| Hydraulic pump is a widely used power component.There are four kinds of common hydraulic pumps.Because of its simple structure and strong anti pollution ability,external gear pump is widely used in mining equipment,lifting equipment,aerospace deep sea and other fields.In today’s high-speed information,the gear pump speed and load pressure requirements are higher and higher,so that it can be applied in a broader field.Based on the cavitation theory and CFD numerical simulation,the gear pump with known pump type is simulated by pumplinx to determine the maximum limit speed of the gear pump and solve the new problems caused by it.Through the control variable method,the factors that can affect the speed of gear pump are analyzed one by one,including the oil suction pressure,load pressure,diameter of oil suction port,viscosity temperature characteristics of oil and air content in oil.The factors that affect the limit speed of gear pump and how to improve the noise and air pollution caused by too high speed are analyzed by numerical simulation In addition,there are also some problems.Firstly,by understanding the working principle of gear pump,the definition of limit speed and the basic model of simulation calculation,the simulation calculation model,turbulence model,cavitation model and boundary conditions are determined.In order to save calculation resources and improve calculation efficiency,the grid independence is verified in this paper.The results show that when the number of grids is about 210000,the calculation results are more accurate.Secondly,the influence factors of gear pump limit speed were analyzed by pumplinx.The conclusion shows that: the limit speed of gear pump increases with the increase of oil suction pressure,but after the oil suction pressure reaches 0.758 mpa,the limit speed of pump begins to decrease after the oil suction pressure is increased again;appropriate increase of oil suction port size is conducive to improve the speed of pump,but it must meet the same conditions of pipeline flow rate When the temperature is about 313 k,the limit speed of the pump reaches the highest;reducing the air content of the pump is conducive to extending the service life of the pump and improving the limit speed of the pump.Finally,in view of the possible harm caused by the limit speed of the pump,some preventive measures are taken,and the feasibility is analyzed and verified by increasing the oil suction pressure of the pump and improving the tooth profile.The results show that increasing the suction pressure of the pump can reduce the flow pulsation of the pump,so that the pressure pulsation can be reduced,and the noise of the pump can be restrained to a certain extent;the new gear pump with teeth can effectively restrain the cavitation phenomenon in the gear pump. |
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