Motion Simulation And Structure Parameter Optimization Of Epicycloid Type PCP

Because of simple construction, easy management and good adaptability, the PCP oil production system has been paid more and more attention by domestic and foreign oil filed.With the development of the three oil production technology, the PCP oil production system has become one of the most important artificial lift methods in oil field. At present, the hypocycloid type PCP which screw is made of metal and bushing is made of rubber is widely used in oil field. Because the bushing is made of rubber, the oil pipe and the sucker rod are needed to be taken out when respecting the pump to replace the bushing. The long time and high cost of pump inspection is extremely inconsistent with the long-term policy of ’high level,high benefit’. Epicycloid type line can also be used for the design of PCP in theory, but there is little research on this aspect.This paper starts with the form of epicycloid type bone line conjugate pair, The fixed contact point is found on the bushing bone line by analyzing the relative movement of epicycloid type progressive cavity pump screw-bushing pair, so the bushing can be made of metal and the screw an be made of rubber. The calculation formula of relative sliding velocity on convex tooth and concave tooth is derived by using the method of instantaneous center,then using MATLAB to build velocity curve. The further development is done to Solid Works and the parametric modeling program of epicycloid type PCP is built. Using Solid Works Motion carry on the simulation and then outputting the relative sliding speed discrete values of convex tooth contact point and concave tooth contact point, then comparing the simulation value with calculation curve, they can good fitting, the maximum deviation rate is only0.14203%. The relative sliding velocity maximum value of concave tooth is found in the middle of screw convex tooth contacting with the middle of bushing concave tooth, the maximum value of convex tooth is found in the middle of screw convex tooth contacting with the middle of bushing convex tooth.To select the indexes which can affect the performance of epicycloid type PCP such as flow area, amplitude coefficient, maximum comprehensive curvature,sliding velocity and then to build the objective function which is used to optimize the PCP by using the method of linear combination. Using threshold method to eliminate the influence of dimension. Using the fmincon function which is in MATLAB optimization toolbox to optimize the PCP. The global optimal solution is that the amplitude length coefficient K=0.757, the equal distance radius coefficient r0=1.4.