穿流-刚柔组合桨强化固液两相的悬浮行为

Solid-liquid suspension behavior intensified by punched rigid-flexible impeller

采用双向流固耦合计算方法对搅拌槽内刚性桨(RDT-PBDT)、刚性组合桨(R-RDT-PBDT)、刚柔组合桨(RF-RDT-PBDT)、穿流-刚性组合桨(PR-RDT-PBDT)以及穿流-刚柔组合桨(PRF-RDT-PBDT)体系中的固液两相悬浮特性和桨叶总变形量、等效应力进行了研究。结果表明,在相同功耗下,PRF-RDT-PBDT的最大变形量分别是RDT-PBDT、R-RDT-PBDT、RF-RDT-PBDT、PR-RDT-PBDT的1.984×106倍、1.247×103倍、1.169倍、1.041×103倍。PRF-RDT-PBDT的应力大于RDT-PBDT、R-RDT-PBDT、RF-RDT-PBDT的,比PR-RDT-PBDT的应力分布更均匀。PRF-RDT-PBDT体系的固体颗粒最大Uz/Utip值和最大ε/D2N 3值分别比RDT-PBDT、R-RDT-PBDT、RF-RDT-PBDT和PR-RDT-PBDT体系提高了53.08%和80.84%,38.03%和28.42%,22.14%和20.16%,10.85%和5.725%。PRF-RDT-PBDT能够增大与流体之间的相互耦合作用,增大固体颗粒的轴向速度,提高体系的湍动能耗散率,减小搅拌槽底部固体颗粒的堆积程度,提高固体颗粒的悬浮程度。

The total deformation and equivalent stress of impeller, and hydrodynamics of solid-liquid suspension process in a stirred tank with RDT-PBDT, R-RDT-PBDT, RF-RDT-PBDT, PR-RDT-PBDT and PRF-RDT-PBDT were investigated using bidirectional fluid-structure interaction（FSI） method. Results showed that, at the same power consumption, the total deformation of PRF-RDT-PBDT was 1.984×106, 1.247×103, 1.169, 1.041×103 times of RDT-PBDT, R-RDT-PBDT, RF-RDT-PBDT and PR-RDT-PBDT, respectively. The equivalent stress of PRF-RDT-PBDT was larger than that of RDT-PBDT, R-RDT-PBDT and RF-RDT-PBDT, and was more homogeneous than that of PR-RDT-PBDT. The maximum Uz/Utip value of solid particle and maximum ε/D2 N3 value in PRF-RDT-PBDT system were 53.08% and 80.84%,38.03% and 28.42%,22.14% and 20.16%,10.85% and 5.725%, which are higher compared with RDT-PBDT, R-RDT-PBDT, RF-RDT-PBDT, PR-RDT-PBDT, respectively. Therefore, PRF-RDT-PBDT can enhance mutual coupling effect with fluid, increase axial velocity of solid particles and turbulent energy dissipation rate, reduce the accumulation of solid particles at the bottom of stirring tank, and improve the solid-liquid mixing performance.