Patent Application
20200173297
The present disclosure relates to gas turbine engines, and, more specifically, to a blade outer air seal of a turbine section or a compressor section.
A gas turbine engine may include a fan section, a compressor section, a combustor section, and a turbine section. A turbine in-use may become unstable and reach high speeds upon the occurrence of a high shaft failing. The turbine may be prevented from reaching excessive speeds using a combination of compressor surge, blade and vane airfoil intermeshing, fuel shutoff, or frictional braking from metal to metal contact of rotating and static hardware. However, if blade and vane intermeshing or fuel shutoff are not viable options, rotor overspeed should be otherwise sufficiently prevented or controlled.
In various embodiments, a rotor overspeed protection (ROP) assembly of a gas turbine engine is provided. In various embodiments, the ROP assembly may comprise an annular blade outer air seal (BOAS) assembly comprising a ROP segment. In various embodiments, the ROP assembly may comprise a stator vane coupled with the BOAS assembly, the stator vane comprising a stator flange disposed about a forward edge portion of the stator vane. In various embodiments, the ROP segment comprises a ROP flange extending in an axially aft direction from a main body of the ROP segment toward the stator vane, wherein the ROP flange is disposed radially inward of the stator flange. In various embodiments, the BOAS assembly comprises a BOAS segment coupled with the ROP segment, the BOAS segment comprising a BOAS flange extending in an axially aft direction from a main body of the BOAS segment toward the stator vane, wherein the BOAS flange is disposed radially outward of the stator flange of the stator vane. In various embodiments, the ROP segment is coupled to a second ROP segment. In various embodiments, the second ROP segment disposed about 180 degrees from the ROP segment about the BOAS assembly. In various embodiments, the BOAS assembly comprises a plurality of ROP segments and a plurality of BOAS segments, wherein the plurality of ROP segments and the plurality of BOAS segments alternate about the BOAS assembly. In various embodiments, the BOAS assembly comprises a plurality of ROP segments disposed about 90 degrees apart about the BOAS assembly. In various embodiments, the stator flange is configured to contact the ROP flange in response to the stator vane rotating about a rear leg of the stator vane in an aft direction. In various embodiments, the BOAS assembly is comprised entirely of ROP segments.
In various embodiments, a gas turbine engine is provided. In various embodiments, the gas turbine engine may comprise a turbine section or a compressor section including a stator vane. In various embodiments, the gas turbine engine may comprise an annular blade outer air seal (BOAS) assembly comprising a ROP segment. In various embodiments, the gas turbine engine may comprise a stator vane coupled with the BOAS assembly, the stator vane comprising a stator flange disposed about a forward edge portion of the stator vane. In various embodiments, the gas turbine engine comprises a ROP flange extending in an axially aft direction from a main body of the ROP segment toward the stator vane, wherein the ROP flange is disposed radially inward of the stator flange. In various embodiments, the BOAS assembly comprises a BOAS segment coupled with the ROP segment, the BOAS segment comprising a BOAS flange extending in an axially aft direction from a main body of the BOAS segment toward the stator vane, wherein the BOAS flange is disposed radially outward of the stator flange of the stator vane. In various embodiments, the ROP segment is coupled to a second ROP segment. In various embodiments, the second ROP segment disposed about 180 degrees from the ROP segment about the BOAS assembly. In various embodiments, the BOAS assembly comprises a plurality of ROP segments and a plurality of BOAS segments, wherein the plurality of ROP segments and the plurality of BOAS segments alternate about the BOAS assembly. In various embodiments, the BOAS assembly comprises a plurality of ROP segments disposed about 90 degrees apart about the BOAS assembly. In various embodiments, the stator flange is configured to contact the ROP flange in response to the stator vane rotating about a rear leg of the stator vane in an aft direction. In various embodiments, the BOAS assembly is comprised entirely of ROP segments.
In various embodiments, a method of manufacturing a ROP assembly is provided. The method may comprise manufacturing a blade outer air seal (BOAS) assembly, wherein the BOAS assembly comprises a ROP segment. The method may comprise coupling a stator vane with the ROP segment, wherein the ROP segment comprises a ROP flange extending in an axially aft direction from a main body of the ROP segment toward the stator vane, wherein the ROP flange is disposed radially inward of a stator flange of the stator vane. The method may comprise coupling the BOAS assembly with an engine case structure of a gas turbine engine. The manufacturing the BOAS assembly may comprise coupling a first ROP segment to a first BOAS segment. The manufacturing the BOAS assembly may comprise coupling a first ROP segment to a second ROP segment.
The foregoing features and elements may be combined in various combinations without exclusivity, unless expressly indicated otherwise. These features and elements as well as the operation thereof will become more apparent in light of the following description and the accompanying drawings. It should be understood, however, the following description and drawings are intended to be exemplary in nature and non-limiting.
The subject matter of the present disclosure is particularly pointed out and distinctly claimed in the concluding portion of the specification. A more complete understanding of the present disclosure, however, may best be obtained by referring to the detailed description and claims when considered in connection with the figures, wherein like numerals denote like elements.
