Rolls-royce Corporation

Bmw Rolls-royce Gmbh

Neil M Evans

Thomas Schillinger

Peter J Maggs

Stephen H Hill

Paul Hayton

Steven M Bagnall

A shroudless turbine rotor blade of the type having a platform damper interface, is provided with at least one slot which extends from the aerofoil side of a platform flow boundary to a point in the root. The slot extends between opposing flanks of the blade so as to divide the platform and partially divide the root. The segregated root is made more flexible by the slot which provides for greater platform vibratory amplitudes for a given length of root. The increased platform motion provides for improved dampability when the blade vibrates. The slot also provides a pair of confronting platform surfaces which are urged into mutual contact by centrifugal load acting on the blade to create an additional damping interface.

Split shank rotor blade

In connection with a turbine rotating disk with disk grooves, constituted by disk fingers, for receiving turbine blades, as well as with measures for guiding a cooling air flow from a chamber located in front of the disk to one behind the disk, a cooling air transfer channel is provided in at least some of the disk fingers, which respectively starts at the front disk face, and makes a transition into a cooling air exhaust channel, also essentially extending in the radial direction in the disk finger, whose outlet opening on the rear disk face side lies closer to the disk axis than the disk ring section, which has the disk grooves and is widened in the disk axial directions. By means of this it is possible to convey a larger cooling air flow which, in an advantageous manner, indirectly aids the cooling of the disk in the area of the disk grooves.

Turbine rotor disk

Gas turbine blade having improved thermal stress cooling ducts

There is provided an aerofoil 11 having a passage 17 supplied with cooling fluid from passage 13. When the leading edge area 14 of the aerofoil 11 erodes/corrodes the passage 17 becomes exposed so that the cooling fluid effects film cooling of the leading edge area.

Aerofoil cooling

A shrouded aerofoil assembly such as a turbine rotor for a gas turbine engine has a multiplicity of blades with tip shrouds circumferentially distributed around a rotor disk. Inevitably, in use, the assembly vibrates and must be designed so the potentially most dangerous vibratory modes occur outside the engine speed range. The proposed arrangement has a number of neighbouring blades sharing a common shroud segment. Adjacent shroud segments are interlocked by Z-notch abutments. Blade assemblies have sufficient pre-twist load to maintain frictional contact in the interlocks over the speed range to maintain damping constraints.

Shrouded aerofoils

In a gas turbine firtree root tooth structure in which a firtree root is retained in a shaped slot in a turbine rotor disc by virtue of teeth cooperating with notches in the slot, the bearing surface of a root tooth is barrelled against a planar surface of the respective notch so as to give point contact against that surface, whereby, under load, the barrelled surface crushes so as to override pitch tolerances and even out load distribution. If the barrelling is located at or in the vicinity of the tooth face center, the tendency of the tooth to crack under repeated loadings is minimized.

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Bristol, United Kingdom

Neil M Evans