| Centrifugal pump is an important energy conversion and fluid transfer device.Fluoroplastic is widely used in industrial,agricultural and aerospace applications for its high corrosion resistance.Developed countries such as Europe and the United States have long-term research on the performance prediction and internal flow field analysis of fluoroplastic centrifugal pumps.The theoretical basis is relatively perfect of these countries.For China,the theoretical methods and flow field analysis are far behind developed countries.Therefore,perfecting domestic theoretical basis of centrifugal pumps has far-reaching significance for the development of industry,agriculture and aerospace.The CFD method is an excellent and efficient way to optimize the performance of centrifugal pumps.In recent years,it has been widely used in performance optimization simulation of centrifugal pump.In summary,based on the large eddy simulation,the performance analysis of the fluoroplastic centrifugal pump is closely combined with the study of computational fluid dynamics.Then,the velocity,pressure and vorticity distribution of full flow field of the centrifugal pump are obtained and the performance of the flow field under each flow is analyzed,which has some help and guidance for the structural design and performance analysis of centrifugal pump.In this paper,the following detailed research is carried out:Firstly,The inner flow-path and impeller of the pump are modeled according to the wood model of blade,axial projection of twisted blade,hydraulic model of volute and sectional view of volute using CATIA.Secondly,based on the basic theory of fluid mechanics,the flow field simulation of flow-path is carried out by XFlow based on large eddy simulation(LES),and the internal flow field distribution of velocity,static pressure and vorticity is obtained.Thirdly,the data acquisition system of each parameter of the fluoroplastic centrifugal pump is built by GE PAC,and the operation process is monitored in real time through iFIX to obtain the data of each parameter.Finally,the result of numerical simulation and test were compared and analyzed,and the conclusions of the influence of different structures of impeller on performance were obtained.The flow field distribution obtained by the simulation shows in detail the influence of the number of blades on the flow field of inner flow-path.This mumerical simulation uses large eddy simulation(LES).The principle is to directly simulate the turbulent motion with large turbulence intensity through the grid.At the same time,the subgrid model is used to simulate the influence of the turbulent motion with less turbulence intensity on the turbulent motion with stronger turbulence intensity.LES can obtain many flow field microstructures and flow images that cannot be obtained by the Reynolds-averaged Navier-stokes(RANS)method.Afterwards,the "simulation-test" comparison analysis on the efficiency-flow and head-flow of the six-blade fluoroplastic centrifugal pump was carried out,which verified the rationality of the numerical simulation of flow-path of the six-blade fluoroplastic centrifugal pump,and then got the conclusion that the numerical simulation of flow-path of each blade is reasonable.The simulation results show that the excessive number of blades will increase the friction of the blade surface,which will reduce the total power at the outlet of the centrifugal pump,thus reducing the lift and efficiency of the centrifugal pump.After simulation and test analysis,it is found that when the number of blades is 5,the flow field of centrifugal pump has the best comprehensive performance,the highest operating efficiency,low turbulence intensity and best flow field stability.This paper provides some theoretical support for the analysis of the structure and performance of fluoroplastic centriftigal pump.It has more practical significance for improving the quality of centrifugal pump products,and has a guiding role in the actual production of centrifugal pump casing. |
PDF Full Text Request