3D flow simulation of a baffled stirred tank for an assessment of geometry simplifications and a scale-adaptive turbulence model
3D flow simulation of a baffled stirred tank for an assessment of geometry simplifications and a scale-adaptive turbulence model
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DOI：
10.1016/j.ces.2020.116262
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发表时间：
2020-11
影响因子：
4.7
通讯作者：
Kevin Rave;Martin Lehmenkühler;D. Wirz;H. Bart;R. Skoda
中科院分区：
文献类型：
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作者：
Kevin Rave;Martin Lehmenkühler;D. Wirz;H. Bart;R. Skoda
对由 Rushton 涡轮以 40 000 雷诺数搅拌的折流罐中的单相流进行流动模拟。讨论了流动物理，并强调了尺度自适应模拟 (SAS) 与经典非定常雷诺平均纳维斯托克斯 (URANS) 模型相比的优势。说明了几何简化（即无限薄叶片）的效果。此外，由于低频流动不稳定性的存在，证明了在模拟中利用完整的 360° 计算域并考虑最多 150 次叶轮转数的必要性。通过叶片和尾流区域内的分区网格细化，研究了湍流谱的连续解析部分。即使在通常用于 URANS 模拟的计算网格上，与传统的 URANS 模型相比，SAS 也显示出对平均速度和湍流统计的显着改进的预测，因此应该优先于例如解析不足的大涡模拟 (LES)。
Flow simulations are performed on single-phase flow in a baffled tank stirred by a Rushton turbine at a Reynolds number of 40 000. The flow physics are discussed, and the benefits of a scale-adaptive simulation (SAS) compared with classical unsteady Reynolds-averaged Navier-Stokes (URANS) models are highlighted. The effect of geometry simplifications, ie, infinitely thin blades, is illustrated. Furthermore, due to the existence of low-frequency flow instabilities, the necessity of utilizing a full 360° computational domain and the consideration of up to 150 impeller revolutions in the simulation is demonstrated. By a zonal grid refinement within the blade and wake region, the successively resolved portion of the turbulent spectrum is investigated. Even on computational grids typically employed for URANS simulations, the SAS shows a considerably improved prediction of mean velocity and turbulence statistics, compared with conventional URANS models, and should thus be preferred, eg, to an under-resolved large eddy simulation (LES).