Research On Dynamic Characteristics Of Oil Extraction Progressing Cavity Pump Rotor Based On Rubber Nonlinearity

Oil extraction progressing cavity pump is widely used in the oil field because of its unique advantages,such as small consumption,high efficiency,easy installation and other advantages of outstanding performance.However,the vibration of the oil extraction progressing cavity pump is large at high speed,and it is difficult to meet the requirements of stability.Considering this practical need,this paper analyzes the friction characteristics of the rotor system of the single screw pump from the perspective of friction dynamics.According to the movement characteristics of the rotor of oil extraction progressing cavity pump,the single period movement of the rotor in the stator cavity is divided into the curve movement interval and the linear movement interval.The stress state of the rotor in the two movement intervals is analyzed.Considering the influence of the thickness change of stator rubber and the nonlinear factors of rubber itself,the stress state of rotor in different positions of stator cavity was analyzed by using the finite element method and ABAQUS software,and the formula of the contact force of stator rubber was deduced.According to the rotor dynamics theory,combined with the conventional rotor system modeling method,the rotor of the screw pump was equivalent to the cross section,and the friction dynamics model of the rotor system of the oil extraction progressing cavity pump was established.Using the finite element method,ABAQUS software was used to solve the friction dynamics model of the oil extraction progressing cavity pump system,and the dynamics simulation results were analyzed by combining the rotor centroid amplitude diagram.The contact pressure variation between rotor and stator was analyzed when the rotor was running in the stator cavity.Taking rotor speed as variable factor,the influence of rotor rotation speed on the response characteristics of the rotor rubbing system of progressing cavity pump,and the relationship between the stable speed of each system and the amount of interference under different situations were analyzed.Besides the influence of amount of interference on the response characteristics was obtained.The results show that the motion of the rotor centroid is regular at a fixed speed within a certain speed range.In the amplitude history diagram of the rotor,the maximum vibration displacement increases with the increase of rotational speed.At the same time,the optimal stable speed range of the rotor system is obtained.Under the condition of different amount of interference,the rotational speed is the stable rotational speed of the rotor system,and the relationship between the stable amplitude of the rotor and amount of interference is obtained.