O型橡胶密封圈高压氢气环境中特性表征

Characterization of rubber O-ring seal in high-pressure gaseous hydrogen

高压氢系统中橡胶O型圈密封结构直接与高压高纯氢气接触,常会发生氢的侵入和溶解继而造成橡胶溶胀,但吸氢膨胀对其密封性能的影响鲜有报道。为解决这一问题,提出了耦合氢致应变的橡胶超弹性本构模型;然后基于有限元软件ABAQUS,通过编写用户材料子程序(UMAT),建立了考虑吸氢膨胀效应的高压氢气橡胶O型圈密封有限元模型,同时对模型进行了验证。并基于该模型研究了吸氢膨胀对高压氢气下橡胶O型圈密封特性的影响。结果表明:吸氢膨胀提高了密封面上的接触应力,利于密封条件的形成;但同时也增加了O型圈截面的高度和面积以及O型圈的Mises应力,加剧了橡胶O型圈出现裂纹的倾向,降低了密封可靠性。在设计高压氢气橡胶O型圈密封结构的预压缩率和沟槽高度时应充分考虑吸氢膨胀效应的影响,以避免出现O型圈应力过大或挤出失效。

Rubber O-ring seal in high-pressure hydrogen system swells due to hydrogen absorption and dissolution after direct exposure to high pressure and high purity gaseous hydrogen.Few works are available in literature on swelling effect on seal performance.A constitutive model of rubber hyperelasticity coupled with hydrogen-induced strain was proposed.Finite element software ABAQUS and user material subroutine(UMAT)program were used to establish a finite element analysis model of hydrogen-swelled rubber O-ring seal in high-pressure hydrogen.Effect of swelling on O-ring seal performance was further studied with the developed model.Results showed that seal contact stress was increased by swelling,which is beneficial to maintain seal performance.However,hydrogen swell increased height and area of O-ring cross section and Mises stress of O-ring,which may make it more susceptible to crack and less reliable of seal quality.Therefore,design pre-compression ratio and groove of rubber O-ring seal structure in high-pressure hydrogen shall consider hydrogen swelling influence in order to avoid occurrence of high stress and O-ring extrusion.