Flow filed characteristics of new-type multi-impeller submersible mixer
TIAN Fei1,2, SHI Weidong3*, ZHANG Desheng4, CAO Weidong4, ZHOU Qin2
1. School of Energy and Power Engineering, Jiangsu University, Zhenjiang, Jiangsu 212013, China; 2. Yatai Pump &Valve Co. Ltd., Taixing, Jiangsu 225400, China; 3. School of Mechanical Enginee-ring, Nantong University, Nantong, Jiangsu 226019, China; 4. National Research Center of Pumps, Jiangsu University, Zhenjiang, Jiangsu 212013, China
To improve the mixing effect of a submersible mixer, a series of new-type multi-impeller mixers were designed for sewage treatment pools in various shapes. Based on CFD software ANSYS Fluent 15.0, the flow field of two new-type multi-impeller submersible mixers was studied in this paper. The results show that the effective axial propulsion distances in the new-type two-way submersible mixer and the new-type two-impeller submersible mixer are 2 times and 1.8 times that of the traditional mixer, and the average velocities of the fluid in the pool are 0.194 m/s and 0.215 m/s, respectively, which are close to the average velocity of 0.203 m/s in the traditional mixer. The maximum velocity curve induced by the new two-way submersible mixer is saddle-shaped, and the velocity difference is greater, only 73.2% of the fluid in the pool is with a velocity higher than 0.050 m/s, and the low-velocity zone is in the middle and upper part of the pool. The maximum velocity curve generated by the new-type two-impeller submersible mixer is in a hyperbolic decreasing shape. 78.71% of the fluid in the pool is in a velocity between 0.100 and 0.300 m/s, and the low-velocity zone accounts for 1.55% of the water body in the pool. Thus, two new-type mixers designed are obviously better than the traditional mixer in performance. The results can provide a reference for practical engineering application of submersible mixers.
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