Improving the reliability of radial face seals of aircraft engine rotor supports

The article presents an advanced radial face contact seal with increased operational life. High efficiency of the radial mechanical seal is ensured by the joint application of the hydrostatic and hydrodynamic lubrication principles. The hydrodynamic effect is achieved by applying the structure of fine grooves on the rotor hub. The dependence of the flow force value in the slot for a fixed-size gap on the rotor speed is presented. A prototype has been made and tested on a dynamic test bed intended for the realization of operating conditions of support seals making up a part of an aircraft engine. The results of theoretical and experimental studies are presented. Ways of improving the seal reliability due to improving the surface mechanical properties are proposed. A pattern of the development of a functional failure of the seal assembly is presented. The most adverse operating conditions and the main reasons of increased wear of the sealing surfaces are indicated.  Methods of achieving high anti-friction characteristics of contact surfaces by applying nanostructured nonporous chrome-diamond coatings are proposed. Issues concerning the creation of advanced coatings with a positive gradient of depth mechanical properties are discussed. Anti-friction, anti-seize silver-diamond coatings and the use of diffusion molecular reinforcement technology are at the basis of the production of advanced coatings. The paper indicates the importance of anti-friction and extreme-pressure additives contained in the oil.