Rotating Intershaft Brush Seals For Sealing Between Two Rotating Shafts

The pursuit of high Mach number flight presents several challenges to the airframe and engine design engineers. Most obvious is the resulting high temperatures encountered as the aircraft approaches Mach 3 and above. The encountered high temperatures and shaft speeds of engines require rethinking in the areas of material selections, component design and component operating life. For the engine design engineer, the challenge lies in components that make up the bearings and seals region of the aircraft engine that encounter severe operational requirements. High operating temperatures and pressures and longer cycle durations are among these. The seals, which are used to seal the bearing compartments, or sumps, from high airflow ingestion, maintain a favorable air pressure gradient, and minimize engine lubricant loss, is such a component. In the area of sump compartment sealing, one of the most difficult sealing applications is the sealing of an engine's rear sump. Normally this sump will need some method of sealing between two rotating shafts. For the sealing of sumps, between rotating shafts, in gas turbine engines, there are two technologies that have been used up to the present time. These technologies are:  Carbon Seals  Labyrinth Seals Rotating Brush Seals to seal between shafts offer another technology.