A dual-scale turbulence model for gas–liquid bubbly flows  

气-液气泡流的双尺度湍动模型（英文）

作　　者：管小平 李兆奇 王丽军 李希 成有为 

机构地区：[1]College of Chemical and Biological Engineering,Zhejiang University

出　　处：《Chinese Journal of Chemical Engineering》2015年第11期1737-1745,共9页中国化学工程学报（英文版）

基　　金：Supported by the National Natural Science Foundation of China(U1162125,U1361112);the National High Technology Research and Development Program of China(2011AA05A205)

摘　　要：A dual-scale turbulence model is applied to simulate cocurrent upward gas-liquid bubbly flows and validated with available experimental data. In the model, liquid phase turbulence is split into shear-induced and bubble- induced turbulence. Single-phase standard k-e model is used to compute shear-induced turbulence and another transport equation is added to model bubble-induced turbulence. In the latter transport equation, energy loss due to interface drag is the production term, and the characteristic length of bubble-induced turbulence, simply the bubble diameter in this work, is introduced to model the dissipation term. The simulated results agree well with experimental data of the test cases and it is demonstrated that the proposed dual-scale turbulence model outperforms other models. Analysis of the predicted turbulence shows that the main part of turbulent kinetic en- ergy is the bubble-induced one while the shear-induced turbulent viscosity predominates within turbulent vis- cosity, especially at the pipe center. The underlying reason is the apparently different scales for the two kinds of turbulence production mechanisms： the shear-induced turbulence is on the scale of the whole pipe while the bubble-induced turbulence is on the scale of bubble diameter. Therefore, the model reflects the multi-scale phe- nomenon involved in gas-liquid bubbly flows.A dual-scale turbulence model is applied to simulate cocurrent upward gas-liquid bubbly flows and validated with available experimental data.In the model,liquid phase turbulence is split into shear-induced and bubbleinduced turbulence.Single-phase standard κ-ε model is used to compute shear-induced turbulence and another transport equation is added to model bubble-induced turbulence.In the latter transport equation,energy loss due to interface drag is the production term,and the characteristic length of bubble-induced turbulence,simply the bubble diameter in this work,is introduced to model the dissipation term.The simulated results agree well with experimental data of the test cases and it is demonstrated that the proposed dual-scale turbulence model outperforms other models.Analysis of the predicted turbulence shows that the main part of turbulent kinetic energy is the bubble-induced one while the shear-induced turbulent viscosity predominates within turbulent viscosity,especially at the pipe center.The underlying reason is the apparently different scales for the two kinds of turbulence production mechanisms:the shear-induced turbulence is on the scale of the whole pipe while the bubble-induced turbulence is on the scale of bubble diameter.Therefore,the model reflects the multi-scale phenomenon involved in gas-liquid bubbly flows.

关 键 词：Two-fluid modelDual-scale turbulence modelShear-induced turbulenceBubble-induced turbulenceBubbly flow 

分 类 号：O357.5[理学—流体力学] TN911.72[理学—力学]