Abstract:
The present invention are directed towards a system and method for providing a way of reducing the vibrations and wear between mating components of a gas turbine combustor. The gas turbine combustor includes a flow sleeve having a plurality of liner stops and a combustion liner located radially within the flow sleeve. Spring dampers are positioned between the combustion liner and the flow sleeve to restrict the relative movement between the flow sleeve and the combustion liner and dampen vibrations at their assembly location. The spring dampers are capable of compressing to permit thermal growth between the combustion liner and flow sleeve.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     Not applicable. 
     TECHNICAL FIELD 
     The present invention relates to gas turbine engines. More particularly, embodiments of the present invention relate to an apparatus and method for damping vibrations that occur in a gas turbine combustor. 
     BACKGROUND OF THE INVENTION 
     Gas turbine engines operate to produce mechanical work or thrust. One type of gas turbine engine is a land-based engine that has a generator coupled thereto which harnesses the mechanical work for the purposes of generating electricity. A gas turbine engine typically comprises at least a compressor section having a series of rotating compressor blades, one or more combustors, and a turbine section. Air enters the engine through an inlet and then passes through the compressor, where the rotating blades compress the air and raise its pressure. 
     The compressed air flows from the compressor and towards the combustion section. For an individual combustor, a flow sleeve envelops a combustion liner, as shown in  FIG. 1 , directs the air along the combustion liner until the air is injected into the liner. The flow sleeve also serves to help position the liner within the combustor. However, the interface between these two components of the combustion system can give rise to excessive vibrations and wear due to gaps that exist in the assembly between the combustion liner to the flow sleeve. The gaps are necessary to provide for ease of assembly of the combustion parts. 
     The compressed air, which is directed into one or more combustors is mixed with fuel and the mixture is ignited. The hot combustion gases are then directed from the combustion section to a turbine section by a transition duct. 
     SUMMARY 
     Embodiments of the present invention are directed towards a system and method for, among other things, providing a way of reducing the vibrations and relative motion between mating components of a gas turbine combustor. The present invention provides an embodiment directed towards a gas turbine combustor comprising a flow sleeve having a plurality of liner stops and a combustion liner located radially within the flow sleeve. One or more spring dampers are positioned between the combustion liner and the flow sleeve. The spring dampers are configured so as to permit compression. This compression occurs primarily as the combustion liner moves radially outward towards the flow sleeve during operation at elevated temperatures. The spring damper maintains contact with both the flow sleeve and the combustion liner so as to dampen the vibrations between the mating components. 
     The present invention also provides a spring damper for use in a gas turbine combustor. The spring damper has a generally corrugated body with an inner radial wall portion connected to an outer radial wall portion by a pair of radially extending sidewalls. Located in the inner and outer radial wall portions is a plurality of generally U-shaped portions. The spring damper also includes a retention mechanism that extends generally parallel in an axial direction to the inner radial wall portion. The spring damper includes a retention mechanism for attaching to the combustion liner or the flow sleeve to restrict movement in at least the axial direction. 
     The present invention also comprises a method of reducing vibrations between a combustion liner and a flow sleeve in a gas turbine combustor. A combustion liner is inserted radially within a flow sleeve and once located in the desired axial position, one or more spring dampers are compressed, so as to reduce their radial height. The one or more spring dampers are compressed by pressing portions of the inner radial wall and the outer radial wall towards each other. The compressed spring dampers are placed radially between the combustion liner and the flow sleeve and then released from the compressed state. As a result, the spring damper applies a pressure load to the combustion liner and the flow sleeve which serves to dampen vibrations that occur between the combustion liner and flow sleeve. 
