Study On Lifting Performance Of Epicycloid Type PCP

Screw pump production is one of the main methods of oil field production.At present,Daqing oilfield has entered the three stage of oil production,which puts forward higher requirements for the lift performance and life of the screw pump.Widely used in oil field production is an internal spiral pump,and most of the theoretical research is also for the internal pendulum type.Internal cycloid screw pump has short service life,high cost of replacement pump,external cycloidal screw pump rotor is vulnerable,it will greatly reduce the cost of operation,this paper starts to study the lifting performance of external cycloidal screw pump from the linear change of screw pump,which lays the theoretical foundation for the outer cycloid screw pump applied to oil production.According to the bone line of epicycloid rotor equation,obtain rotor bone line coordinates by using Matlab software,draw a line type bone line and equidistant access point method in SolidWorks,and the different structure parameters of swing type screw pump geometry model.According to the actual working condition of screw pump,the experimental data and the five constitutive models were fitted using the Ogden model as the rotor outer lining rubber constitutive model and the model parameters are determined,then choosing element type,mesh,contact of the establishment and the setting of boundary conditions,established 1/3 lead(contains two complete chamber)the finite element analysis model.Using ANSYS software to simulate the calculation of contact pressure on the sealing strip,sealing screw pump according to the failure criterion,determine the weak position in the middle of the long spiral seal belt,in this region as the research object,research on sealing and leakage between the screw pump chamber.The pressure and pressure difference between the chambers of the finite element model are simulated to simulate the working conditions of the finite chamber of the screw pump,and the critical contact pressure between the adjacent chambers of the screw pump is calculated respectively.Using Matlab software,the curve of critical contact pressure with pressure in low pressure chamber is fitted by finite data points.Then the pressure field distribution and the lift pressure of screw pump are calculated according to the pressure transfer law in each chamber of the screw pump.The influence of eccentricity,lead and interference on lift pressure of cycloidal screw pump is studied by using the method of control variables,and the reasonable range of eccentricity,lead and interference is obtained.Considering the friction stress,the equivalent stress and the displacement,the optimum selection principle of various kinds of screw pumps for oil wells is given,and the structural parameters of the cycloidal single screw pump are optimized by taking large displacement and deep well as an example.