Flow Field Analysis And Performance Study Of Double Groove-step Groove Dry Gas Seal

Dry gas sealing technology is widely used in rotating machinery and equipment due to its low loss,low leakage,and long life.As the operating environment of the sealing system moves towards high-parameter working conditions,the research on the groove structure with strong comprehensive sealing performance and good leakage reduction effect is of great significance.Both the stepped convergent groove and the double groove have the effect of reducing leakage,in order to solve the problems of poor sealing performance and large leakage of dry gas seal system at high speed,a double groove-stepped groove face seal structure was proposed.CFD method was used to simulate the sealing performance of three groove types.By studying the pressure field,temper ature field,and velocity field of three different groove types,and taking the leakage rate and stiffness to leakage ratio as the optimization objectives,the influence of stepped groove and double groove on sealing performance was compared and analyzed.It is not difficult to find that the sealing performance of the stepped groove is poorer than that of the double groove-stepped Groove,so the stepped groove is no longer studied.On this basis,the structural parameters and operating parameters of ordinary spiral groove and double groove-stepped groove are studied.Selecting two groove types,ordinary spiral groove and double groove step groove,has good effect of reducing leakage,and has good structural parameters and working condition parameters for comprehensive sealing performance.The results show that the seal performance of dry gas seal is better when the groove depth is 6μm,the helix angle is 15°,the number of grooves is 12,and the film thickness is 3.5μm.Compared with pressure,the influence of rotating speed on sealing performance parameters is more significant.Under the condition of high temperature 、high speed and low pressure,compared with ordinary spiral groove dry gas seal,the bearing capacity of double groove stepped groove dry gas seal is slightly affected,while the stiffness to leakage ratio is increased by 21.74%,and the leakage rate is reduced by 27.45%.Using ANSYS Workbench software to simulate the stress and strain of spiral groove and double groove-step groove sealing ring under one-way heat-fluid-solid coupling.By transferring the flow field analysis module,the thermal strength coupling analysis module,and the structural field analysis module to the Workbench platform,the pressure load and the temperature load are l oaded at the same time to realize information transfer of thermal fluid solid coupling.Based on the analysis of the stress and strain of the sealing ring under different working conditions,the results show that,in the case of consistent structural param eters,considering the stress and deformation,the sealing material of the moving ring is silicon carbide,and the sealing material of the static ring is graphite.As the pressure increases,the deformation of the seal ring increases,and the maximum stress increases.As the rotation speed increases,the temperature has a significant influence on the seal ring,and the deformation and maximum stress of the seal ring are reduced.However,the maximum stress and strain of the sealing ring of different groove types are at the groove root.Under the same working conditions and structural parameters,considering the comprehensive influence of pressure and temperature,the deformation and maximum stress of the double groove-stepped groove seal ring are smaller than that of a single spiral groove.In short,under the conditions of high temperature,high speed and low pressure,the sealing ring of the double groove-step groove can operate more stably.