Performance Analysis And Optimization Of The Extended Rotary Fingertip Seal

Fingertip seals have good flexibility characteristics and smaller leakage characteristics than grate seals and brush seals,making them have great application pcotental in uajor equipment such as aviation imdustry and engineering vehicles.The original delign of the fingertip seal is aimed at the sealing of relatively targe diameter slafts However,in practical applications,there is a demand for ultra-high-speed small-dinmeter fingertip seals.At this time,if the traditional lingertip seal structure continues to be used,its flexibility will be greatly reduced,the wear will be further intensified.To this end,this paper conducts research on the small-diameter extended rotating fingertip seal structure,and explores its application prospects and performance characteristics,providing a certain theortical basis for advanced fingertip seal technology,This paper focuses on the theoretical research and related analysis of the C-C composite material extended routating fingertip seal.The main research contents and conclusions are as follows:1.Firstly,the structure and working principle of the involute extended rotary fingertip seal are analyzed,and then the quasi dynamic pcrformance numerical simulation analysis model of the extended rotary fingertip seal is created by ANSYS APDL.The performance.characteristics of the extended rotary fingertip seal under different working conditions are studied,and compared with that of the conventional fingertip seal,and the performance differences between the two are analyzed.The research results show that under the same structural parameters,when the rotation speed of the rotor increases,the sealing performance of the extended rotating fingertip seal gradually improves,the leakage rate shows significant decrease trend,and the wear rate shows a significant increase.The trend is the same as the change trend of the performance law of traditional fingertip seals;at the same time,when the radial runout of the rotor increases,the wear performance and seal performance of the two configuration fingertip seals gradually deteriorate,and the wear rate and leakage The rates are showing a clear upward trend,but the sealing effect of the extended rotating fingertip seal is far better than the sealing effect of the traditional fingertip seal,which shows that the extended rotating fingertip seal is more suitable for high-speed working conditions,therefore,with the help of the excellent wear resistance of C-C composite materials,it has great application prospects in terms of improving the sealing characteristics of the extended rotating fingertip seal.2.Based on the finite element model of the extended rotary fingertip seal,a performance simulation model is established under the dynamic working condition of the fingertip seal.By applying the continuous periodic sinusoidal displacement excitation to simulate the existence of the unbalanced force of the rotor,the influence of the assembly clearance of the fingertip and the parameters of different working conditions on the dynamic performance of the extended rotary fingertip seal is studied.The research results show that under the condition that the rotor is excited by periodic sinusoidal displacement,the leakage gap of the fingertip seal also exhibits periodic variation characteristics;there is an appropriate gap between the fingertip piece and the stator,which is conducive to the extended rotating fingertip seal.Meanwhile,when the rotor rotation speed is less than its "specific" speed,as the rotor speed increases,the amplitude of the displacement response of the fingertip sealing shoe increases,and the amplitude of the leakage rate and the rate of wear both increase trend,but when the rotor rotation speed exceeds its"specific" speed,the amplitude of the leakage rate of the extended rotating fingertip seal shows a downward trend with increasing speed,and the wear rate is the opposite;in addition,as the upstream and downstream as the pressure difference increases,the leakage gap of the extended rotating fingertip seal increases,and both the dynamic leakage rate and the wear rate increase.3.Based on the Nash game theory to solve the multi-objective optimization problem of the extended rotating fingertip seal,a game optimization model of the extended rotating fingertip seal was established,and considering the requirements for performance preference in engineering practice,an efficient,an optimization algorithm that has high decision-making ability and can solve conflicting optimization goals.First,based on the uniform design test method and the DPS data processing system,the structure optimization data sample combination of the fingertip seal is obtained,and the leakage rate value and wear rate value of each sample are obtained by using the finite element model,with low leakage and low wear as the optimal design Objective,through NASH optimization algorithm based on BP neural network,Nash game theory,genetic algorithm to optimize the structure of the extended rotating fingertip seal,to obtain the optimal configuration within the range of structural parameters.Meanwhile,the general weighted optimization algorithm is used to optimize the structure of the outreaching rotating fingertip seal,and then the performance comparison and analysis of the NASH optimization results,weighted optimization results and excellent sample points are performed.The results suggest that the NASH optimization algorithm is more suitable for outreaching rotating fingertips.The structure of the seal is optimized,the performance of the obtained optimal structure is more superior,and the optimization algorithm has high stability.