| With the rapid development of oilfield lifting technology and the exploitation of highviscosity,high-sand-containing heavy oil,the progressing cavity pump is widely used as an artificial lifting equipment.The progressing cavity pump stator bushing is the core component of the progressing cavity pump to realize the medium transportation,and it is also the most important wearing part of the progressing cavity pump.When the progressing cavity pump is used in oil production projects,the poor working conditions at the bottom of the well will cause the progressing cavity pump to leak,cause serious friction and wear,which will lead to the premature failure of the progressing cavity pump.This paper takes the oil production progressing cavity pump as the research object,and uses the finite element numerical simulation method to study its sealing and tribological characteristics,in order to provide a reference for the design and engineering application of the oil production progressing cavity pump.Firstly,based on two different structures of the progressing cavity pump stator — normal stator and equal wall thickness stator,the simulation model of the stator-rotor thermal coupling of the progressing cavity pump was established to study the thermal deformation,thermal stress and frictional heat generation between the stator and rotor of the two types of stator,and the stress field of the two types of stator under pure overfill and oil pressure were compared and analyzed.The results show that compared with the normal stator,the thermal deformation of the equal wall stator is uniform and the deformation and thermal stress are smaller,and the frictional heat between the stator and the rotor is lower.The equal wall thickness stator is less affected by oil pressure,but its equivalent force is relatively large,and the outer side of the stator also generates large shear stress,which is prone to debonding phenomenon.Secondly,according to the sealing mechanism of the progressing cavity pump and the sealing performance evaluation criterion,the overall sealing condition of the two stators was obtained by using finite element simulation,and the seal failure hazard locations of the two stators were analyzed.The influence of oil pressure,overfill and temperature on the sealing performance of the two stators was studied,and the sealing performance of the two stators under different working conditions was compared and analyzed.The results show that the junction area between the linear and circular areas of the two stators is the dangerous location for seal failure.Compared with the normal stator,the contact pressure of the equal wall thickness stator is evenly distributed and the sealing effect is better.As the oil pressure increases,the sealing performance of both stators decreases,and the linear area is more affected and prone to seal failure.With the increase of the interference amount and temperature,the sealing performance of both stators is improved,and the interference amount has a significant effect.Under the same conditions,the sealing performance of equal wall thickness stator is better.Finally,the finite element simulation method was used to obtain the overall friction state of the two stators and analyze the friction stress distribution law.The simulation of the friction process of two stators with different overfill amounts and different temperatures was carried out,and the influence law of overfill amount and temperature on their friction stresses was analyzed.The results show that the frictional stresses are uniformly distributed in the stator with equal wall thickness,and the frictional stresses are higher in the linear region of the normal stator.The friction stresses of both stators increase with the increase of overfill and temperature.Under the combined influence of the two factors,it is found that the friction stress of the equal wall thickness stator is lower than that of the normal stator when the interference amount is lower than 0.3mm and the temperature is higher than 40℃. |
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