Cross fire tube retention system

A system for retaining a cross fire tube in a multi-combustor gas turbine engine is disclosed. The system comprises a flow sleeve having a generally annular body, and a flange at a forward end thereof and having one or more recessed portions. A cross fire tube extends through one or more openings in the flow sleeve and is secured in place by a retention clip. The retention clip includes a plurality of fingers which engage the cross fire tube and a mounting plate engaging the one or more recessed portions of the flow sleeve flange so as to create a clip engagement having a lower profile than prior art configurations.

CROSS-REFERENCE TO RELATED APPLICATIONS

Not applicable.

Not applicable.

TECHNICAL FIELD

This present disclosure relates generally to a system for retaining a cross fire tube in a gas turbine combustor. More specifically, embodiments of the present disclosure relate to a flow sleeve and retention clip used to secure a cross fire tube in proper axial and radial position while also reducing blockage to a surrounding air passageway.

BACKGROUND OF THE DISCLOSURE

A gas turbine engine typically comprises a multi-stage compressor coupled to a multi-stage turbine via an axial shaft. Air enters the gas turbine engine and passes through the compressor where its temperature and pressure increase as it passes through subsequent stages of the compressor. The compressed air is then directed to one or more combustors where it mixes with a fuel source to create a combustible mixture. This mixture is ignited in the one or more combustors to create a flow of hot combustion gases. These gases are directed into the turbine causing the turbine to rotate, thereby driving the compressor. The output of the gas turbine engine can be mechanical thrust via exhaust from the turbine or shaft power from the rotation of an axial shaft, where the axial shaft can drive a generator to produce electricity.

In a typical industrial gas turbine engine, the combustor section comprises a plurality of can-annular combustors. In this configuration, a plurality of individual combustors is arranged about the axis of the gas turbine engine, where each combustor receives a portion of the compressed air from the compressor. However, in order to eliminate the need for ignition sources in each combustor for use at start-up as well as any time a combustor flashes back or when a flame is unintentionally extinguished, the plurality of individual combustors is connected by a plurality of cross fire tubes. In operation, one combustor can be ignited, and the flame will pass through the cross fire tubes to an adjacent combustor, thereby igniting a combustible mixture in an adjacent combustor.

A cross fire tube arrangement in accordance with the prior art is disclosed inFIGS. 1-4. Referring initially toFIG. 1, a flow sleeve100is shown and includes a plurality of openings102in the wall of the flow sleeve. The flow sleeve100also includes a plurality of lugs104, which are used for positioning a combustion liner within the flow sleeve100. Also located within the flow sleeve100are a plurality of brackets106, which are more clearly depicted inFIG. 2. The cross fire tubes108are placed through the openings102and brackets106, as shown inFIG. 3.

Referring now toFIG. 4, the cross fire tubes108are secured in the flow sleeve/liner by a clip110. The clip110includes a hook portion112which can be used to help install and remove the clip110from the flow sleeve100. As a result of the configuration of the bracket106and clip110, each of these features extend inward and into a flow path between the flow sleeve100and combustion liner (not shown), thus interfering and restricting the flow of air passing between the flow sleeve100and a combustion liner. In a common configuration, the bracket106and clip110extend over half an inch into the flow path of the passing airflow thus adversely impacting air flow to a combustor and combustion dynamics and emissions.

BRIEF SUMMARY OF THE DISCLOSURE

The following presents a simplified summary of the disclosure to provide a basic understanding of some aspects thereof. This summary is not an extensive overview of the application. It is not intended to identify critical elements of the disclosure or to delineate the scope of the disclosure. Its sole purpose is to present some concepts of the disclosure in a simplified form as a prelude to the more detailed description that is presented elsewhere herein.

The present disclosure provides a system for retaining a cross fire tube within a gas turbine combustor, including a flow sleeve and retention clip configuration reducing potential blockage to an air passageway between the flow sleeve and a combustion liner.

In an embodiment of the present disclosure, a flow sleeve for a gas turbine combustion system is provided. The flow sleeve comprises a generally annular body having a flange at a forward end thereof and one or more openings in the generally annular body for receiving one or more cross fire tubes from an adjacent combustion chamber. The flow sleeve further comprises one or more recessed portions in the flange and a clip block having a T-shaped cross section positioned axially between the one or more recessed portions and the one or more openings.

In an alternate embodiment of the present disclosure, a system for retaining a cross fire tube between adjacent combustors in a gas turbine engine is disclosed. The system comprises a flow sleeve having a generally annular body, a flange at a forward end of the generally annular body, where the flange has one or more recessed portions. The generally annular body has one or more openings and a clip block having a T-shaped cross section positioned axially between the one or more recessed portions and the one or more openings. A cross fire tube extends through each of the one or more openings and is secured by a retention clip which extends along an inner surface of the generally annular body and has a mounting plate engaging the one or more recessed portions of the flow sleeve flange. A centerbody extends from the mounting plate and a first finger and a second finger extend from the center body, where the first and second fingers surround a portion of the tube, thus preventing the tube from moving into or out of the one or more openings in the generally annular body.

