Combined volumetric PIV-LIF measurements of the correlation between bubble cluster dyxnamics and mixing in a co-moving frame of a stable/unstable bubble plume

反应鼓泡塔中气泡的动力学相互作用和团簇的形成对混合有重要影响。这是由于气泡尺寸的局部尺度上的流体动力学不稳定性（尾流不稳定性、气泡-气泡相互作用、形状变化和升力变化）。在鼓泡塔中，气泡诱导的湍流占主导地位，这些过程是混合的驱动力.相关的影响传质的相应的关联式还不存在。为了研究这些过程，使用具有脉冲气体分布器的大型旋转泡罩塔（DN 500，高度5 m），其中在羽流（N 10-50个气泡的簇）的上升期间在同向移动框架中观察到这样的簇中的局部动力学。本研究的目的是通过组合的3D-PIV/LIF测量技术，在同一子体积内同时检测体积流场和浓度场，并对簇进行时间跟踪。 实验技术也适用于提供边界条件，用于高分辨率DNS / LES模拟的流动气泡簇（N < 50）在一个所谓的周期性的盒子。因此，可以与最高人民检察院各工作组进行直接的数量比较。 根据结果，一个合适的传输模型是派生，其中考虑到当地集群动态。在围绕垂直轴旋转的背景运动的影响下，也进行了实验的气泡群，以调查在群中的螺旋不稳定性的效果。

Dynamic interaction of bubbles and cluster formation in swarms have a significant influence on the mixing in reactive bubble columns. These are due to hydrodynamic instabilities on the local scale of the bubble size (wake instabilities , bubble-bubble interaction , change in shape and change of lift forces). In bubble columns where bubble- induced turbulence is dominant these processes are the driving force for mixing. Corresponding correlations of the associated impact on the mass transfer do not exist yet. To investigate these processes a large rotating bubble column (DN 500 , Height 5m) is used with a pulsed gas sparger, where the local dynamics in such a cluster are observed in the co-moving frame during the rise of the plume (cluster of N 10-50 bubbles). The aim of this study is to detect the volumetric flow and concentration field simultaneous within the same sub-volume with temporal tracking of the cluster via combined 3D-PIV/LIF measurement technique. The experimental technique is also adapted to provide boundary conditions as used in high-resolution DNS / LES simulations of flow bubble clusters ( N < 50 ) in a so-called periodic box. Thus a direct quantitative comparison is possible with various working groups in the SPP. Based on the results a suitable transport model is to be derived , which takes into account the local cluster dynamics. The experiments on the bubble swarms are carried out also under the influence of a rotating background motion around the vertical axis in order to investigate the effect of helical instabilities in the swarm.