Abstract:

The study of gas-solid flow of slender particles is one of the key issues of that of gas-solid two-phase flow. The modeling of motion and force of slender particles in a flow field and the establishment of two-way coupling relation between slender particles and flow field are one of the key researches of gas-solid flow of slender particles. In this paper, on the basis of earlier created models of motion and force of slender particles based on rigid dynamics, in combination with the coupling correlation between Lagrangian time scales and κ-ε model, and with the modified inter-slender particle collision model, a high Reynolds number semi-dense or dense gas-solid multi-way coupling model of slender particles was established. A gas-solid two-phase flow field of slender particles in a riser was simulated using this model. It was shown that there is an evident randomness on the residence positions of slender particles in a riser at different time. The residence of slender particles resulted in the evident decline of pressure and velocity of local flow field. It was also found that there was an evident orientation selectivity of slender particles in the process of fluidization.

Key words: gas-solid two-phase flow of slender particles, riser, modeling, multi-way coupling, numerical simulation

摘要：

细长颗粒气固两相流研究已成为气固两相流研究的重点问题之一。而各种细长颗粒在流场中的受力、运动模型构建以及细长颗粒/流场间的耦合关系的构建是细长颗粒两相流数值模拟研究的难点之一。在已经基于刚体动力学原理构建了细长粒子气固两相流单向耦合模型的基础上,结合基于κ-ε模型的球形粒子-流场气固间耦合关联式,并改进细长颗粒间碰撞模型,从而构建了细长颗粒气固两相流动多向耦合数值模拟平台。并且采用此平台对某一实际流化床内的细长粒子气固两相流场进行了数值模拟研究。研究表明,不同时间细长颗粒在流场内的停留位置具有较强的随机性;细长颗粒在流化运动过程中伴随有较明显的取向选择性;细长颗粒的存在会导致当地流场的速度、压强均有较为明显的下降。

关键词: 细长颗粒气固两相流, 提升管, 建模, 多向耦合, 数值模拟