Investigation on Two-phase Flow Dynamics with Discrete Bubble Model
Investigation on Two-phase Flow Dynamics with Discrete Bubble Model
复制标题
用离散气泡模型研究两相流动力学
DOI：
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发表时间：
2008
影响因子：
7.4
通讯作者：
M. Shoji
中科院分区：
文献类型：
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作者：
Takeyuki Ami;H. Umekawa;M. Ozawa;M. Shoji
传统的模型包括漂移通量模型和双流体模型都是基于“连续流假设”，通过时间平均来构造的，因此两个相都是在每个时空空间中定义的。这使得它可以适用于各种两相流动力学，而固有的空隙率波动，通常观察到的段塞流和搅拌流，很难模拟。为了突破时间平均法带来的这一难题，发展了基于一维质量守恒方程的离散气泡模型，即气泡传播方程。该模型考虑了气泡尾流效应、局部压力脉动、气相可压缩性以及几何约束引起的相重分布等动量效应。所得含气率的时空波动特性不仅能很好地模拟定常流中固有的两相特性，而且能很好地模拟振荡流中固有的两相特性。
Conventional modeling including drift-flux model and two-fluid model is based on “continuous flow hypothesis”, being constructed by time-averaging, and thus both phases are defined in every spatio-temporal space. This makes it possible to apply to a variety of two-phase flow dynamics, while the intrinsic void fraction fluctuations, typically observed in slug and churn flows, are hardly simulated. In order to break through such a problem caused by time-averaging, discrete bubble model based on one-dimensional mass conservation equation, i.e. void propagation equation, has been developed. This model takes into account, as momentum effects, the wake effect induced by preceding bubbles, the local pressure fluctuation and the compressibility of gas phase together with the phase re-distribution due to geometrical constrains. Thus obtained spatio-temporal fluctuation characteristics of void fraction well simulated inherent two-phase behavior not only in a steady flow but also in an oscillatory flow.