In yet another embodiment of the present disclosure, a retention clip for securing a cross fire tube in a gas turbine combustor is provided. The retention clip comprises a mounting plate, a centerbody extending from the mounting plate where the centerbody has a through hole and a slot extending away from the through hole. A first finger and a second finger extend from the center body, where the first and second fingers have an axially extending space therebetween. The retention clip has at least one curved portion extending along the centerbody such that the first and second fingers provide a spring tension when the clip is secured to the flow sleeve.

The present disclosure is aimed at providing an improved way of securing cross fire tubes between adjacent combustors while also reducing any interference into the surrounding passageway. These and other features of this disclosure can be best understood from the following description and claims.

DETAILED DESCRIPTION

The present disclosure is intended for use in a gas turbine engine, such as a gas turbine used for aircraft engines and/or power generation. As such, the present disclosure is capable of being used in a variety of turbine operating environments, regardless of the manufacturer.

As those skilled in the art will readily appreciate, a gas turbine engine is circumferentially disposed about an engine centerline, or axial centerline axis. The engine includes a compressor, a combustion section and a turbine with the turbine coupled to the compressor via an engine shaft. As is well known in the art, air compressed in the compressor is mixed with fuel and ignited in the combustion section and then expanded in the turbine. For certain gas turbine engines, such as industrial gas turbines used in power generation, the combustion system comprises a plurality of interconnected can-annular combustion chambers. The chambers are connected by a plurality of tubes for passing a flame between adjacent combustors to aid in the ignition process.

The present disclosure is depicted inFIGS. 5-8. Referring initially toFIG. 5, a flow sleeve500for use in a gas turbine combustion system is shown. The flow sleeve500comprises a generally annular body502having a flange504at a forward end506of the generally annular body502. The flow sleeve500also includes one or more openings508spaced about the generally annular body502. These one or more openings508are preferably two openings, as shown inFIG. 5, and are used for communicating with combustors adjacent to the flow sleeve500. This communication occurs via a plurality of cross fire tubes which serve as a conduit in which a flame can be passed from one combustor to an adjacent combustor.

Referring now toFIGS. 5 and 6, the flange504of flow sleeve500further comprises one or more recessed portions510. The one or more recessed portions510correspond directly to the one or more openings508in the generally annular body502. Thus, for the embodiment of the present disclosure shown inFIG. 5, the flow sleeve500includes two recessed portions510in the flange504. Within the recessed portions510is a plurality of holes512which provide a way of securing a retainer clip, as will be discussed in more detail below. The plurality of holes512can be through holes or threaded.

The flow sleeve500also comprises a clip block514positioned axially between the one or more recessed portions510and the one or more openings508. The clip block514, which in one embodiment is welded to the generally annular body502, is used to secure a retainer clip and cross fire tube in place, as discussed in more detail below. The clip block514can be formed of a variety of shapes depending on the specific cross fire tube and retainer clip geometry. For the embodiment depicted inFIGS. 5-8, the clip block514has a T-shaped cross section. In an embodiment, the clip block514has a first leg515A and a second leg515B generally perpendicular thereto. When the clip block514is secured (e.g., welded) to the generally annular body502, a gap517A may be formed between the annular body502and the first leg515A at one side of the second leg515B, and a gap517B may be formed between the annular body502and the first leg515A at an opposing side of the second leg515B.

As discussed above, in a can-annular combustor configuration, a combustion liner is located within a flow sleeve. Compressed air from an engine compressor is directed between the combustion liner and flow sleeve in order to cool the combustion liner and direct the air into the combustion liner. As a result, this air is also preheated before entering the combustion liner and undergoes a combustion process to generate hot combustion gases for powering the turbine section. In order to properly locate the combustion liner within the flow sleeve, a plurality of pegs516extend radially inward from the generally annular body502. Mounting tabs extend radially outward from a combustion liner and slide into the slots in the plurality of pegs516.

Another feature of the present disclosure is shown inFIG. 7. A retention clip700is provided for securing a cross fire tube in a gas turbine combustor. The retention clip700comprises a mounting plate702having one or more mounting holes703located therein and a centerbody704extending from the mounting plate702. As can be seen inFIG. 7, the mounting plate702is generally perpendicular to the centerbody704. The centerbody704has a through hole706and a slot708extending away from the through hole706. Extending away from the centerbody704are two fingers, a first finger710and a second finger712. The first finger710is separated from the second finger712by an axially extending space714. The axially extending space714, the slot708, and the through hole706permit the first and second fingers710and712to expand in opposing directions in multiple planes, such that the fingers can expand to surround another component positioned in the axially extending space714.

