Numerical Simulations of Cap-bubbly Flows Using Fluent
Knowledge of cap-bubbly flows is important to many industrial applications due to its role in the flow regime transition from bubbly flow to slug or churn-turbulent flow. One of the key characteristics of such flows is the existence of bubbles in different sizes and shapes associated with their distinctive dynamic natures. This important observation is however generally not well captured by many available two-phase flow models. In view of this, a modified two-phase three-field model is proposed, in which a two-group interfacial area transport equation (IATE) has been adopted to describe the dynamic changes of interfacial structure. In this approach, bubbles are categorized into two groups, I.e., spherical/distorted bubbles as Group-1 while cap/churn-turbulent bubbles as Group-2. Intra-and inter-group interactions resulting in bubble coalescence and disintegration, in addition to phase changes due to evaporation and condensation, contribute to the evolution of the interfacial structure and serve as the source and/or sink terms in the two-group IATE. Attention is paid to the appropriate constitutive relations of the interfacial transfers due to mechanical and thermal non-equilibrium between different fields. The proposed two-phase three-field model is used to predict the phase distributions of adiabatic air-water flows in a narrow rectangular duct. Good agreement between the simulation results from the proposed model and relevant experimental data indicates that the proposed model may be used as a reliable computational tool for two-phase flow simulations in such flow geometry.
Cap-bubbly flows two-group interfacial area transport equation interfacial area concentration two-phase three-field model
Xia Wang Xiaodong Sun
Nuclear Engineering Program, Department of Mechanical Engineering The Ohio State University 201 West 19th Avenue, Columbus, OH 43210
国际会议
上海
英文
2504-2522
2010-10-10（万方平台首次上网日期，不代表论文的发表时间）