Sealing performance analysis of multi-stage step seal
In order to study the transformation law of sealing performance under the influence of back pressure,a two-dimensional axisymmetric model was established by taking the two-stage step seal as an example.The influence of back pressure on sealing performance from the perspective of macroscopic structural mechanics was studied.Considering the roughness and cavitation effects,a fluid-solid coupling mixed elastohydrodynamic lubrication model was built,and the cause of back pressure was further analyzed from the perspective of the sealing mechanism.The experimental results show that at the macro level,as back pressure increases,the contact length of the first-stage step seal decreases and gradually loses its sealing effect,and the contact pressure concentrates on the lip,increasing its peak value and making it more vulnerable to fatigue and wear.The O-ring of the second-stage step seal transfers the pressure to the sealing ring effectively,so that the contact pressure increases and the pressure peak moves outward,leading to increased friction resistance.In terms of the sealing mechanism,the medium leakage of the first-stage step seal,the medium backflow of the second-stage step seal,and the net leakage difference of the two stages of step seal promote the formation of back pressure.Back pressure causes an unstable total friction force between instroke and outstroke,which makes the equipment unable to run smoothly and difficult to control.
万方数据
维普
