Research On The Wear Mechanism And Countermeasures Of The Electric Submersible Centrifugal Pump

Submersible centrifugal pump is the core component of electric submersible pump unit,and also is the most prone to break down.As the oil production come into high water-cut period,the running environment of electric submersible pump becomes severe,and the failure rate gets higher and higher,which results in huge economic losses.Submersible pump wear is mainly manifested in two aspects: the wall erosion wear and even punching fracture of the pump barrel,and the eccentric wear between the impeller and guide roller,which both have a serious impact on the efficiency and the service life of submersible pump.Research on submersible pump wear mechanisms and countermeasures,has great significance on improving the operating cycle of submersible pump.In this paper,the erosion wear of the submersible pump is analyzed by numerical simulation.First of all,this part analyzes the numerical calculation method of solid-liquid two-phase flow in centrifugal pump,and describes the characteristics of the two fluid model,discrete phase model and the process of CFD erosion calculation,which provides the theoretical basis for the simulation.Then the submersible centrifugal pump solid-liquid two-phase flow field is simulated by using the two fluid model and discrete phase model of the software Fluent.Two-fluid model is used to analyze the distribution of the flow field pressure,velocity and volume fraction of sand,and discrete phase model is used to investigate the location and degree of erosion wear.The analysis results show that: the erosion wear of the head to the middle parts of blade suction surface,and the inlet and the outlet parts of blade working surface is serious,and the sealing ring of guide roller is the most serious wear position.Finally,the effect of working parameters such as sand concentration and particle size,structural parameters such as the impeller blade inlet & outlet installation angles,on the flow field and the distribution of wear,are analyzed by using two fluid model and discrete phase model.Considering the distribution of the flow field and wear,a conclusion is gotten: the blade inlet angle should be larger,and outlet blade angle should not be too large or too small.According to the problem of eccentric wear between the impeller and guide wheel,the forms and characteristics of the eccentric wear of electric submersible pump are described,and the causes of eccentric wear are analyzed,some countermeasures are given.The structure of high efficiency impeller and the vibration are important causes of eccentric wear.The shape and degree of eccentric wear abrasion under different size relationships between offset distance and tolerance clearance,are discussed.