Research On Transient Numerical Simulation Of Internal Flow Field In External Gear Pump

Gear pump is widely used in metallurgical machinery,aerospace,engineering machinery and other fields because it has simple and compact structure,strong ability to resist pollution,good self-priming performance,reliable operation,low cost and allow the advantages of high speed.At the same time,external gear pump has many disadvantages limited it in high precision,high pressure and demanding environment,such as flow pulsation,bigger noise,displacement cannot adjust,low volumetric efficiency of low speed work,unbalanced radial force and leakage problems.So the researchon transient numerical simulation of internal flow field in external gear pump has important for theoretical significance and practical value.Paper based on theoretical calculation and numerical simulation to analyze the internal leakage of pump and efficiency loss.The article main content has the following five aspects:In the first chapter,the research background and significance of the article was presented.Working principle of external gear pump,phenomenon of trapped oil was discussed.Unbalanced radial force,leakage of gear pump and other problems was explained.At the same time,the research of overseas and domestic status was discussed.In the second chapter,numerical simulation model and calculation equations was introduced.The adaptability of the grid was verified and the volume efficiency of gear pump under no-load condition were calculated.Finally the simulation value compared with the theoretical value,to ensure the accuracy and adaptability of the model.In the third chapter,the gear pump's leakage of tooth tip clearance was carried on the theoretical calculation.At the same time,under the condition of different pump tip clearance,the tip leakage problem?the cavity pressure distribution?the dynamic force and the torque of drive gear and slave gear were analyzed of the numerical simulation.As a result,the conclusion of numerical simulation and theoretical value was compared.In the fourth chapter,the gear pump's leakage of tooth surface clearance was presented on the theoretical calculation.Then as the gear surface clearance size,rotational speed and pressure of outlet with variables,gear pump leaks,the distribution of cavity pressure,the dynamic force and the torque of drive gear and slave gear were analyzed for the numerical simulation.As a result,the conclusion of numerical simulation and theoretical value is compared.In the fifth chapter,this chapter focuses on the volumetric efficiency loss and mechanical efficiency loss problems of gear pump in different tip clearance and surface clearance.Used the outlet pressure as variable,power,flow and volume efficiency of gear pump was carried on the numerical simulation.Lastly,the research work and achievements in this thesis were summarized and the contents perfect and the future research proposals were suggested.