英文翻译：As a kind of general fluid machinery, centrifugal pump is widely used in daily life and industrial production. It can reduce the pressure of energy demand when the efficiency of centrifugal pumps increase. In this thesis, several centrifugal pumps were studied to predict the performances and distributions of the internal flow field by using CFD method. In order to meet the practical needs, for example, to reduce the head of centrifugal pumps, a kind of centrifugal pump impeller cutting method was used in industrial practice. It can achieve the purpose of matching the specific application needs without changing a new pump. Several cut impellers were studied in this paper. The whole thesis consists of 6 chapters as follows:
The background and significance of the research is presented. The different kinds of centrifugal pumps and the application of them are introduced. The common methods of study and optimization are also discussed in this part. Then the main research contents are summarized.
The basic conception of grid is illustrated, including the software of grid generation named Gridgen and a file format named PLOT3D. The most important thing is the method of structure grid generation in a centrifugal pump. According to the different parts of the centrifugal pump, all the structure grids are accomplished including impeller part, volute part and the leakage part of the centrifugal pump by using a method of combining Gridgen with Fortran.
The process of CFD is introduced firstly. That is pre-processing, solver and post-processing. Then some commonly used turbulence models are introduced. SST and k turbulence model simulation results are compared, including the different commercial softwares of FLUENT and Ansys CFX. The last, the performances of different centrifugal pumps are studied.
The typical centrifugal pump is studied, including the distribution situations of velocity fields and pressure fields. And then, the numerical simulation results are analyzed in different conditions which include considering the leakage and different inlets.
A common method of cutting centrifugal pump impeller is introduced firstly. And then a kind of centrifugal pump impeller cutting method was put forward. That is the blades are cut only and ignored the impeller cover plates to reduce the head and increase the efficiency of centrifugal pumps based CFD numerical simulation. This method has a great practical significance to improve the performance of centrifugal pumps.
The thesis is summarized and the conclusion remarks are presented.