浆化搅拌槽的液固两相流及叶轮磨损特性的研究

发布时间：2018-03-08 06:22

本文选题：搅拌槽　切入点：液固两相流　出处：《中南大学》2012年硕士论文　论文类型：学位论文

【摘要】：搅拌槽内液固两相流的搅拌混合效率低,能耗大并且由于固体颗粒对搅拌叶轮的冲蚀磨损作用导致搅拌性能下降、振动等一系列问题。由于液固两相流流动复杂,依靠理论分析和实验研究的方法难以对搅拌混合的微观特性进行分析。因此,采用计算流体力学(CFD)的方法研究搅拌槽的流场特性,对浆化搅拌槽水力设计和结构优化有重要意义。论文的主要研究内容： (1)搅拌槽仿真模型的建立。综合运用Pro/E几何造型技术、Gambit构建搅拌槽的非结构化网格模型,并定义网格模型的边界类型和流体区域类型。采用CFD数值模拟的方法,应用多重参考系法(MRF)、 Eulerian多相流模型、RNG k-e湍流模型求解搅拌槽液固两相流流场特性。 (2)从宏观特性和湍流特性两方面数值模拟不同桨型的搅拌槽的浆化性能,以提高浆化效率为目标对搅拌叶轮安装角进行优化设计。在优化桨型的基础上,分析了搅拌槽在不同工况时的流场速度分布、颗粒浓度分布、湍流强度分布进而分析搅拌工况对搅拌性能的影响,并分析了不同桨型在不同工艺参数时对搅拌功率的影响,并验证了推导的功率关联式的合理性。 (3)基于液固两相流分析了双层CBY搅拌桨的搅拌槽在不同的工况下粘性颗粒的速度分布、绝对压力分布、剪应力分布并由此分析了搅拌叶轮的磨损趋势。 (4)通过实验研究浆化搅拌槽轴向和径向的速度分布和颗粒浓度分布,以及不同浓度下搅拌功率与转速的关系,并预测了不同浓度的搅拌功率准数,将模拟结果与实验数据进行了对比,验证数值模拟分析的有效性。
[Abstract]:The mixing efficiency of liquid-solid two-phase flow in the stirred tank is low, the energy consumption is high, and a series of problems such as the deterioration of stirring performance and vibration caused by the erosion and wear of solid particles on the impeller are also discussed. It is difficult to analyze the microscopic characteristics of mixing by means of theoretical analysis and experimental study. Therefore, the flow field characteristics of stirred tank are studied by the method of computational fluid dynamics (CFD). It is of great significance to the hydraulic design and structure optimization of slurry agitator. The main contents of this paper are as follows:. 1) Establishment of agitator simulation model. The unstructured mesh model of agitator is constructed by using Pro/E geometric modeling technique, and the boundary type and fluid region type of the grid model are defined. The method of CFD numerical simulation is used. The multi-reference system method and Eulerian multiphase flow model are used to solve the characteristics of liquid-solid two-phase flow field in stirred tank. (2) the slurry performance of different impeller is simulated from macroscopic characteristic and turbulence characteristic, and the optimum design of impeller installation angle is carried out with the aim of improving slurry efficiency. On the basis of optimization of impeller type, The flow field velocity distribution, particle concentration distribution, turbulence intensity distribution of the stirred tank under different conditions are analyzed, and the influence of stirring conditions on the mixing performance is analyzed, and the influence of different propeller types on the stirring power under different technological parameters is analyzed. The rationality of the derived power correlation is verified. Based on the liquid-solid two-phase flow, the velocity distribution, absolute pressure distribution and shear stress distribution of viscous particles in the stirred tank of double-layer CBY impeller under different working conditions are analyzed, and the wear tendency of the impeller is analyzed. (4) the velocity distribution and particle concentration distribution in axial and radial direction of slurry mixing tank and the relationship between stirring power and rotating speed at different concentration were studied experimentally, and the number of mixing power criterion of different concentration was predicted. The simulation results are compared with the experimental data to verify the validity of the numerical simulation analysis.
【学位授予单位】：中南大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：TH117;O359

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