静压、压差与泊松比对定子衬套变形的影响

INFLUENCE OF STATIC PRESS,PRESSURE DIFFERENCE AND POISSON'S RATIO ON DEFORMATION OF STATOR LINING

静压、压差及橡胶泊松比对螺杆钻具的输出性能和机械效率有至关重要的影响。以用量最多的5/6头螺杆钻具的定子衬套为研究对象,利用有限元软件,分析了静压及静压与压差同时作用时定子衬套的受力状态、变形规律以及橡胶泊松比对衬套变形规律的影响。结果表明,静压的改变不影响变形规律,但对变形幅值影响很大,会影响密封性能;压差作用会引起衬套变形规律与变形幅值的变化,随内压增加,压差对衬套变形的影响有所减小;橡胶泊松比的微小变化即会对定子衬套变形规律产生非常大的影响,因此,应严控橡胶质量,尽量增大定子橡胶的泊松比。研究结论可用于指导衬套过盈量的选取及线型的优化设计,以提高螺杆钻具工作效率。

Static pressure,differential pressure and Poisson's ratio of the rubber affect downhole motors' output performance and mechanical efficiency greatly.This paper takes a 5/6-lobe downhole motor which is consumed the most as research object,and the forced state and deformation regularity of a downhole motor stator lining has been obtained by FEM analysis software firstly under an static pressure and then under an static pressure with a working pressure difference.Furthermore,the affection by Poisson's ratio of the rubber is analyzed.The result shows that the deformation regularity is affected little by static pressure,but the deformation amplitude is affected more,and seriously affects the sealability;a working pressure difference can transform deformation regularity and deformation amplitude,but the influential action will be decreased as the inner pressure increased;a small change of Poisson's ratio of the rubber can affect the deformation regularity seriously.Therefore,the rubber quality should be controlled strictly and Poisson's ratio of stator rubber shuould be raised as much as possible.The research results can be applied to guide the selection of interference and optimize the design of linetype,so as to improve downhole motors' working efficiency.