Simulation Study On The Lateral Vibration Characteristics For The Rod String Of Progressive Cavity Pump

Lateral vibration problems of the rod string is an important factor leading to partial abrasion and screw rod string broken, so the research of the lateral vibration of the progressive cavity pump rod string has important theoretical and practical significance. To solve this problem, the following aspects are discussed in this paper.First, the environment loads and their computation method were particularly researched The mechanical model for the following research was also founded.Second, the mechanics model and the mathematical model of the lateral vibration of the progressive cavity pump were gained based on the elastic theory, considering the influences of the axial force and axial distribution force on the rod string. Using the mode superposition method and taking the boundary conditions of the lateral vibration into consideration, lateral vibration equation of rod string was established. Then, the integral method was used to solve the equation to get the solution of the natural frequencies and the corresponding vibration modes of the rod string. The influence factors of the natural frequencies were analyzed and the response pattern model was gained.Third, discrete the rod string into several elements, consider the effects of the axial force and axial distribution force on the element rigid, utilize the flexibility matrix method and bulid the lateral vibration simulation model to solve the natural frequencies. The natural frequencies and the vibration modes were gained. The dynamic simulation model of the discrete system was established.Last, make use of the MATLAB and the Visual Basic 6.0 to develop the simulation software of rod string for the surface-driven progressive cavity pump. Some characteristics like natural frequencies and vibration modes can be gained by this software.