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

作者：Guan, Xiaoping; Li, Zhaoqi; Wang, Lijun^*; Li, Xi; Cheng, Youwei

来源：Chinese Journal of Chemical Engineering, 2015, 23(11): 1737-1745.

DOI：10.1016/j.cjche.2015.09.003

• Two-fluid model
• Dual-scale turbulence model
• Shear-induced turbulence
• Bubble-induced turbulence
• Bubbly flow

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-epsilon 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 themain 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.

• 出版日期2015-11
• 单位浙江大学