo-Re based correlation proposed by Besagni and Deen (2020) show a better performance. The predicted values of Eo-Re based correlation developed in this work are the closest to the experimental data compared with others.

气泡的形状会影响气液界面的动量，热量和质量的传递以及气泡周围的流场。正确预测气泡形状具有挑战性，但在气泡群条件下必不可少。在这项工作中，通过高速摄影结合图像处理算法，通过多次振荡气泡羽流的实验，获得了用于表征气泡形状的气泡纵横比。结果表明，气泡长宽比随着气泡直径的增加而趋于为恒定值，而不是如单个气泡实验中开发的各种经验相关性所预测的那样减小。没有可用的经验相关性可以将气泡长宽比与Weber数或Tadaki数精确相关。EO通过Besagni和Inzoli（2016），并提出基于相关EO-再根据相关的Besagni和迪恩（2020）提出的表现出更好的性能。与其他数据相比，这项工作中开发的基于Eo-Re的相关性的预测值最接近实验数据。