Pressure Distribution Law Study Of Progressive Cavity Pump Based On 3D Modeling

The PCP has been used in oilfields at home and abroad because of simple structure, high efficiency and wide application. Now, the head of the PCP is limited that limits the application of it in deep wells and ultra deep wells. Therefore, the research of the PCP's pressure distribution law and its influencing factors has an important practical significance to raise the head. At present, most researches are made use of plane models which has a certain deviation. The PCP's pressure distribution law has been researched by the 3D models.The dynamic relationship of the PCP between sealing and leakage has been studied, which showed that the lift and leak among the chambers is a dynamic balance state when the PCP is working stably. And then, the sealing standard has been determined between the stator and the rotor. That is, the PCP is sealed when the pressure of the adjacent chamber is greater than the contact pressure; otherwise, the leak occurred.The GLB120-27 used widely in oilfields has been defined to studying object. The 3D solid model of half lead has been established by SolidWorks and ANSYS. In the modeling process, the constitutive relation of stator rubber is Mooney—Rivlin model and the original parameters have been modified. The chamber surface of the stator is separated by Boolean. The chamber surface and the sealed belts between adjacent chambers have been established contact in order to properly simulating the fluid pressure in the chambers. The location of the PCP's first leaks has been determined by the finite element calculation which is close to the semicircle in the sealed belt.Making use of the PCP's three-dimensional finite element model to change the pressure, and complete the finite element calculations. The relations between the critical contact pressure and difference pressure of the sealed location have been analyzed. And then, the contact pressure between the adjacent chambers has been determined. The critical contact pressure of the PCP's higher, middle and lower chambers is determined by this method. The critical contact pressure has been made for polynomial fitting by MATLAB. The pressure distribution of GLB120-27 has been obtained. The head is 10.77MPa. Its actual head which has been measured is 10.5MPa by the hydraulic characteristics tests. The deviation of the finite element simulation results is 2.26%, which verifies the correctness of the simulation results.This method has been used to study that the variation law of the GLB120-27's head changes with the rubber Poisson ratio, indicating that the Poisson ratio increased by 0.0003, the head increased more than 300 meters.