Study On Wear Characteristics Of Brush Seal And Their Impact On Leakage Characteristics

With the continuous development and progress of turbine machinery,sealing technology has become more and more important.As a relatively new type of sealing technology,brush seal is widely used in aircraft engines,steam turbines,and gas turbines.Compared with the traditional grate tooth seal,the leakage amount is significantly reduced due to the flexible contact between the brush wire and the rotor.However,the unique structural and material of the seal wire and high speed,high temperature and high-pressure working environment cause the indispensable wear of the brush wire during the process of brush sealing and weakening the sealability.This study aims to wear characteristics of brush seal and their effects on leakage characteristics.First of all,to research the calculation method of brush seal wear and leakage characteristics.After analyzing the wear in the process of the brush seal,determined the worn form is adhesive wear,and the calculation formula of the wear amount and wear rate is derived based on a series of basic assumptions.The numerical calculation method of leakage characteristics uses a porous media model for calculation.After the brush beam area of the brush seal is treated as a porous medium domain,a control equation is established.After determining the thickness and porosity of the brush beam area,a leakage flow model of the brush seal is established.After the comparison,the thickness and porosity of the brush bundle were corrected to verify the feasibility of the model.After determining the numerical calculation method of the wear of the brush seal,the influence of the change of the arrangement angle of the brush wire on the porosity during the wear process is analyzed,and a calculation method considering the leakage characteristics of the wear brush seal is established.Secondly,numerically calculate the wear characteristics of the brush seal,study the influence of different structural parameters,interference,and rotation speed on the wear characteristics of the brush seal,and conduct a sensitivity analysis.The results show that the initial increase in the wear rate of the brush seal is faster.After a while,it reaches stability,and changes in various structural parameters will affect its wear characteristics.Calculate the leakage characteristics of the brush seal,analyze the impact of changes in various structural parameters on the leakage of the brush seal,and analyze the pressure distribution and speed distribution of the brush seal under different values of the same structural parameter,to carry out the leakage characteristics of the brush seal to sum up.Finally,using the calculation method of brush seal leakage characteristics considering wear,after selecting the calculation domain,meshing and determining the boundary conditions,the influence of different structural parameters,interference,and rotation speed on the wear leakage characteristics is studied.It shows that when considering wear,the brush seal increases with time,structural parameters,interference,and speed will affect the leakage of the brush seal when considering wear,the change trend of leakage amount when wear is considered is the same as the change trend of wear amount.Different structural parameters,interference,and the changing trend of the rotation speed wear amount with time reflect the changing trend of leakage amount when considering wear.