     Additional advantages and features of the present invention will be set forth in part in a description which follows, and in part will become apparent to those skilled in the art upon examination of the following, or may be learned from practice of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
       The present invention is described in detail below with reference to the attached drawing figures, wherein: 
         FIG. 1  depicts a partial end view of a portion of a combustion liner installed in a flow sleeve in accordance with a prior art configuration; 
         FIG. 2  depicts a perspective view in accordance with an embodiment of the present invention; 
         FIG. 3  depicts an end view in accordance with an embodiment of the present invention; 
         FIG. 4  depicts a partial end view of a combustion liner installed in a flow sleeve in accordance with an embodiment of the present invention; 
         FIG. 5  depicts a partial perspective view of a combustion liner installed in a flow sleeve with a spring damper in accordance with an embodiment of the present invention; 
         FIG. 6  depicts a perspective view of a spring damper in accordance with an embodiment of the present invention; 
         FIG. 7  depicts an alternate perspective view of a spring damper in accordance with an embodiment of the present invention; and, 
         FIG. 8  depicts yet another alternate perspective view of a spring damper in accordance with an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     The subject matter of the present invention is described with specificity herein to meet statutory requirements. However, the description itself is not intended to limit the scope of this patent. Rather, the inventors have contemplated that the claimed subject matter might also be embodied in other ways, to include different components, combinations of components, steps, or combinations of steps similar to the ones described in this document, in conjunction with other present or future technologies. 
     The present invention will now be described with reference to the accompanying  FIGS. 2-8 . Referring initially to  FIGS. 2 and 3 , a gas turbine combustor  100  is shown having a flow sleeve  102  and a combustion liner  104 . The flow sleeve  102  has a sleeve wall  106  with a first diameter D 1 , and a plurality of liner stops  108  that extend radially inward from the sleeve wall  106 . 
     The combustion liner  104  comprises a generally annular liner wall  110  having a second diameter D 2  that is smaller than first diameter D 1  such that the combustion liner  104  is located radially within the flow sleeve  102 . However, the combustion liner  104  also has an inlet end  112  with one or more openings  114  and an outlet end  116  located generally opposite of the inlet end  112 . The one or more openings  114  are sized to receive one or more fuel injectors. 
     Referring to  FIG. 4 , the combustion liner  104  also comprises a retention device  118  located adjacent to an inlet end  112 . The retention device  118  can take on a number of forms, but is intended to at least secure one or more spring dampers  122  in place, as will be discussed in more detail below. For an embodiment of the present invention, the retention device  118  can be a series of pins located about the perimeter of the generally annular wall  110  adjacent to the inlet end  106 . 
     Extending radially outward from the generally annular liner wall  110  is a plurality of locating tabs  120 . These locating tabs are used to secure the combustion liner  104  in at least an axial and circumferential location in the flow sleeve  102 . More specifically, the locating tabs  120  slide into slots in the liner stops  108  that correspond generally to the shape of the locating tabs  120 , but have dimensions slightly larger than the locating tabs  120 . It should be understood that the terms “axial”, “radial”, and “circumferential”, as used herein, generally are provided with reference to a theoretical turbine in which the combustor  100  is installed. Accordingly, “axial” generally means with reference to an axis identical to (or parallel with) an axis of the turbine, “radial” generally means along a radius extending from a center rotational axis of the turbine, and “circumferential” generally means along a circumference of a circular frame of the turbine. Further, the terms “fastener”, “bolt”, and “pin” are used interchangeably herein to denote a component for mechanically coupling adjacent structures together (e.g., through a threaded interconnection, an interference fit, etc). 
     The combustor  100  also includes one or more spring dampers  122 . An embodiment of the spring damper for the present invention is shown in detail in  FIGS. 6-8  and can be installed in the gas turbine combustor  100  as shown in  FIGS. 2-5 . The spring damper  122  is positioned radially between the flow sleeve  102  and the combustion liner  104  such that a portion of the spring damper maintains contact with the flow sleeve  102  and another portion of the spring damper maintains contact with the combustion liner  104 . The spring damper  122  also includes a means for engaging the retention device  118 . A variety of means can be used for engaging the retention device  118  and will depend on the type of retention device  118  used. For an embodiment of the present invention depicted in the FIGS., a representative means includes a retention plate  138  having openings  126  sized slightly larger than the pins of the retention device  118 . This allows the spring damper  122  to be secured in place. 
