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
Abstract: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.
[1]田飞,施卫东,张德胜.潜水搅拌机理论、设计及工程应用[M].北京:科学出版社,2016.[2]中华人民共和国国家质量监督检验检疫总局、中国国家标准化管理委员会. CJ/T109—2007潜水搅拌机[S].北京: 中国标准出版社,2007.[3]石磊, 张德胜, 陈健, 等. 基于PANS模型的轴流泵叶顶空化特性[J]. 排灌机械工程学报, 2016, 34(7): 590-596. SHI Lei, ZHANG Desheng, CHEN Jian, et al. Analysis on characteristics of tip cavitation in an axial-flow pump based on PANS model[J]. Journal of drainage and irrigation machinery engineering, 2016, 34(7): 590-596.(in Chinese)[4]TERASHIMA M, GOEL R, KOMATSU K, et al. CFD simulation of mixing in anaerobic digesters[J]. Bioresource technology, 2009, 100(7):2228-2233.[5]TIANF, SHI W D, He X H, et al. Study on installation of the submersible mixer[C]//Proceedings of the 6th International Conference on Pumps and Fans with Compressors and Wind Turbines, 2013.[6]谭林伟, 施卫东, 张德胜, 等. 叶片出口安放角对单叶片泵性能的影响[J]. 排灌机械工程学报, 2017, 35(10): 835-841. TAN Linwei, SHI Weidong, ZHANG Desheng, et al. Effects of blade outlet angle on the performance for single blade pumps[J]. Journal of drainage and irrigation machinery engineering, 2017, 35(10): 835-841.(in Chinese)[7]TIAN Fei, SHI Weidong,JIANG Hua,et al.A study on two-phase flow of multiple submersible mixers based on rigid-lid assumption[J].Advances in mechanical engineering,2014(5):1-7.[8]YOSHIDA M, EBINA H, ISHIOKA K, et al. Hydraulic design and power characterization of closed turbine-type agitator[J]. International journal of chemical reactor engineering, 2017, 15(4):20160198.[9]SHI WD, TIAN F, LU X N, et al. Strength analysis of the submersible mixer[J]. Applied mechanics and materials, 2012, 197:18-23. [10]OCHIENG A, ONYANGO M S, KUMAR A, et al. Mixing in a tank stirred by a Rushton turbine at a low clearance[J]. Chemical engineering & processing process intensification, 2008, 47(5):842-851.