铝合金油管特殊螺纹接头设计及密封性能

以应用于油井特殊环境下的铝合金油管为研究对象,对其接头螺纹及密封进行了设计研究。首先根据应用环境,确定了接头的结构及密封形式,然后采用理论设计方法,对偏梯形螺纹进行等强度设计,通过建立二维轴对称有限元模型,对螺纹面、密封锥面、密封环的密封特性进行了设计研究,结果表明:螺纹面和锥面的接触应力都随着其自身过盈量的增加而增加,但内外锥面的接触应力随着螺纹面过盈量的增加而减少,螺纹面的接触应力随锥面的过盈量变化不大。端面密封环过盈量的设计要综合考虑油管及自身受力的变形,以确保在密封环的变形量在其弹性范围内,提供较好的密封性能。最后以设计的结构参数为例,分析了接头在不同工况下的强度及密封性能,结果满足应用要求,验证了设计的合理性。

Study on Premium Connections and Sealing Performance of Aluminum Alloy Tubing

In order to have better performance in the special environment of oil well, the premium connections and sealing performance of aluminum alloy tubing was studied. First, the structure and sealing type were determined according to the application environment. An equal strength design of partial trapezoidal thread was carried out by using the theory design method. Through the establishment of nipple two-dimensional axisymmetric finite element model, the sealing characteristics of thread surface, sealing cone surface and sealing ring were designed. The results show that the contact stress of screw thread surface and taper surface are as its own interference increases, but the contact pressure of inner and outer cone with the increment of the thread surface interference are reduced. The contact pressure of the thread surface varies little with the cone surface interference. The design of the sealing ring interference should take the deformation of tube and itself into consideration comprehensively, to ensure that the deformation amount of the sealing ring is within its elastic range and has better sealing performance. Finally, an example was given according to the designed structure, the strength and sealing performance of the thread under different working conditions were analyzed. The results meet the application requirements and verify the rationality of the design.