Particle-resolved direct numerical simulation of a 4-baffled cylindrical stirred tank with a 6-pitched blade-turbine-downflow (PBTD) impeller was carried out for the first time to understand the hydrodynamic characteristics of its turbulent solid-liquid flow. The fluid-particle and fluid-wall interactions are numerically described by the immersed boundary method (IBM) with smeared and sharp interfaces jointly on a staggered Cartesian grid. The particle diameter is 1 mm, and the impeller rotation speed changes between 23.88 and 15.88 rev/s, resulting in the impeller Reynolds number at 7031 and 4676, respectively, belonging to medium turbulent regime. The average solid volume fraction ranged from 0 to 0.1. The effect of particle inertia was also investigated by changing the particle-fluid density ratio from 1.5 to 3.0. Analysis of the simulation results indicates turbulence suppression in both the near-wall annular region and the core region and particle-induced strengthening of the axial liquid circulation. The quasi-steady and unsteady drag is correlated to the relative turbulence intensity and the turbulence dissipation rate obtained from the simulation data, respectively.

首次进行了带有6螺距叶片-涡轮-下降流（PBTD）叶轮的4挡板圆柱搅拌槽的颗粒解析直接数值模拟，以了解其湍流固液流动的流体动力学特性。流体-颗粒和流体-壁之间的相互作用通过沉浸边界方法（IBM）在交错的笛卡尔网格上联合使用具有模糊和尖锐界面的数值描述。粒径为1 mm，叶轮转速在23.88和15.88 rev / s之间变化，导致叶轮雷诺数分别为7031和4676，属于中等湍流状态。平均固体体积分数为0至0.1。还通过将颗粒-流体密度比从1.5更改为3.0来研究颗粒惯性的影响。对模拟结果的分析表明，在近壁环形区域和核心区域都抑制了湍流，并且颗粒诱导了轴向液体循环的增强。准稳态和非稳态阻力分别与从模拟数据获得的相对湍流强度和湍流耗散率相关。