Structure Design And Optimization Of Electronic Water Pump For Automobile Cooling

In the automotive cooling system,the cooling water pump as the core component,its performance has an important impact on the fuel economy of the engine.Because the traditional mechanical water pump can not automatically adjust the speed,it can not meet the vehicle in different driving conditions to provide appropriate coolant,which not only causes a waste of resources,but also affects the engine fuel economy.With the development of automotive electronic technology,electronic water pump has been gradually applied to the automobile,and the related theories of electronic water pump have been enriched,which lays a foundation for the design and analysis of electronic cooling water pump in this paper.This paper studies DC motor design,pump design,pump simulation and optimization,focusing on how to improve the performance of electronic cooling water pump by optimizing the pump structure.The main work of this paper is as follows:（1）Firstly,the three-phase permanent magnet brushless DC motor is improved,which is mainly reflected in the cancellation of the motor shaft structure,and the redesign of the stator and rotor to meet the needs of pump speed and flow rate.The electromagnetic simulation software RMxprt is used to establish a two-bit motor model by parametric modeling,and the motor simulation analysis in the transient,dynamic,and under different load conditions is conducted to verify the rationality of the motor design and its performance.（2）Based on the basic theory of centrifugal pump,hydraulic model database data and similarity conversion method,the three-dimensional model of pump impeller,pump shell,isolation sleeve and other parts is established.The impeller adopts semi-open impeller design,and three flow guide blocks are added at the inlet of the pump shell to reduce the impact of cavitation and provide a physical model for subsequent flow field analysis.（3）The pressure distribution diagram,velocity vector diagram and turbulent kinetic energy distribution diagram of the surface and internal flow field of the pump impeller were obtained by numerical simulation in STARCCM+before fluid simulation.Through analysis and treatment,under the rated design speed of 3000r/min and flow rate of 90L/min,the pump head is 4.2m,4m beyond the design head,and the shaft power is 0.196 kw and the efficiency is 31.5%.The results show that the fluid simulation analysis results are consistent with the theory,and the preliminary design of the pump is reasonable,which lays the foundation for the next optimization.（4）Taking the total energy loss of the pump as the objective function,the mathematical model of pump impeller optimization was established based on the MATLAB genetic algorithm toolbox.The six main structural parameters of the cooling pump impeller were optimized:width of inlet and outlet b₁、b₂,diameter of inlet and outlet D₁、D₂ and Angle of inlet and outlet β₁、β₂.The optimization results show that the overall performance of the pump is improved after optimization,and the pump efficiency is increased by 2.3%after optimization.The head and shaft power change well,which indicates that the MATLAB genetic algorithm toolbox has a strong practical value.To sum up,the electronic water pump designed in this paper has strong practicability,simple structure,safe and reliable performance,and higher popularity,which is helpful to further improve the overall performance of the automobile engine.