Strength Analysis And Structure Optimization Of The Power End Of Multi-Opposed Plunger Pump

The multi-opposed plunger pump is a new type of water injection pump with high pressure,large flow,high efficiency and energy saving.The power end of the pump adopts a unique connection mode,in which a number of hydraulic cylinders can achieve large flow.At the same time,the bilateral symmetrical arrangement of the hydraulic cylinders makes the crankshaft force uniform,so the multi-opposed plunger pump has become the core equipment of oilfield water injection.Due to its novel and complex construction,there is still a lack of research on the performance of key components at the power end of multi-opposed plunger pumps.Aiming at the above problems,this paper takes the key parts at the power end of the 7DW200/18 opposed motorized reciprocating pump as the research object,analyzes the structural strength of the crankshaft,connecting rod and crosshead of the power end,and further optimize the structure of crankshaft support.The main work in this paper is as follows:(1)Principle analysis and establishment of analytical model for multi-opposed plunger pumps.The power end of the 7DW200/18 opposed motorized reciprocating pump is analyzed in terms of both basic structure and working principle,and a mathematical model of the singlerow opposed unit is established.From a dynamic perspective,the working load on the power end is analyzed and equivalent,and then a motion and force model of the single-row opposed unit are established.At the same time,the flow pulsation is analyzed according to the motion characteristics,laying a foundation for the strength analysis of the power end of the multiopposed plunger pump.(2)Optimization of the crankshaft supporting structure.The dynamic analysis of the crankshaft with different supporting structures is carried out,and the load variation law of the crankshaft within the whole cycle is deduced.The bending moment and internal force of the crankshaft rotation center section under different support structures are solved by using MATLAB programming.At the same time,taking the layout of the crankshaft supporting structure as the independent variable and minimizing the maximum value of the bending moment on the dangerous section as the optimization objective,the optimal supporting structure is further obtained.(3)Strength analysis of key components at the power end.Solidworks was used to establish3 D models of crankshaft,connecting rod and cross head of power end,and imported into Workbench for finite element analysis.The maximum equivalent stress and maximum deformation of crankshaft,connecting rod and crosshead are obtained by calculation under dangerous working conditions,and the strength and stiffness of the dangerous section are checked.(4)Dynamic characteristics analysis of the power end.Based on Workbench software,the modal analysis of the crankshaft with different supporting structures of 7DW200/18 opposed motorized reciprocating pump is carried out,mainly calculating the resonance frequencies and vibration modes under free and constrained states,and then analyzing the impact of resonance frequencies on the components.The power end of the fully supported structure is analyzed by using the dynamics module,and then the stress and strain of the crankshaft with time are obtained.This paper solves the problem of the lack of strength analysis at the power end of the multiopposed plunger pump based on the above research.By combining theoretical research with simulation analysis,the crankshaft supporting structure of the multi-opposed plunger pump is analyzed.The research results can provide a theoretical basis for strength analysis and support optimization of the power end.