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基于将颗粒脉动分成湍流引起的大尺度脉动和颗粒间碰撞产生的小尺度脉动的概念,用统一的方法处理两类脉动,建立了稠密两相流动的双尺度二阶矩两相湍流模型。用该模型对下行床内稠密两相流动进行了数值模拟。模拟结果和实验结果符合,和考虑碰撞的单尺度二阶矩湍流模型的结果接近,比其有一定程度的改进。结果表明,由于颗粒的碰撞,小尺度脉动也呈一定程度的各向异性,而且小尺度脉动和大尺度脉动在大部分区域内减小,而在接近壁面处增大。
Based on the concept of large-scale pulsation caused by turbulence of particles and small-scale pulsation caused by collision between particles, two types of pulsations are treated in a uniform way and a two-scale second-order moment and two-phase turbulence model of dense two-phase flow is established. The model is used to simulate the dense two-phase flow in the down-going bed. The simulation results are in good agreement with the experimental results, which are close to the results of the single-scale second-moment turbulence model considering the collision, which is improved to a certain extent. The results show that due to the collision of particles, the small-scale pulsations also show a certain degree of anisotropy, and the small-scale and large-scale fluctuations decrease in most areas and increase near the wall.