Numerical modeling on friction and wear behaviors of all-metal progressive cavity pump

Abstract

The wear of the all-metal progressive cavity pump (AMPCP) has become one of the main concerns from various field applications of oil production. This work systematically reveals the mechanisms of the wear and lubrication between the stator and the rotor components of the AMPCP when lifting fluids. An efficient simulation strategy is proposed to couple the two simultaneous processes, including the rotor's dynamic behavior and material loss due to wearing. On this basis, a three-dimensional finite element model based on the explicit dynamic method is established to capture the rotation process of the rotor considering the pressure load of the inner fluid. In addition, the frictional contact and wear behavior between stator and rotor is described as well. In this regard, the wear estimation model based on the Archard wear theory is developed to depict the material loss with a geometry update and local remeshing technique, the reliability of which is well verified against experimental results. Based on the statistical results of characteristic contact time (CCT) and characteristic wear band (CWB), the wear pattern is summarized into three distinctive bands denoted by CWB I, CWB II, and CWB III, which occurs at different stages during the operating cycles of AMPCP. In particular, the influence of operational parameters (e.g., rotation speed, clearance, and lubrication) on the wear behavior and its underlying mechanisms are quantitatively revealed and discussed. The results demonstrate that the lubrication effect could substantially reduce the wear degree to extend the service life of AMPCP.