Research On Performance Test Methods For High Temperature Sealing

With the rapid development of fast flying equipment,high temperature sealing is particularly important and has become one of the main bottlenecks restricting its development.The installation location is in the extreme envi-ronment of high temperature oxidation,which greatly increases the design dif-ficulty of high temperature seals.High temperature sealing performance di-rectly relates to whether the equipment can meet the design requirements.The effect of different structural parameters on its elasticity,sealing and thermal insulation properties was investigated for the high temperature baseline seals used at the active control panels.Parametric modeling and static simulation of braided spring tubes with high temperature baseline seals.The effects of ring density,wire diameter,number of braided strands,and temperature on the resilience of the braided spring tube were investigated.The fatigue life at a high temperature of 1000°C was calculated.The research results show that under the premise of the de-sign requirements of the braided spring tube,the braided spring tube with double loop braiding has a good performance with a ring density of 0.05 and a wire diameter of 0.32 mm.Referring to the porous medium model,the flow and heat transfer mech-anism of air flowing through the high temperature baseline seal was analyzed,and the mathematical model of the flow and heat transfer of air in the high temperature baseline seal was introduced.The study found that the Blake-Kozeny equation is a good predictor of leak characteristics of seals.The first law of thermodynamics is applied to the heat transfer analysis of porous media.The complex flow equation considering the gas-solid two-phase heat transfer is introduced.The influence of air leakage on the heat insulation characteristics is obtained by this equation.The computational fluid dynamics software Fluent was used to simulate the flow of air in a high temperature baseline seal,and the built-in porous me-dia model was used to simplify the baseline seal.Through the steady state calculation and transient calculation,the structural parameters of the baseline seal were studied for sealing and thermal insulation performance.It is found that the amount of compression has a great influence on the sealing and heat insulation performance.The leakage amount is linearly proportional to the in-let pressure,and the outlet temperature has a second-order nonlinear relation-ship with the inlet pressure.A high-temperature sealing test bench was built to conduct an experi-mental study on the high-temperature baseline seal.The experimental results are well matched to the simulation results.The experimental results show that the high-density sample has better sealing and heat insulation effect under the compression of 30%.However,the baseline seal showed a permanent defor-mation problem after the high temperature test,and the fiber material used for the high temperature sealing showed expansion hardening after the high tem-perature test.Theoretical analysis,simulation analysis and experimental research can well predict the sealing and thermal insulation performance of high tempera-ture baseline.The research method of this paper can provide reference for subsequent performance improvement.