All ranges and ratio limits disclosed herein may be combined. It is to be understood that unless specifically stated otherwise, references to “a,” “an,” and/or “the” may include one or more than one and that reference to an item in the singular may also include the item in the plural.
The detailed description of various embodiments herein makes reference to the accompanying drawings, which show various embodiments by way of illustration. While these various embodiments are described in sufficient detail to enable those skilled in the art to practice the disclosure, it should be understood that other embodiments may be realized and that logical, chemical, and mechanical changes may be made without departing from the spirit and scope of the disclosure. Thus, the detailed description herein is presented for purposes of illustration only and not of limitation. For example, the steps recited in any of the method or process descriptions may be executed in any order and are not necessarily limited to the order presented. Furthermore, any reference to singular includes plural embodiments, and any reference to more than one component or step may include a singular embodiment or step. Also, any reference to attached, fixed, connected, or the like may include permanent, removable, temporary, partial, full, and/or any other possible attachment option. Additionally, any reference to without contact (or similar phrases) may also include reduced contact or minimal contact. Cross hatching lines may be used throughout the figures to denote different parts but not necessarily to denote the same or different materials.
As used herein, “aft” refers to the direction associated with the tail (e.g., the back end) of an aircraft, or generally, to the direction of exhaust of the gas turbine engine. As used herein, “forward” refers to the direction associated with the nose (e.g., the front end) of an aircraft, or generally, to the direction of flight or motion.
As used herein, “distal” refers to the direction radially outward, or generally, away from the axis of rotation of a turbine engine. As used herein, “proximal” refers to a direction radially inward, or generally, towards the axis of rotation of a turbine engine.
In various embodiments and with reference to
Gas turbine engine 20 may generally comprise a low speed spool 30 and a high speed spool 32 mounted for rotation about an engine central longitudinal axis A-A′ relative to an engine case structure 36 via several bearing systems 38, 38-1, and 38-2. Engine central longitudinal axis A-A′ is oriented in the z direction on the provided xyz axis. It should be understood that various bearing systems 38 at various locations may alternatively or additionally be provided, including for example, bearing system 38, bearing system 38-1, and bearing system 38-2.
Low speed spool 30 may generally comprise an inner shaft 40 that interconnects a fan 42, a low pressure compressor 44 and a low pressure turbine 46. Inner shaft 40 may be connected to fan 42 through a geared architecture 48 that can drive fan 42 at a lower speed than low speed spool 30. Geared architecture 48 may comprise a gear assembly 60 enclosed within a gear housing 62. Gear assembly 60 couples inner shaft 40 to a rotating fan structure. High speed spool 32 may comprise an outer shaft 50 that interconnects a high pressure compressor 52 and high pressure turbine 54. A combustor 56 may be located between high pressure compressor 52 and high pressure turbine 54. A mid-turbine frame 57 of engine case structure 36 may be located generally between high pressure turbine 54 and low pressure turbine 46. Mid-turbine frame 57 may support one or more bearing systems 38 in turbine section 28. Inner shaft 40 and outer shaft 50 may be concentric and rotate via bearing systems 38 about the engine central longitudinal axis A-A′, which is collinear with their longitudinal axes. As used herein, a “high pressure” compressor or turbine experiences a higher pressure than a corresponding “low pressure” compressor or turbine.
The core airflow C may be compressed by low pressure compressor 44 then high pressure compressor 52, mixed and burned with fuel in combustor 56, then expanded over high pressure turbine 54 and low pressure turbine 46. Turbines 46, 54 rotationally drive the respective low speed spool 30 and high speed spool 32 in response to the expansion.
Gas turbine engine 20 may be, for example, a high-bypass ratio geared aircraft engine. In various embodiments, the bypass ratio of gas turbine engine 20 may be greater than about six (6). In various embodiments, the bypass ratio of gas turbine engine 20 may be greater than ten (10). In various embodiments, geared architecture 48 may be an epicyclic gear train, such as a star gear system (sun gear in meshing engagement with a plurality of star gears supported by a carrier and in meshing engagement with a ring gear) or other gear system. Geared architecture 48 may have a gear reduction ratio of greater than about 2.3 and low pressure turbine 46 may have a pressure ratio that is greater than about five (5). In various embodiments, the bypass ratio of gas turbine engine 20 is greater than about ten (10:1). In various embodiments, the diameter of fan 42 may be significantly larger than that of the low pressure compressor 44, and the low pressure turbine 46 may have a pressure ratio that is greater than about five (5:1). Low pressure turbine 46 pressure ratio may be measured prior to inlet of low pressure turbine 46 as related to the pressure at the outlet of low pressure turbine 46 prior to an exhaust nozzle. It should be understood, however, that the above parameters are exemplary of various embodiments of a suitable geared architecture engine and that the present disclosure contemplates other gas turbine engines including direct drive turbofans. A gas turbine engine may comprise an industrial gas turbine (IGT) or a geared aircraft engine, such as a geared turbofan, or non-geared aircraft engine, such as a turbofan, or may comprise any gas turbine engine as desired.
