Patent Application
20090257877
The present invention relates to a gas turbine engine, and more particularly to a rotor blade attachment thereof.
Gas turbine engines often include a multiple of rotor assemblies within a fan, compressor and turbine section. Each rotor assembly has a multitude of blades attached about a circumference of a rotor disk. Each of the blades is spaced a distance apart from adjacent blades to accommodate movement and expansion during operation. Each blade includes a root section that attaches to the rotor disk, a platform section, and an airfoil section that extends radially outwardly from the platform section.
Gas turbine engine rotor blades are typically attached in a rotor disk rim through a fir-tree-type root attachment section. The blades are then locked into place with bolts, peening, locking wires, pins, keys, plates, or other locks. The blades need not fit too tightly in the rotor disk due to the centrifugal forces during engine operation. Some blade movement reduces the vibrational stresses produced by high-velocity airstreams between the blades.
Referring to
A rotor blade for a gas turbine engine according to an exemplary aspect of the present invention includes: an asymmetric attachment section.
A rotor disk for a gas turbine engine according to an exemplary aspect of the present invention includes: a hub; a rim; and a web which extends between said hub and said rim, said rim defines a multiple of asymmetric slots.
A rotor blade for a gas turbine engine according to an exemplary aspect of the present invention includes: an asymmetric attachment section defines a multiple of first lobes and a multiple of first pockets on a first side and a multiple of second lobes and a multiple of second pockets on a second side, at least one of the multiple of first lobes located generally opposite a second pocket and at least one of the multiple of first pockets located generally opposite a second lobe.
The various features and advantages of this invention will become apparent to those skilled in the art from the following detailed description of the disclosed non-limiting embodiment. The drawings that accompany the detailed description can be briefly described as follows:
The HPT section includes a blade outer air seal assembly 16 with a rotor assembly 18 disposed between a forward stationary vane assembly 20 and an aft stationary vane assembly 22. Each vane assembly 20, 22 includes a plurality of vanes 24 circumferentially disposed around an inner vane support 26F, 26A.
The rotor assembly 18 includes a plurality of blades 34 circumferentially disposed around a rotor disk 36 (
Referring to
The rim 44 defines an asymmetrical slot 49 to receive the asymmetric attachment section 50 of the respective blade 34. Each asymmetrical slot 49 defines a first side 49A and a second side 49B. The first side 49A includes a multiple of lobes 64AA, 64AB, 64AC and a multiple of pockets 66AA, 66AB, 66AC. The second side 49B includes a multiple of lobes 64BA, 64BB, 64BC and a multiple of pockets 66BA, 66BB, 66BC. The pocket 66AA is across from the lobe 64BA; the lobe 64AB is across from the pocket 66BA; the pocket 66AB is across from the lobe 64BB; the lobe 64AC is across from the pocket 66BB; and the pocket 66AC is across from the lobe 64BC relative to blade axis B.
A rim section 44S is defined between each of two asymmetric slots 49. The rim section 44S includes the lobe 64BA across from the pocket 66AA; the pocket 66BA across from the lobe 64AB; the lobe 64BB across from the pocket 66AB; the pocket 66BB across from the lobe 64AC; and the lobe 64BC across from the pocket 66AC.
This asymmetrical shape of the asymmetric attachment section 50 and the asymmetrical slot 49 may be formed through EDM, grinding, or broaching, which facilitates the flexibility to shape the fir-tree in a manner that can vary symmetry. The variation in symmetry increases the cross-sectional area of the rim section 44S between each blade asymmetrical slot 49 and the asymmetric attachment section 50 by offsetting the lobes.
The asymmetrical interface reduces shear stress and increase the overall capability of the blade 34 and the rotor disk 36. The reduced stress (
An angled distal end 50E (
A shorter neck length below the platform section 53 is also facilitated by the asymmetric attachment section 50 as underplatform section hardware 72 (illustrated schematically) such as a damper and featherseal may be located adjacent an angled outer diameter 44E of the rims section 44S. That is, the underplatform section hardware 72 is located within the triangular area defined by the angled outer diameter 44E and the platform section 52.
It should be understood that relative positional terms such as “forward,” “aft,” “upper,” “lower,” “above,” “below,” and the like are with reference to the normal operational attitude of the vehicle and should not be considered otherwise limiting.
It should be understood that like reference numerals identify corresponding or similar elements throughout the several drawings. It should also be understood that although a particular component arrangement is disclosed in the illustrated embodiment, other arrangements will benefit from the instant invention.
Although particular step sequences are shown, described, and claimed, it should be understood that steps may be performed in any order, separated or combined unless otherwise indicated and will still benefit from the present invention.
The foregoing description is exemplary rather than defined by the limitations within. Many modifications and variations of the present invention are possible in light of the above teachings. The disclosed embodiments of this invention have been disclosed, however, one of ordinary skill in the art would recognize that certain modifications would come within the scope of this invention. It is, therefore, to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described. For that reason the following claims should be studied to determine the true scope and content of this invention.
