Jixie qiangdu (Jan 2019)
CONTACT STRENGTH ANALYSIS OF FINGER SEAL CONSIDERING THERMAL EFFECT
Abstract
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. However,Under high-speed and high temperature conditions, friction heat and ambient temperature have a significant impact on contact strength and sealing performance of the finger seal. So exploring its influence mechanism becomes the key problem of finger seal design. Therefore,based on the actual working conditions,converting the friction heat to the heat flux density boundary condition,considering working temperature,a coupled thermal structural analysis model of the finger seal system is built,and the influence of thermal effect on the contact strength of the finger seal/rotor pair is studied,then it verified by tests. The results show that friction heat has an important influence on the contact strength of the sealing pair at high speed. Under normal temperature conditions,the local temperature of the finger seal rises above 370℃ because of friction effect,and the contact pressure at finger foot/rotor friction pair increases by nearly 10%. Under high temperature conditions,when the thermal effects are considered,local contact pressure is reduced by 90%. The performance test results show that,the maximum error between theoretical and test result is only 16.5% under pressure of 0.4 MPa,while the maximum error reaches 72.8% when thermal effect is not considered,which verified the necessity of thermal effect and the rationality of thermal analysis method. So the study provides an important reference for the design of finger seal under high temperature and high speed conditions.
