MATHEMATICAL MODEL OF TWO-PHASE FLOWS
MATHEMATICAL MODEL OF TWO-PHASE FLOWS
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两相流的数学模型
DOI：
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发表时间：
2001
期刊：
影响因子：
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通讯作者：
J. Brada
中科院分区：
文献类型：
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作者：
J. Brada
给出了两相混合物流动和温度的二维动力学模型及其数值模拟结果。混合物由不可压缩的粘性液体和分散的固体颗粒组成。该模型的方程是利用假设构造的，这些假设降低了众所周知的两相流的复杂性，使得能够使用标准的计算技术，并且允许获得整个混合物的一个方程。这些假设例如没有相变、低体积分数的颗粒或它们的直径较小。该模型包含了液固两相流动的连续性和N-S方程。此外，还包括了混合物的热焓和固相体积分数的标量方程。液相的Navier-Stokes方程中含有一个受温度梯度影响的浮力项，而固相的Navier-Stokes方程中的浮力项描述了浓度梯度的影响。混合物的纳维斯托克斯方程和连续性方程是从它们的单相等价物导出的。流动方程和两个标量方程均采用通用有限体积法求解。数值计算结果与室内试验结果的对比令人满意，这使得所使用的一些技术能够应用于三维模型。
Two-dimensional dynamic model of the flow and temperature in two -phase mixtures and results of its numerical simulations are presented. Mixtures consist of an incompressibl e viscous liquid and dispersed solid particles. Equations of the model are constructed using assumptions that decrease well-known complexity of two-phase flows, enable to use standard computational techniques and allow obtaining one equation for the whole mixture. These assumptions are e.g. no phase changes, low volume fraction of particles or their small diameter. The model contains the continuity and the Navier-Stokes equations of the flow for both liquid and solid phase. Further, scalar equations for enthalpy of the mixture and volume fraction of the solid phase are included. The Navier-Stokes equation for the liquid phase contains a buoyancy term with the influence of temperature gradients, while the buoyancy term in the Navier-Stokes equation for the solid phase describes the influence of concentration gradients. The Navier-Stokes and the continuity equation for the mixture are derived from their single-phase equivalents. The flow equation and both scalar equations are solved using a general finite-volume method. Comparison of numerical calculations and results of laboratory experiments showed satisfactory agreement, which enables to apply some of the used techniques in three-dimensional models.