     The spring damper  122 , which is shown in more detail in  FIGS. 6-8 , comprises a generally corrugated body  128  having a thickness T and an axial length L. The spring damper  122  has an inner radial wall portion  130  connected to an outer radial wall portion  132  by a pair of radially extending sidewalls  134 . The inner and outer radial wall portions,  130  and  132 , provide increased surface contact area of the spring damper  122  to the combustion liner  104  and flow sleeve  102  and contains a plurality of generally U-shaped portions  136 , whereas the radially extending sidewalls  134  do not have any generally U-shaped portions. The generally U-shaped portions  136  in the inner radial wall portion  130  oppose and are spaced a distance apart from the generally U-shaped portions  136  in the outer radial wall portion  132 . This is but one general form of a spring damper and the size of the damper and overall shape of the corrugated body can vary depending on the application. 
     Extending generally parallel to the inner radial wall portion  130  is a clip portion, or retention plate  138 . The retention plate  138  can be integral with the spring damper  122  or a separate component as shown in  FIGS. 6-8 . As shown in  FIG. 8 , the retention plate  138  has an opening  140  that engages a pin  142  of the corrugated body  128 . The retention plate  138  is also formed in a way so as to apply a pre-load of the retention plate  138  and the inner radial wall portion  130  against the combustion liner  104 . 
     The retention plate  138  is configured so as to aid in locating and securing the spring damper within the gas turbine combustor. In addition to the openings  126 , the retention plate  138  also has an edge  144  used for securing the spring damper  122  in an axial direction. This locating means will be discussed in more detail below. 
     In operation, a cooling fluid such as compressed air flows between the combustion liner  104  and the flow sleeve  102  and towards the inlet end  106 . The cooling fluid cools the generally annular liner wall  110  of the combustion liner  104  before entering the combustion liner  104 , where it mixes with fuel and ignites to form hot combustion gases used to drive the turbine section of an engine. Since the combustion liner is operating at extremely high temperatures the material of the liner will tend to grow radially outward due to thermal expansion. While the spring dampers are designed to reduce vibrations in and around the liner stops of the flow sleeve  102 , the dampers do not inhibit the thermal growth of the combustion liner  104  relative to the flow sleeve  102 . 
     Through the use of one or more spring dampers  122 , vibrations between a combustion liner  104  and a flow sleeve  102  are reduced. As previously discussed, the combustion liner  104  is inserted radially within the flow sleeve  102  and positioned such that the plurality of locating tabs  120  are positioned within the plurality of liner stops  108  of the flow sleeve  102 . Due to manufacturing and assembly tolerances, there are gaps between the locating tabs  120  and the liner stops  108 . During operation, the gaps permit the combustion liner and flow sleeve to move relative to each other at this interface as well as to move relative to other associated combustion components such as cross fire tubes. 
     The one or more spring dampers  122 , in the compressed state, is then placed radially between the combustion liner  104  and the flow sleeve  102 . The compressed damper is placed at an axial location where the openings  126  in the retention plate  138  are secured to the retention device  118 . This interface coincides with where the edge  144  is located adjacent to the inlet  106  of the combustion liner  104  (see  FIG. 5 ). The location of the edge  144  and openings  126  of the retention plate  138  provide for axial and circumferential restraint of the spring damper  122 . The compressed spring damper is then released, allowing the inner radial wall portion  130  to contact and apply a pressure load to the combustion liner  104  and outer radial wall portion  132  to contact an apply a pressure load to the flow sleeve  102 . During operation, the combustion liner expands radially and portions of the inner radial wall  130  and outer radial wall  132  are compressed, which reduces the radial height H of the spring damper  122 . The spring damper  122  is configured through its corrugated shape and generally U-shaped portions  136  to impart a pre-load in the radial direction. 
     The present invention has been described in relation to particular embodiments, which are intended in all respects to be illustrative rather than restrictive. Alternative embodiments will become apparent to those of ordinary skill in the art to which the present invention pertains without departing from its scope. 
     From the foregoing, it will be seen that this invention is one well adapted to attain all the ends and objects set forth above, together with other advantages which are obvious and inherent to the system and method. It will be understood that certain features and sub-combinations are of utility and may be employed without reference to other features and sub-combinations. This is contemplated by and within the scope of the claims.