The Research On Liquid-Solid Two-Phase Flow And Impeller Wear Characteristics In The Slurry-Mixing Tank

The Mixing of the liquid-solid two-phase flow has a low stirred efficiency and a large stirred power consumption in a stirred tank.The effect of the erosion and wear of the solid particles on the mixing impeller results in the degradation of the mixing performance and vibration of the mixing equipment and series of problems.Because Liquid-solid two-phase flow is extremely complex, and the theoretical analysis and experimental research methods are difficult to analyze the microscopic characteristics of the mixing.Therefore, the method of the computational fluid dynamics (CFD) is used to research the flow field characteristics of the stirred tank,which has a great significance in the hydraulic design and structural optimization of the slurry stirred tank.The mainly contents of the paper is as follows:(1)Simulation model of the stirred tank is established as follows: Pro/E is used to build geometric modeling, gambit is used to build a stirred tank grid model with unstructured grid technology and define the mesh boundary type and the type of fluid region. CFD numerical simulation methods uses multiple reference frame (MRF), the Eulerian multiphase flow model and RNG k-ε turbulence model for solving liquid-solid two-phase flow characteristics in stirred tank.(2)The slurrying performance is analyzed from the macroscopic properties and turbulence characteristics in the stirred tank.In order to improve the efficiency of the slurry, the installing angle of the mixing impeller is designed optimally. On the basis of the optimized propeller, the flow characteristics are analyzed through velocity distribution, particle concentration distribution and turbulence intensity distribution in the stirred tank to obtain the relationship between mixing performance and operating conditions. Further, under the different paddle types, the numerical simulation analyzes operating conditions on the impact of the mixing power and verify the deduced power of relational rationality.(3)Based on the liquid-solid two-phase flow, the numerical simulation analyzes particle velocity distribution, the absolute pressure distribution,shear stress distribution and the trend of the mixing impeller wear in the stirred tank of the double-layer CBY-impeller under the different operating conditions.(4) Experiments study of the fluid velocity of the axial and radial distribution and particle concentration distribution, as well as the relationship between mixing Power and rotational speed under the different concentrations in the slurrying mixing tank,then predict the mixing power number of different concentrations. the simulation results and experimental data are compared to verify the validity of the numerical simulation analysis.