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Study on the Control of Meso-Scale Particle Structure formed in Gas-Solid Flow

气固流中细观颗粒结构的控制研究

基本信息

批准号：
13650181
负责人：
TANAKA Toshitsugu
金额：
$ 2.3万
依托单位：
Osaka University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2001
资助国家：
日本
起止时间：
2001 至 2002
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-13650181/
关键词：
Multiphase Flow Gas-Solid Flow Meso-Scale Structure Particle Cluster Numerical Simulation Experiment

项目摘要

To make the basic study for the flow control of clustering flows the effects of particle size distribution on the structure of the clustering flow is studied. Numerical simulations are performed for the gas-solid flows in a rectangular-parallelepiped calculation domain surrounded by periodic boundaries. The fluid motion is calculated by using DNS, while, the solid flow is calculated by using a Lagrangian model with considering the particle-particle collision. Furthermore, an experiment on the granular sedimentation flows in a vertical duct is performed to measure the structure of particle clusters and to validate the present simulation. In the experiment, the spatial structure of clusters are measured by a laser-sheet visualization equipment, the time series of solid volume fraction by a fiber-optic particle concentration measuring system, the velocities of the gas and the particles by a phase Doppler anemometer.The obtained results are summarized as follows.(1) In the case with particle size distribution, the present numerical simulation gives the larger clusters compared with those without particle size distribution. In addition, the particle size distribution reduces the fluctuation of the local solid volume fraction.(2) The measurement of the corresponding experiment demonstrated that the present numerical model with particle size distribution gives the better prediction about the cluster structure than that without it.(3) In the numerical simulation, the development of the particle clusters is much suppressed by the effect of the particle size distribution. It is considered that this suppression of the cluster development is caused by the particle diffusion due to the particle-velocity fluctuation made by the size distribution.(4) The present numerical model predicts that the larger particles make the larger clusters.

为了对簇流的流动控制进行基础研究，研究了颗粒尺寸分布对簇流结构的影响。在由周期性边界包围的长方体计算域中对气固流动进行数值模拟。流体运动采用DNS计算，而固体流动则采用拉格朗日模型计算，并考虑了颗粒与颗粒的碰撞。此外，还进行了垂直管道中颗粒沉降流的实验，以测量颗粒簇的结构并验证当前的模拟。实验中，通过激光片可视化设备测量团簇的空间结构，通过光纤颗粒浓度测量系统测量固体体积分数的时间序列，通过相位多普勒风速计测量气体和颗粒的速度。得到的结果总结如下：（1）在有粒度分布的情况下，与没有粒度分布的情况相比，本数值模拟给出了更大的团簇。此外，粒度分布减小了局部固体体积分数的波动。(2)相应实验的测量表明，与没有粒度分布的数值模型相比，现有的带有粒度分布的数值模型能够更好地预测团簇结构。(3)在数值模拟中，颗粒团簇的发展受到粒度分布的影响。人们认为，这种团簇发展的抑制是由于尺寸分布造成的粒子速度波动而引起的粒子扩散造成的。(4)本数值模型预测较大的颗粒会形成较大的团簇。