Rolls-Royce Limited

About: Rolls-Royce Limited is a based out in . It is known for research contribution in the topics: Gas compressor & Rotor (electric). The organization has 624 authors who have published 623 publications receiving 10751 citations. The organization is also known as: Rolls Royce Limited.

Vibration damped rotor blades for turbomachines

Abstract: A blade for a turbomachine having an aerofoil portion and a root portion. The blade is provided with a vibration damper for damping a predetermined vibration of the blade. The damper comprises a closed chamber 14 within the aerofoil portion 13 adjacent the tip of the blade, and liquid 15 within the chamber 14. The volume of liquid 15 is less than the volume of the chamber 14. The chamber 14 is shaped, positioned, and aligned relative to the blade, so that in use the liquid 15 is constrained to form a column which oscillates in the chamber 14 in radial directions and in the same directions as the vibration to be damped. The volume, mass, and viscosity of the liquid are all chosen in relation to the frequency vibration (W B ) of the vibration to be damped and the rotor speed (W E ) so that, in use, the length (L) of the column of liquid is such that ##EQU1## where R=the blade tip radius. In this way the liquid 15 is caused to oscillate, under centrifugal loads, at a natural frequency which matches, or is close to, the resonant frequency of the vibration to be damped.

Gas turbine engine gas flow ducts

Abstract: A ducted fan gas turbine engine power plant has an augmenter air intake and a flow mixer for selectively mixing the augmenter air with the remaining engine flows.

Computation of convective laminar-flow in rotating cavities

Abstract: Numerical predictions are presented for the centrifugally driven free convection in a sealed rotating cavity and for the buoyancy-affected flow through a cavity with an inner cylindrical source and an outer cylindrical sink. Results for a sealed cavity filled with a high-viscosity silicone oil are in good agreement with previously published experimental measurements of the mean Nusselt number. When the heat transfer is conduction-dominated the results away from the cylindrical surface agree with Dorfman's (1968) similarity solution, but as convection becomes important they depart from this solution. In an air-filled cavity, for both the free convection and radial outflow cases, the results away from the cylindrical surface are generally in reasonable agreement with Chew's (1982) similarity solution, although property variations and radial heat conduction do cause some departure from this solution. The extent of the region in which the heat transfer was influenced by the presence of the cylindrical surface, and the Nusselt number distribution in this region are shown to be sensitive to the thermal boundary conditions imposed on this surface.

Shroud structure for a gas turbine engine

Abstract: A shroud assembly is pneumatically operated to adjust the clearance between the shroud segments and the tips of the rotor blades of an associated rotor. The assembly comprises a casing to which is secured a wall member which defines a chamber whose pressure may be varied by a valve. The wall member carries shroud segments some of which define the static wall with which the rotor blades co-operate. In order to allow proper movement of the shroud segments the support means which carry the segments from the wall are arranged to be small in axial extent compared with that of the wall.