Still referring to
With reference to
In various situations, a turbine in use may reach high speeds and may become unstable upon the occurrence of a high shaft failing. Specifically, when a high shaft fails, high pressure turbine 54 may slide aft along gas turbine engine 20 due to a pressure differential between a forward side and an aft side of the high pressure turbine 54. High pressure turbine 54 may slide in an aft direction along gas turbine engine 20 with thousands of pounds of force. The rotor blade 70 of high pressure turbine 54 may contact stator vane 72, causing a portion of forward end 73 of stator vane 72 to break or otherwise fail. Stator vane 72 may in turn rotate aft about a rear leg 75 and cause damage to a further aft portion of gas turbine engine 20. The stator flange 78 may then contact ROP flange 286 of ROP segments 280 and pull ROP flange 286 radially inward. As ROP flange 286 is pulled radially inward, rear BOAS leg 89 (shown on
According to various embodiments, and referring to
In various embodiments, ROP assembly 100 may comprise stator vane 72 coupled to axially adjacent BOAS segment 12.
Referring back to
Referring to
In various embodiments, gap 88 may be configured to house a seal 102. Cooling air from secondary airflow S may tend to leak between BOAS segment 12 and stator vane 72 in response to a pressure differential. Thus, a seal 102 may be disposed between BOAS segment 12 and stator vane 72 to prevent, reduce, and/or control leakage of secondary airflow S through gap 88 into core airflow path C.
According to various embodiments, and with reference to
According to various embodiments, and with reference to
In various embodiments, and with reference to
Referring to
During engine operation, stator vane 72 and ROP segment 280 may be subjected to different thermal loads and environmental conditions. Cooling air may be provided to ROP segment 280 and stator vane 72 to enable operation of the turbine during exposure to hot combustion gasses produced within the combustion area. Secondary airflow S provides varying levels of cooling to different areas of ROP segment 280 around blades 70.
Stator vane 72 may be axially separated from ROP segment 280 by a distance or gap 188. Gap 188 may expand and/or contract (axially and/or radially) in response to the thermal and/or mechanical environment. In addition, gap 188 may expand and/or contract (axially and/or radially) as a result of thermal, mechanical, and pressure loading imparted in ROP segment 280, stator vane 72, and/or supporting structure during various transient and steady state engine operating conditions.
In various embodiments, gap 188 may be configured to house seal 102. Cooling air from secondary airflow S may tend to leak between ROP segment 280 and stator vane 72 in response to a pressure differential. Thus, a seal 102 may be coupled with and disposed between ROP segment 280 and stator vane 72 to prevent, reduce, and/or control leakage of secondary airflow S through gap 188 into core airflow path C. Seal 102 may form a partial seal or a complete seal between ROP segment 280 and stator vane 72, thereby reducing or eliminating leakage airflow L. Seal 102 may include a plurality of annular seals, as described herein, and may be placed between ROP segment 280 and stator vane 72 to limit leakage of secondary airflow S between ROP segment 280 and stator vane 72 and into core airflow path C.
In various embodiments, with reference to
Referring to
BOAS assembly 10 may comprise a ROP segment 280 coupled with and disposed between a plurality of adjacent ROP segment 280. With reference to
In various embodiments, a plurality of ROP segment 280 may be arranged in BOAS assembly 10 in a variety of configurations. In various embodiments, with reference to
In various embodiments, and with reference to
Benefits and other advantages have been described herein with regard to specific embodiments. Furthermore, the connecting lines shown in the various figures contained herein are intended to represent exemplary functional relationships and/or physical couplings between the various elements. It should be noted that many alternative or additional functional relationships or physical connections may be present in a practical system. However, the benefits, advantages, and any elements that may cause any benefit or advantage to occur or become more pronounced are not to be construed as critical, required, or essential features or elements of the disclosure. The scope of the disclosure is accordingly to be limited by nothing other than the appended claims, in which reference to an element in the singular is not intended to mean “one and only one” unless explicitly so stated, but rather “one or more.” Moreover, where a phrase similar to “at least one of A, B, or C” is used in the claims, it is intended that the phrase be interpreted to mean that A alone may be present in an embodiment, B alone may be present in an embodiment, C alone may be present in an embodiment, or that any combination of the elements A, B and C may be present in a single embodiment; for example, A and B, A and C, B and C, or A and B and C.
Systems, methods and apparatus are provided herein. In the detailed description herein, references to “various embodiments”, “one embodiment”, “an embodiment”, “an example embodiment”, etc., indicate that the embodiment described may include a particular feature, structure, or characteristic, but every embodiment may not necessarily include the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the art to affect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described. After reading the description, it will be apparent to one skilled in the relevant art(s) how to implement the disclosure in alternative embodiments.
Furthermore, no element, component, or method step in the present disclosure is intended to be dedicated to the public regardless of whether the element, component, or method step is explicitly recited in the claims. No claim element is intended to invoke 35 U.S.C. 112(f) unless the element is expressly recited using the phrase “means for.” As used herein, the terms “comprises,” “comprising,” or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.
This invention was made with Government support awarded by the United States. The Government has certain rights in this invention.
