The Research On Numerical Simulation For Analysis Of Liquid-solid Two-phase Flow In The Centrifugal Impeller

Centrifugal impeller machinery whose working medium is liquid-solid two- phase fluid is widely used in many industries, as water conservancy, mine, electric power and so on. With the development of science, technology and economy, the performance of Centrifugal impeller machinery will be required to improve, while, traditional design method is not enough to accommodate the step of society development, so it is necessary to adopt modern design theories and methods, in order to improve the integrated performance of Centrifugal impeller machinery. As a new method, CFD numerical simulation can help to know fully the internal fluid characteristic of fluid machinery, so it is greatly functionary to update the design theories and methods and shorten the design period.Based on computational fluid dynamics and liquid-solid two-phase flow theories, the thesis does mainly research for the internal fluid characteristic of the centrifugal impeller of liquid-solid two-phase pump. Firstly, the physical model and the tetrahedral grids system for flow calculating have been established by using AutoCAD and Gambit software; secondly, taking respectively water and liquid-solid two-phase fluid as the medium, Fluent software has been used to calculate the internal flow field of the impeller, according to the calculation, the author has analyzed the influence of different grids and multiphase flow models on the calculation processes and results; finally, the internal flow field of the impeller has been numerically simulated in three-dimension, steady, incompressible turbulent flow by choosing Eulerian multi-phase model, standard k-epsilon model, dispersed turbulence model, and SIMPLE algorithm, the main flow characteristic has been obtained, based on the results, the author has analyzed the flow laws of some fluid parameters in the impeller in detail, including pressure, velocity, and solid phase volume fraction, and according to the computational results, the advice of improving and optimizing about the impeller have been advanced.The thesis has studied the numerical simulation of liquid-solid two-phase turbulent flow field in the centrifugal impeller. These researches are very helpful to know fully the internal two-phase flow laws of the impeller, to find distinctly the faults of the original design about the impeller, to summarize expediently the influence of the main parameters on the integrated performance of pumps, and they can offer the theoretical bases to propose the ideas about optimizing the impeller. All of these are theoretical significant and applied valuable to research more deeply the internal liquid-solid two-phase flow laws of pumps and to enhance the life and the efficiency of liquid-solid two-phase flow pumps.