Referring still toFIG. 7, another feature of the retention clip700is at least one curved portion, or bend,716that extends along a portion of the centerbody704and/or the first and second fingers710and712. The at least one curved portion716shown inFIG. 7comprises two portions curved in opposing directions. In the embodiment depicted, the at least one curved portion is located along the centerbody704between the through hole706and the first and second fingers710and712. Furthermore, one curved portion716curves in a direction towards the mounting plate702while the adjacent curved portion716curves away from the mounting plate702. This set of opposing curve portions creates a spring effect in the clip700when the clip700is placed against adjacent mating surfaces, such as the annular body502of flow sleeve500.

The retainer clip can be made from a variety of materials but is preferably made in a flat pattern from a material capable of withstanding the temperatures adjacent the cross fire tubes as well as the adjacent components. Such acceptable materials may include a tool steel as well as Inconel® X-750, a nickel-chromium alloy. The retainer clip700can be cut from a plate, typically 0.062 inches to 0.125 inches thick. Features such as the through hole706, slot708, and axially extending space714are cut out of the plate material while in a flat pattern, typically by a laser or wire EDM and then the mounting flange702is bent at approximately 90-degree angle relative to the centerbody704.

Referring now toFIG. 8, a system800for retaining a cross fire tube in a gas turbine engine having multiple combustors is disclosed. The system800utilizes the features discussed above with respect toFIGS. 5-7. As such, the terminology used to describe the system800and its assembly process will incorporate terms and reference identifiers discussed above.

The system800comprises a flow sleeve500having a generally annular body502, a flange504with one or more recessed portions510located therein. The generally annular body502of the flow sleeve500also includes one or more openings508as well as a clip block514positioned between the one or more recessed portions510and the one or more openings508.

A tube802extends through the one or more openings508of the flow sleeve500. This tube, also known as a cross fire tube may comprise multiple tubes, often in a telescoping arrangement for connecting adjacent combustors. The tube802may also include a groove about its outer surface804for receiving the retention clip700. As shown inFIG. 8, the retention clip700extends along an inner surface806of the generally annular body502with the mounting plate702engaging the recessed portion510in the flange504. The centerbody704of the retention clip700extends from the mounting plate702and to the first finger710and the second finger712, each of which surround a portion of the tube802, thus preventing the tube802from moving into or out of the one or more openings508in the generally annular body502.

In operation, once a flow sleeve is installed in adjacent combustor cases, one or more tubes802, also commonly referred to as cross fire tubes, are passed through the openings508in the flow sleeve annular body502. Then, a combustion liner is installed into the flow sleeve500. Once the combustion liner is positioned within the flow sleeve500, the tubes802are slid into the corresponding combustion liner. Once the tubes802are in the appropriate position through the flow sleeve and into the combustion liner, the retention clip700is positioned between the inner surface806of the generally annular body502and the clip block514, such that each of the first finger710and second finger712extends at least partially through one of the gaps517A and517B and the fingers710,712expand to surround at least a portion of the tube802. The retention clip is slid into the flow sleeve500until the mounting plate702is positioned within the recessed portion510of the flange504. Then, the mounting plate is secured to the flange504by placing a plurality of fasteners (not depicted) through mounting holes703in the mounting plate702and into the holes512in the recessed portion510of the flange504.

Due to the curvatures716in the retention clip700, and as discussed above, the retention clip700provides some resistance as it is positioned in place between the inner surface806of the generally annular body502and the clip block514. This further aids in preventing accidental removal of the retention clip700.

As can be seen fromFIG. 8, the clip block514and retention clip700are positioned closer to the inner surface806of the generally annular body502than in prior art configurations. More specifically, the retention clip700of the present disclosure extends radially into the flow sleeve500, and thus the airflow between the flow sleeve and combustion liner, by approximately 0.27 inches. The prior art configuration, as depicted inFIGS. 1-4, extends into the flow sleeve more than twice as much, or upwards of 0.56 inches, thereby creating a much larger blockage than the present disclosure. As one skilled in the art will appreciate, a blockage in compressed air can limit the air flow to the combustor, thus adversely impacting combustor emissions and impacting combustion dynamics.

Although a preferred embodiment of this disclosure has been provided, one of ordinary skill in this art would recognize that certain modifications would come within the scope of this disclosure. For that reason, the following claims should be studied to determine the true scope and content of this disclosure. Since many possible embodiments may be made of the disclosure without departing from the scope thereof, it is to be understood that all matter herein set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.

From the foregoing, it will be seen that this disclosure is one well adapted to attain all the ends and objects hereinabove set forth together with other advantages which are obvious, and which are inherent to the structure.