水力旋流器旋流运动的格子Boltzmann模拟

Lattice Boltzmann simulation of swirling flow in hydrocyclone

为确定格子Boltzmann方法对水力旋流器中旋流场模拟的适用性,基于水力旋流器的实验模型,采用格子Boltzmann方法,对水力旋流器内单相旋流场进行了模拟,并将本文模拟得到的平均速度分布与实验结果进行对比,给出了平均切向速度和平均轴向速度与实验值的相对误差。结果表明:格子Boltzmann方法能够模拟出水力旋流器中存在的旋流运动,并捕捉到流场的二次回流现象以及涡核的非稳态特征;模拟获得的平均轴向速度和平均切向速度分布与实验结果基本吻合,且对中心二次回流的模拟结果好于Hreiz(2011)文献模拟结果;模拟得出了平均径向速度在轴向上的方向交替变化,这与Hreiz(2011)结论吻合,并给出了水力旋流器中存在的旋进涡核现象。由此证明,格子Boltzmann方法可用于水力旋流器内旋流场的模拟。

To determine the suitability of the lattice Bohzmann method for swirling flow field in a hydrocyclone, the liquid swirling flow was numerically simulated based on the experimental model of the hydrocyclone and the lattice Boltzmann method. The distribution of the mean speed obtained by simulation in the study and the experimental re- sults were compared. Then, the relative errors between the average tangential speed, average axial speed, and exper- imental values were given. The results indicate that the lattice Bohzmann method can simulate the swirling flow and capture the secondary backflow phenomenon and unstable characteristics of the vortex core of the fluid field in the hydrocyclone. The distribution of the average tangential and axial velocity obtained by simulation are basically in a- greement with the experimental resuhs, and the simulation results on the secondary backflow in the center is better than the results by Hreiz（2011 ）. The simulation shows that the mean radial velocity alternately changes in axial di- rection, which is consistent with the conclusion by Hreiz（2011）. Meanwhile, the phenomenon of precessing the vor- tex core in the hydrocyclone was effectively predicted. Therefore, the results of this study show that the lattice Boltz- mann method can be used to simulate the swirling flow field in the hydrocyclone.