A numerical study on the deformation of even thickness PCP's stator

This study focuses on analyzing the deformation characteristics of the elastomer in an even thickness PCP under several simulated working conditions. A three dimensional finite element model involving one pitch length of stator is established to simulate the deformation of the elastomer. It is known that a proper magnitude of interference of the contact pair between rotor and stator is necessary to ensure a proper contact status. An oversize of interference will induce too severe strain as well as too much resistance of torque moment. Nevertheless a deficient interference can not meet the requirement to form the suitable sealed line. Normally an elaborate uniform interference over all contact pair is designed to expect a satisfied contact interaction. However, not only the magnitude of interference is changed because of several factors, such as cavity pressure, thickness of sleeve, dissolution expansion of elastomer, deformation due to temperature change, etc., but also the interference may become unbalanced over the whole contact pair. In this paper cavity pressure coupled with Polsson's ratio of elastomer is firstly considered to investigate the deformation rule of elastomer sleeve. After that a rotor rotating in a stator is simulated to predict the characteristic of torque moment and the stress and strain of elastomer sleeve. Copyright 2010, Society of Petroleum Engineers.