Study On The Influence Of Thermal Characteristics Of Finger Seal Performance Based On Rough Contact

As a flexible high-speed dynamic sealing device,the finger seal has a good application prospect in high-speed sealing parts of aircraft engines and gas turbines.Generally speaking,the finger seal works under high-speed,high-temperature conditions,requiring a long working life,so the device needs to have better sealing performance.In the current published thermal analysis research of finger seal,most of them are the macroscopic studies of finger sealing performance under temperature effect and the influence of friction heat on temperature field distrubution.There are still few studies on the thermal influence mechanism of temperature effect on finger seal.Therefore,the analysis of the thermal effect of the finger seal is carried out to study the influence of temperature on the contact friction state of the finger seal,which is of great significance to the design of the wear life of the finger seal under the actual working condition.Firstly,the basic heat transfer method in finger seal system is analyzed.Thermal contactresistance model of finger seal based on rough contact is studied and corrected.According to the modified thermal contact resistance model,the effect of rotor speed and ambient temperature on the model are obtained.Then,the thermal analysis boundary conditions are determined,the convective heat transfer coefficient and thermal contact conductivity under various working conditions are calculated,and using the heat flux density simulates the friction heat between the finger boot/rotor contact pair,which provide theoretical bases for the subsequent thermal analysis.Next,based on ambient temperature,rotor speed and friction heat,ANSYS APDL parametric modeling is used to establish a thermal analysis model of the finger seal system,analyze the temperature field changes and explore the effect of pressure drop and rotor speed on the finger boot/rotor contact pressure.Finally,the finger seal is machined and tested for verification.Through the thermal analysis of the contact type involute finger seal,the results show that the influence of thermal effect on the finger seal can not be ignored,and the following conclusions are drawn:with the increase of the rotor speed and pressure drop,the maximum temperature of the finger boot rises;after considering the thermal effect,the maximum contact pressure of the finger boot is reduced,so the contact state of the contact pair changes;although the ambient temperature has little effect on the contact state,as rotor speed and pressure drop increase,the contact state of the finger boot/rotor changes greatly.And the performance test results show that,when the thermal effects are considered,theoretical leakage of finger seal is closer to the test result,which verifies the necessity of considering the thermal effect and the rationality of the thermal analysis method.These provide important references for the design of finger seal performance under high temperature and high speed conditions.