Simulation Study On Torsional Dynamics Of Sucker Rod Of Ground Driven Screw Pump

There are three main types of vibrations of the screw pump sucker rod column when working underground: lateral vibration,longitudinal vibration and torsional vibration.Among them,the torsional vibration problem is an important factor that causes the broken column and tripping of the pole.Therefore,studying the torsional vibration of the pumping rod of the screw pump can prolong the service life of the column and reduce the cost of oil production.It has important theoretical significance and practical application value.This paper mainly carried out the following aspects of research(1)In this paper,by analyzing the main performance parameters of the screw pump well and the calculation method of the axial and torsional load of the screw pump sucker rod column during normal operation,the mechanical analysis model of the pole is established.Based on the theory of vibration mechanics,the differential equation of torsional vibration of sucker rod is established.Combined with the boundary condition of torsional vibration of sucker rod column,the solution method of natural frequency and vibration mode of rod column is given.And the response model of the forced vibration of the pole is established.(2)Establishment of finite element model of rod-column torsional vibration using finite element analysis software,and modal analysis of the model.Find the natural frequency value of the member.It is compared with the theoretically calculated natural frequency values in the previous chapter to analyze the error.(3)Analyze the motion characteristics of the starting part of the rod and the load condition,and establish the torque and mechanics model of the rod starting torque.Through the analysis of the model,it can be known that the vibration of the rod is different at different starting times,and the longer the starting time is.The smoother the torque fluctuation of the rod,the smaller the torque amplitude.Therefore,in the case of working conditions,by prolonging the starting time,accidents such as breakage of the pole can be significantly avoided.(4)Analyze the reason for the reverse rotation of the rod and the common measures for the anti-reverse of the rod.The kinematics model of the energy consumption braking of the pole is established,and the model is solved and simulated.The results show that the size of the braking resistor determines the peak value of the braking torque and determines the length of the braking time.The larger the braking resistance,the larger the braking torque peak,the shorter the braking time,and the faster the rod stops.The results provide a theoretical basis for the selection of the brake resistance of the rod.