Research Of The Performance Of Carbon Fiber Brush Seal

Brush seal is a new type of flexible seal with high efficiency developed in recent years.Its performance is superior to that of traditional labyrinth seal.But at present,the common brush seal has the problems of large leakage and limited working conditions.According to the characteristics of main bearing chamber,in order to meet the sealing requirements of high temperature,reversible and low leakage rate,and to improve the traditional radial brush seal,a new type of brush seal based on carbon fiber material,i.e.L-shaped flexible wire seal structure,was proposed.Its flow field,temperature field,leakage and heat transfer performance were numerically analyzed and tested.Based on porous medium theory,the momentum equation and continuity equation of"L" flexible wire brush seal are modified.The numerical model of "L" flexible wire brush seal was established by using Fluent software and optimizing calculation of axisymmetric structure.The velocity field,pressure distribution and temperature distribution of "L"flexible wire brush seal are obtained by conjugate calculation and analysis.The leakage and heat transfer characteristics of the "L" structure and the traditional radial brush seal were compared and analyzed,and the excellent heat transfer performance of carbon fiber brush wire compared with the traditional hard wire material was verified.The evaluation indexes of heat transfer and leakage characteristics of "L" flexible wire brush seal are determined.Based on the numerical model,the effects of structural parameters,working conditions and installation parameters on the leakage rate,heat flux and heat release ratio of "L" flexible wire brush seal were analyzed.Orthogonal test was designed to analyze the influence of structural parameters on the performance of "L" flexible wire brush seal,and the optimal value of structural parameters was determined.The effects of structural parameters on the leakage characteristics of "L" flexible brush seals are as follows:the porosity of brush bundle,the thickness ratio of brush bundle,the clearance ratio of back plate,the clearance ratio of front plate,the diameter of brush wire and the length of brush wire.A test device of "L" flexible wire brush seal was developed.The manufacturing process of carbon fiber brush seal was explored.The test bench was set up.Static and dynamic pressure tests were carried out respectively to determine the leakage rate of the seal with different structural and operational parameters.The experimental structure is basically consistent with the numerical simulation results,which verifies the accuracy and reliability of the numerical analysis results.The rationality of this new type of brush seal structure is verified by theoretical calculation analysis and experimental verification on the performance of "L" flexible brush seal.It can provide research ideas and theoretical basis for structural design and performance optimization of subsequent flexible brush seal.