Study On The Sealing Performance Of The Spiral Groove Dry Gas Seal At Rest

The equipment of the spiral groove dry gas seal is in the condition of overhaul,fault,parking,etc.,the dry gas seal is in a static state,and there is obvious difference and correlation between the sealing performance at rest and the rotating state.The dry gas seal contact state and static leak rate are studied for the state of the spiral groove dry gas seal at rest,which reveals the mechanism of the dry gas seal;it has a theoretical guiding effect on the static performance test of the dry gas seal.In this paper,the contact state of the spiral groove seal face at rest is analyzed,and the G-W contact model is used to express the contact of the seal face,and the average clearance between the seal face is obtained.According to the spiral groove narrow groove theory,the governing equation of the gas film pressure between the seal face at rest is obtained.The gas film pressure distribution,opening force and opening force between the end face are obtained by solving the governing equation by analytic method.The sealing performance parameters such as leakage rate at rest are compared with those in dry gas seal technical conditions.The velocity and pressure distributions in the dam area of sealing end face are calculated by finite difference method and compared with the analytical results.The influence of the depth of the spiral groove and the ratio of the groove width to the sealing property is calculated and compared with the groove-less condition,which is in agreement with the theoretical results of the groove-less sealing ring.The calculation results of the finite difference method are similar to those of the analytical calculation.The rationality of the calculation.Aiming at the non-contact state,a method for calculating the Reynolds number of differential pressure shearing composite flow by using composite velocity is proposed.The velocity vector formed by differential pressure flow and shear flow and the characteristic velocity as Reynolds number are used to calculate Reynolds number.Reynolds number,and the composite Reynolds number is equal to 2000 as the critical Reynolds number criterion,to judge whether the pressure difference of the fluid film shears the composite flow is in the laminar flow state or in the turbulent state.Under different working conditions of end face clearance and sealing medium pressure,according to the analytical method,the sealing performance parameters such as film pressure distribution,opening force and leakage rate between the sealing end faces of the spiral groove dry gas seal at rest are solved.The results show that the sealing end face is not open.The film pressure of the spiral groove increases with the increase of the radius,and the film pressure between the sealing end faces with the spiral groove increases rapidly in the dam area with the increase of the radius,and the increase speed in the groove area Slow;the pressure of the sealing medium is constant,the opening force increases with the increase of the gap of the sealing end face;the gap of the sealing end face is constant,the opening force increases with the increase of the pressure of the sealing medium;the pressure of the sealing medium does not change,and the leakage rate varies with the gap of the sealing end face.Increase and increase;the seal end face gap does not change,and the leak rate increases as the pressure of the seal medium increases.When the spiral groove dry gas seal is stationary,its sealing medium pressure and end clearance are constant.With the increase of groove depth,the opening force and leakage rate increase.When the clearance and pressure of the spiral groove dry gas seal are the same,the ratio of groove to platform is zero to infinite,and the opening force and leakage rate between the sealing faces first increase and then decrease;when the ratio of groove to platform is zero and Cao to platform is infinite,the opening force and leakage rate between the sealing faces are the same.