Numerical Simulation Analysis And Optimization Design Of External Meshing Gear Pump Based On Fluent

As one of the power sources of the hydraulic system,the gear pump occupies a pivotal position in the electro-hydraulic system,which has the advantages of simple structure,low price,small volume and light quality,and has been widely used in the fields of engineering machinery and aerospace.However,with the hydraulic system to high-speed,high-pressure direction,due to its own structure and other factors caused by the flow pulsation phenomenon is also more prominent,which limits the gear pump in the direction of high-speed high-pressure applications.Therefore,the research on the cause of the flow pulsation of the gear pump has important engineering value and practical significance for the development of the gear pump with low noise and high performance.In this paper,a certain type of gear pump as the research object,to improve the accuracy of the mathematical model of the flow pulsation of the gear pump,the high precision of the simulation model and the authenticity of the internal flow state of the gear pump,the paper analyzes the flow characteristics of the different structure parameters,environment parameters and working condition parameters,and optimizes the structure parameters.The mechanism of fluid noise of gear pump is explored actively and meaningfully.In this paper,the following parts are carried out:(1)Firstly,the research background and purpose of this dissertation are described,and then the research situation of the domestic and foreign gear pump flow characteristics,flow pulsation formation mechanism and optimization algorithm are investigated and summarized.It also points out the problems and deficiencies in the past research process,and then determines the research content and methods of this dissertation.(2)The mathematic model of the flow pulsation of the gear pump is deduced and the internal flow state is simulated and analyzed with the actual working condition parameters.The relationship between the number of teeth,modulus,pressure angle,center distance and flow pulsation of gear pump is analyzed in detail,and the mathematical models including the above parameters are deduced.The CFD simulation of the internal flow state of a certain type of gear pump is established,the model takes into account the gas content of oil,effective volume modulus of elasticity,viscosity and other characteristic parameters,obtains the internal pressure,speed,noise and viscosity of the different parts of the gear pump,and intuitively reveals the flow state of different areas inside the gear pump,In this work,the cavitation phenomenon of the gear pump and the exact position of the maximum fluid noise are found.The theoretical basis and simulation platform are established for the analysis of the influence of the gear pump structure parameters,working condition parameters and oil properties on the flow pulsation.(3)The action mechanism of the gear pump operating parameters,structural parameters,oil property parameters and the flow pulsation of the gear pump is studied quantitatively.Based on the derivation of the mathematical model of the flow pulsation of the gear pump,the paper first establishes the gear pump and CFD simulation model with different structure models,and on this basis,studies the mechanism of the flow pulsation and the pressure angle,the number of teeth,the coincidence coefficient and the center distance.Then the influence of the speed and load parameters of the system on the flow pulsation is analyzed.The influence law of flow fluctuation and working condition parameters is obtained,finally,the effect of the effective volume modulus and oil viscosity parameters on the flow pulsation of the gear pump is analyzed,and a meaningful exploration is made for the forming law of the fluid noise of the gear pump.Based on the above research,considering the relationship between the efficiency,pulsation and noise of the gear pump,the reasonable working range of the gear pump is given,which provides an important reference for improving the working reliability and life of the gear pump,and provides a theoretical basis for the mechanism optimization of the gear pump.(4)A genetic algorithm is proposed to optimize the design parameters of the gear pump.Firstly,the performance constraints and geometric constraints that should be satisfied in the design process of gear pump are analyzed.Then taking the minimum instantaneous flow of the gear pump as the objective function,using the MATLAB Genetic algorithm toolbox,the optimal parameters of a gear pump are obtained,and the correctness of the conclusion is validated by establishing a CFD model of the gear pump before and after optimization.It provides a simple and efficient method for optimal design of gear pump.