钻井泥浆泵柱塞V形圈密封失效仿真分析

Sealing failure analysis of drilling mud pump plunger V-seal ring based on FEM

柱塞密封作为钻井泥浆泵关键部件,在深井和高压工况下,柱塞密封经常出现密封失效问题,而导致钻井泥浆泵工作效率低,甚至出现安全事故。本文通过建立二维轴对称仿真分析模型,讨论了密封过盈量、轴向压紧力、密封圈个数对柱塞密封性能的影响。结果表明:影响密封能力的程度依次为:轴向压紧力最大,其次为密封过盈量,密封圈个数最小;柱塞V形密封圈的密封能力随压紧力的增加呈等倍增长的趋势;增加密封圈个数并不能增加密封能力,第一道密封圈起到密封关键作用,并且其肩部的Von Mises应力非常大,也是最先遭到破坏的;密封过盈量小于0.4mm时,密封能力不会发生变化;轴向压紧力达到15MPa后,密封圈的Von Mises应力急剧上升,继续增加轴向压紧力容易导致密封圈破坏,发生密封失效。

Plunger seals are key components in drilling mud pumps. Under deep well and high pressure conditions, plunger seals often fail, which leads to lower drilling mud efficiency and even safety accidents. In this paper, a two-dimensional axisymmetric simulation model is established to analyze some principal factors, including sealing interference, axial compression force and the number of V-seal ring, which will affect the performance of plunger sealing. Results obtained show that, among the influence factors, the axial compression force has the greatest influence, followed by sealing interference, and the number of V-seal ring has the least effect. The sealing capacity of plunger seals has the double increasing trend with the increase of axial compression force. Adding the number of V-seal ring cannot increase the sealing ability. The first V-seal ring plays a key role in the sealing process, meanwhile, its shoulders has ultrahigh Von-Mises stress, so it is also most damaged. Sealing capacity will not be changed under 0.4 mm sealing interference, the Von-Mises stress of V-seal ring has sharp rising after 15 MPa compression force, so if continue to increasing the compression force, it will lead to the damage of V-seal ring, and making the plunger seal failure eventually.