Patent Application
20180051579
This disclosure relates to gas turbine engines, and more particularly to stator vane arrangements for gas turbine engines.
A gas turbine engine typically includes a rotor assembly which extends axially through the engine. A stator assembly is radially spaced from the rotor assembly and includes an engine case which circumscribes the rotor assembly. A flow path for working medium gasses is defined within the case and extends generally axially between the stator assembly and the rotor assembly.
The rotor assembly includes an array of rotor blades extending radially outwardly across the working medium flowpath into proximity with the case. Arrays of stator vane assemblies are alternatingly arranged between rows of rotor blades and extend inwardly from the case across the working medium flowpath into proximity with the rotor assembly to guide the working medium gases when discharged from the rotor blades. Some stator vane assemblies, such as those located between adjacent low pressure compressor or fan rotors, include an outer shroud fixed to a casing and a plurality of stator vanes along with an inner shroud cantilevered off of the outer shroud.
The stator vanes are rigidly fixed to the inner shroud and outer shroud and are thus configured with aeromechanical tuning of vibratory modes, which often results in the vane deviating from an optimal aerodynamic shape.
In one embodiment, a stator assembly for a gas turbine engine includes an arcuate shroud including a shroud pocket, the shroud pocket having a shroud slot extending therethrough. A stator vane is insertable into the shroud pocket and includes a vane slot extending therethrough. A strap extends through the shroud slot and the vane slot to retain the vane to the shroud.
Additionally or alternatively, in this or other embodiments a volume of potting is located at the shroud pocket to retain the stator vane thereat.
Additionally or alternatively, in this or other embodiments the potting is a rubber material.
Additionally or alternatively, in this or other embodiments the potting includes a grommet located at the shroud pocket.
Additionally or alternatively, in this or other embodiments the shroud pocket includes a pocket sidewall and a pocket base.
Additionally or alternatively, in this or other embodiments the shroud slot extends through the pocket sidewall.
Additionally or alternatively, in this or other embodiments the stator vane is inserted in two shroud pockets of two shrouds, with a strap extending through a vane slot and a pocket slot at each shroud of the two shrouds.
In another embodiment, a stator and case assembly for a gas turbine engine includes a case defining a working fluid flowpath for the gas turbine engine, and a stator assembly secured at the case. The stator assembly includes a plurality of stator segments arranged circumferentially about an engine axis. Each stator segment includes an arcuate shroud including a shroud pocket, the shroud pocket having a shroud slot extending therethrough, a stator vane insertable into the shroud pocket and including a vane slot extending therethrough, and a strap extending through the shroud slot and the vane slot to retain the vane to the shroud.
Additionally or alternatively, in this or other embodiments a volume of potting is located at the shroud pocket to retain the stator vane thereat.
Additionally or alternatively, in this or other embodiments the potting is a rubber material.
Additionally or alternatively, in this or other embodiments the potting includes a grommet located at the shroud pocket.
Additionally or alternatively, in this or other embodiments the shroud pocket includes a pocket sidewall and a pocket base.
Additionally or alternatively, in this or other embodiments the shroud slot extends through the pocket sidewall.
Additionally or alternatively, in this or other embodiments the stator vane is inserted in two shroud pockets of two shrouds, with a strap extending through a vane slot and a pocket slot at each shroud of the two shrouds.
In yet another embodiment, a gas turbine engine includes a combustor and a stator and case assembly in in fluid communication with the combustor. The stator and case assembly includes a case defining a working fluid flowpath for the gas turbine engine and a stator assembly secured at the case. The stator assembly includes a plurality of stator segments arranged circumferentially about an engine axis, each stator segment including an arcuate shroud including a shroud pocket, the shroud pocket having a shroud slot extending therethrough, a stator vane insertable into the shroud pocket and including a vane slot extending therethrough and a strap extending through the shroud slot and the vane slot to retain the vane to the shroud.
Additionally or alternatively, in this or other embodiments a volume of potting is located at the shroud pocket to retain the stator vane thereat.
Additionally or alternatively, in this or other embodiments the potting is a rubber material.
Additionally or alternatively, in this or other embodiments the potting includes a grommet located at the shroud pocket.
Additionally or alternatively, in this or other embodiments the shroud pocket includes a pocket sidewall and a pocket base, the shroud slot extending through the pocket sidewall.
Additionally or alternatively, in this or other embodiments the stator vane is inserted in two shroud pockets of two shrouds, with a strap extending through a vane slot and a pocket slot at each shroud of the two shrouds.
The subject matter which is regarded as the present disclosure is particularly pointed out and distinctly claimed in the claims at the conclusion of the specification. The foregoing and other features, and advantages of the present disclosure are apparent from the following detailed description taken in conjunction with the accompanying drawings in which:
The gas turbine engine 10 further comprises a turbine section 20 for extracting energy from the combustion gases. Fuel is injected into the combustor 18 of the gas turbine engine 10 for mixing with the compressed air from the compressor 16 and ignition of the resultant mixture. The fan 12, compressor 16, combustor 18, and turbine 20 are typically all concentric about a common central longitudinal axis of the gas turbine engine 10.
The gas turbine engine 10 may further comprise a low pressure compressor 22 located upstream of a high pressure compressor 24 and a high pressure turbine located upstream of a low pressure turbine. For example, the compressor 16 may be a multi-stage compressor 16 that has a low-pressure compressor 22 and a high-pressure compressor 24 and the turbine 20 may be a multistage turbine 20 that has a high-pressure turbine and a low-pressure turbine. In one embodiment, the low-pressure compressor 22 is connected to the low-pressure turbine and the high pressure compressor 24 is connected to the high-pressure turbine.
Referring now to
While the following description is in the context of an LPC stator 32, one skilled in the art will readily appreciated that the present disclosure may be readily applied to other stator assemblies including those configured as segmented stators and those configured as full ring stators. Referring now to
Referring now to
In addition to or as an alternative to the arrangement described above with reference to
Referring now to
Utilizing potting material as primary retention of the stator vanes at the outer shroud and the inner shroud allows the stator vanes to be formed from a different material than the outer shroud and/or the inner shroud. For example, the stator vanes may be formed from a composite material while the inner and outer shrouds are formed from a metal material resulting in a considerable weight reduction when compared to an all-metal stator assembly. Further, the potting material provides necessary vibrational damping properties allowing the stator assembly in general and the stator vanes in particular to be formed to an aerodynamically optimized shape. The outer and inner straps, respectively, provide secondary retention of the stator vanes at the shrouds.
While the present disclosure has been described in detail in connection with only a limited number of embodiments, it should be readily understood that the present disclosure is not limited to such disclosed embodiments. Rather, the present disclosure can be modified to incorporate any number of variations, alterations, substitutions or equivalent arrangements not heretofore described, but which are commensurate with the spirit and scope of the present disclosure. Additionally, while various embodiments of the present disclosure have been described, it is to be understood that aspects of the present disclosure may include only some of the described embodiments. Accordingly, the present disclosure is not to be seen as limited by the foregoing description, but is only limited by the scope of the appended claims.
