*Article* **Investigation of Plume O** ff**set Characteristics in Bubble Columns by Euler–Euler Simulation**

#### **Yixuan Cheng 1, Qiong Zhang 1,2, Pan Jiang 1, Kaidi Zhang 1 and Wei Wei 1,\***


Received: 16 June 2020; Accepted: 6 July 2020; Published: 7 July 2020

**Abstract:** Based on low-cost and easy to enlarge, the bubble column device has been widely concerned in chemical industry. This paper focuses on bubble plumes in laboratory-scale three-dimensional rectangular air-water columns. Static behavior has been investigated in many experiments and simulations, and our present investigations consider the dynamic behavior of bubble plume offset in three dimensions. The investigations are conducted with a set of closure models by the Euler–Euler approach, and subsequently, literature data for rectangular bubble columns are analyzed for comparison purposes. Moreover, the transient evolution characteristics of the bubble plume in the bubble column and the gas phase distribution in sections are introduced, and the o ffset characteristics and the oscillation period of the plume are analyzed. In addition, the distributions of the vector diagram of velocity and vortex intensity in the domain are given. The e ffects of di fferent fluxes and column aspect ratios on bubble plumes are studied, and the o ffset and plume oscillation period (POP) characteristics of bubbles are examined. The investigations reveal quantitative correlations of operating conditions (gas volume flux) and aspect ratios that have not been reported so far, and the simulated and experimental POP results agree well. An interesting phenomenon is that POP does not occur under conditions of a high flux and aspect ratio, and the corresponding prediction values for the conditions with and without POP are given as well. The results reported in this paper may open up a new way for further study of the mass transfer of bubble plumes and development of chemical equipment.

**Keywords:** CFD; bubble plume; oscillation and o ffset characteristic; bubble; gas–liquid flow
