关键词: 搅拌容器, 双流体模型, 两相流, 颗粒动力学理论, 湍流

Abstract: Based on the stirred vessel with baffles and disc turbine paddle, a three dimensional Euler–Euler simulation combined with kinetic theory of granular flow (KTGF) was carried out to explore effects of structure and impeller speed on flow behavior of particles. Furthermore, the simulated solid volume fraction was compared with the experimental solid volume fraction to verify the validity. Contour plots of particle temperature and turbulent kinetic energy on horizontal cross-section were obtained to comprehend the effects of flow patterns and hydrodynamic on solid phase concentration distribution. The results showed that the particle temperature distribution at the bottom of the stirrer vessel was consistent with the solid phase concentration distribution. Based on the kinetic theory of granular flow, the influence of the baffle obstruction and the impeller speed on the solid phase concentration distribution can be reasonably explained. As the impeller speed grew up, the two-phase turbulent motion in the vessel enhanced, the particle temperature, turbulent kinetic energy and axial velocity increased, and the particle distribution became more uniform, but the particle temperature tended to be stable after reaching the complete suspension state. The accumulation of particles at the bottom of the vessel and the baffle led to an increase in local solid volume fraction and a decrease in the average free path of the particles, which in turn reduced the particle temperature. Moreover, the baffles formed a two-loop flow pattern in the vessel, which enhanced the turbulence of the fluid. But it caused accumulation of particles at the baffle, which was not conducive to the uniform distribution of the solid phase at the baffle.

Key words: stirred vessel, two-fluid model, two-phase flow, kinetic theory of granular flow, turbulent flow