Investigation On Friction Properties And Surface Texture Optimization Of Pumpjack Plunger

Petroleum is an indispensable pillar of national economic development.At present,mechanical oil extraction is the main method of petroleum exploitation,and rod pumping pump is the main method of mechanical oil extraction.As the core part of sucker rod pump,the plunger plays a key role in the service life and working efficiency of the pump.The surface wear caused by friction is the main reason for the failure of the plunger of the oil pump.At the same time,the working environment of the oil pump becomes harsh and the sand content and water content in the crude oil increase with the entering of the later stage of production,which will accelerate the shortening of the service life of the oil pump plunger,reduce the pump efficiency and restrict the oil well output.Therefore,how to design and optimize the plunger surface of oil pump and improve its friction performance has become a key problem to be solved urgently.The bionic non-smooth theory provides a new design idea for reducing drag and abrasion of the plunger of oil pump.Surface texture,as a form of bionic non-smooth design,has been widely applied to the surface of mechanical parts.Based on this,the text focuses on the optimization of the surface texture and friction characteristics of the plunger of the pump.Firstly,the drag reduction mechanism and optimization methods of surface texture are summarized,and an optimization model is proposed.According to the movement characteristics of the plunger and the pump barrel,the motion pair was simplified,the threedimensional geometric model was established,and the friction sample was designed,which laid a foundation for the following surface texture size optimization and friction test.Secondly,in order to meet the actual machining requirements of test samples and plunger,this paper designs a laser device that can process plane and rotary plane textures.According to the actual processing needs,the laser system,mechanism system and control system have been designed successively.Through the control of the marking card,the signal transmission among the light,machine and electricity can be realized to meet the final processing needs of the sample.Then,the influence of laser processing technology and processing path on the design size of the sample was investigated.Then,based on the orthogonal experiment optimization method to bionic hexagon structure parameters(element spacing,diagonal length,Angle and the ratio of transverse and longitudinal)as test factors,the friction factor as a measure,design for two different direction of friction test,and extreme difference analysis hexagon structure parameters on the main factors affecting the friction factor,further design of the main factors regression test analysis of the influence of friction factor,then according to the test result is based on bionic hexagon structure parameters and the regression equation of the relationship between friction factor.It can be seen from the three-dimensional surface obtained by the regression equation that there is an obvious interaction between the included angle and angle of the hexagon and the transverse to longitudinal ratio of the friction factor.The optimized hexagon texture in transverse and longitudinal ratio of 2,when the angle is 105° has good drag reduction effect.Finally,finite element simulation was carried out on the specimens in regression analysis with simulation software to study the distribution of the surface equivalent stress of the specimens with different textures.Then,the equivalent stress of the bionic hexagon specimen was compared with the smooth specimen to further reveal the drag reduction and wear resistance mechanism of the bionic hexagon texture.