Abstract: A dynamic sealing assembly for a rotating shaft to seal an forward portion of the shaft from an aft portion of the shaft, comprises: a stationary member that has an aperture with a spiral grooved aperture surface that passes through it to receive the shaft; and generally linear shaft surface undulations between the forward and aft portions of the shaft that are at least partially within the sealing member aperture; wherein rotation of the shaft causes the undulations to propagate fluid from between the rotating shaft and the aperture into the grooved aperture surface back toward the forward portion of the shaft.

Abstract: Combustion equipment for a gas turbine engine operating on the pre-mix lean combustion bases comprises a flame tube having a plurality of alternately arranged main and pilot air ducts each having a respective fuel injector and receiving axially directed air from downstream of part span outlet guide vanes. The fuel and air in each duct are substantially pre-mixed before entry into the flame tube and the outlets of the pilot ducts direct the fuel and air mixture into the recirculation zone in a single vortex. At engine idle the air fuel ratio (AFR) is substantially stoichiometric to prevent the formation of unburnt hydrocarbons (UHC) and carbon monoxide (CO). As the engine accelerates the fuel flow to the pilot air ducts remains near constant so that the AFR in the re-circulation zone progressively weakens, and fuel is introduced into the main air ducts, the outlets of which direct the air fuel mixture into the flame tube with a substantial downstream component.