Transverse vibration driven by radial force of sucker rod string in screw pump production system

Key words:  screw pump  production rod string  rotation and revolution  liquid radial force  transverse vibration

Abstract:

The transverse vibration of a rod was the main cause of failure in the screw pump production system. The influence of liquid radial force on the transverse vibration law of rod was studied when the rod rotates at a uniform speed. The mathematical model of liquid radial force was obtained by the simulation fitting method, and the action law of radial force and rotational centrifugal force on the rod was studied. Then a simulation model on the transverse vibration of the column was established, in which the liquid radial force and the centrifugal force due to eccentric rotation of the column were transverse excitations, and the influence of the liquid radial force on the transverse vibration law of the column was studied. The differential vibration equation was solved by the numerical method. The results show that the direction change of the liquid radial force is related to the eccentricity and there is a critical eccentricity value to convert the direction of the radial force. When the radial force is considered, the collision force between the rod and the tube increases, the number of collisions increases, the time of the first collision between the rod and the tube is shortened, and the volatility of rod column is larger. The maximum value of the collision force appears near the bottom and the middle of the rod column. The longer the working time of the rod, the more obvious the overall vibration and the more irregular the shape.