Sealing Performance And Wear Analysis Of Spring Energized Seal In Wide Temperature Range

With the development of technology and the expansion of the scope of human exploration in space,underground and deep sea,advanced precision equipment imposes severe conditions on seals such as wide temperature ranges and low wear,long life and low leakage requirements.Spring energized seal ring is used in aviation,aerospace,vessel and nuclear power due to their low temperature stability,low coefficient of friction,wear resistance,reliable high-speed surface dynamics,stable chemical properties and radiation resistance.However,improper design and manufacture can lead to problems such as excessive seal wear and leak failure.Based on the ABAQUS software,Archard wear theory,Mises stress criterion and Percolation Theory,the spring energized seal ring sealing and wear performance analysis model is established.A method for analyzing and optimizing the performance of sealing rings based on structural strength,leakage characteristics,and friction characteristics was proposed,and the structural design process of spring energized seal ring was given based on the calculation results.The influence of operating parameters such as compression,sealing load and temperature on the sealing performance has been systematically analysed.The seal performance is more sensitive to the operating parameters in the lower compression and sealing load range,and the slight change in the initial compression and sealing load can quickly change the seal leakage rate and friction torque.In the low sealing load range of 0～500k Pa compression is the main influencing factor of sealing performance.In the temperature range of-50 to 65°C,the leakage rate varies less with temperature due to the combined effect of dimensional shrinkage and increased material hardness,after which the leakage rate increases rapidly as the temperature decreases.In view of the sealing performance and energy storage characteristics,a multi-parameter optimisation analysis of the response surface method was carried out on the nine main structural parameters of the shell and the seven main structural parameters of the U-shaped spring,and the main influencing factor on the structural strength of the seal was the internal angle of the left contact lipβ₁,and the main influencing factor on the leakage characteristic was the contact lip width to height ratio a/b.In the improvement of the sealing performance of the seal,priority should be given to increasingβ₁and Decrease a/b.Based on five structural parameters-thickness b_t,total section length h_t,slotted width W,period width T and root radius R_t-regression equations for the spring’s compressive stiffness and elastic compression limit are constructed,and b_t,h_tand W can be changed as a matter of priority when making improvements to the energy storage characteristics.The effect of shell wear on the sealing performance of the seal was studied,comparing the effect of shell structure parameters and material friction wear coefficient on the wear process.Wear can reduce the stress concentration of the shell,the leakage rate increases rapidly with the wear process,then decreases with wear and eventually stabilises,the friction torque decreases with wear and eventually stabilises.The increase of the shell structure parameter a/b and the decrease ofβ₁can significantly reduce the wear of the shell and extend the service life of the seal.The smaller the shell material wear coefficient,the more wear-resistant,the slower the leakage rate rises and the more stable the friction torque decreases the seal is.The seal friction torque test system is built to carry out seal sealing and friction tests in a wide temperature range,and the influence of temperature and seal diameter on the sealing performance and friction performance of the seal is analysed.The test results are consistent with the analytical model with an error of about 10%,which verified the reliability of the analytical model.Comparing the friction mechanism of the seals of two different sizes of packing in sealing friction,it is found that the main wear mechanism of the small size packing shell is abrasive wear with a large amount of wear,while the wear mechanism of the large size packing is fatigue wear with a small amount of wear,so the large packing PTFE is more wear resistant.In this paper,by constructing an analytical model of spring energized seal ring,verified by sealing friction test,the model and analysis results can provide theoretical support for the structural design and optimisation sequence of spring energized seal ring,provide tools for seal wear performance analysis and provide theoretical reference for shell PTFE material improvement,which can help promote the development of low friction long life spring energized seal ring in wide temperature range.