Abstract:
A hanger includes a connector assembly for coupling the hanger to a first annular duct, a bracket for coupling the hanger to a second annular duct concentrically disposed within the first annular duct, and a cable formed by a plurality of wires bound together that extend from the connector assembly to the bracket. A plurality of circumferentially-spaced hangers placed in tension support an exhaust duct liner relative to an exhaust duct. The hangers permit circumferential and axial displacement at each hanger of the exhaust duct liner relative to the exhaust duct. The displacement of the exhaust duct liner relative to the exhaust duct at each hanger is permitted in a first radial direction that decreases tension in the cable and is restrained in a second radial direction that increases tension in the cable.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This is a continuation of U.S. patent application Ser. No. 13/586,623, filed Aug. 15, 2012. 
     
    
     BACKGROUND 
       [0002]    This invention relates generally to gas turbine engines and more particularly to exhaust duct liner attachment systems and methods. In gas turbine engines, it is necessary to protect exhaust ducts with an insulating shield in order to prevent heated core gases from damaging the exhaust ducts. Typically, exhaust ducts are made from titanium-based alloys and have temperature limits of approximately 300° F.-800° F. (˜148.9° C.-426.7° C.). Exhaust gases, however, may reach much higher temperatures, particularly if thrust augmentation is conducted. It is, therefore, necessary to line exhaust ducts with a material that is capable of withstanding the peak temperatures of the core gases and that prevents the exhaust duct from reaching its temperature limitations. Exhaust duct liners are typically made from nickel-based alloys, which have temperature limits of approximately 700° F.-1200° F. (˜371.1° C.-648.9° C.). In order to alleviate some of the heat from the exhaust gases imparted to the liner, cooling air is passed between the exhaust duct and liner and is bled through thousands of small cooling holes in the liner. For example, bypass air is routed between the duct and liner in turbofan engines. Thus, the exhaust duct and liner are subjected to different pressure and temperature gradients, which results in differing deflections and expansions of each body. 
         [0003]    In order to maintain the desired temperature and pressure profile along the exhaust duct and liner, it is desirable to maintain proper spacing between the exhaust duct and liner. The differing pressures, temperatures and functional requirements of the exhaust duct, however, produce three-dimensional forces between the duct and liner, which tend to shift the liner out of alignment. Various designs have been put forth to maintain proper alignment, such as described in U.S. Pat. Nos. 7,581,399 and 7,861,535, which are assigned to United Technologies Corporation. Some of these designs, however, require careful insertion of support members through holes in either the exhaust duct or liner. There is, therefore, a need for an easy to install exhaust duct liner suspension system that maintains proper spacing between an exhaust duct and a duct liner, while also permitting the liner to shift in other directions to accommodate, among other things, thermal growth. 
       SUMMARY 
       [0004]    A hanger comprises a connector assembly, a bracket, and a cable. The connector assembly is configured to be coupled to a first annular duct. The bracket is configured to be coupled to a second annular duct concentrically disposed within the first annular duct. The cable is formed by a plurality of wires bound together that extend from the connector assembly to the bracket. The cable is placed in tension to support the second annular duct relative to the first annular duct. 
         [0005]    A plurality of circumferentially-spaced hangers for use in a gas turbine engine exhaust system, each hanger comprising a connector assembly for connecting to an exhaust duct of the gas turbine engine, a bracket for connecting to an exhaust duct line of the gas turbine exhaust system, and a cable extending from the connector assembly to the bracket. The cable is placed in tension to support the exhaust duct line relative to the exhaust duct. The displacement of the exhaust duct liner relative to the exhaust duct is permitted at each hanger in a first radial direction that decreases tension in the cable and is restrained in a second radial direction that increases tension in the cable. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]      FIG. 1  is a schematic diagram of a dual-spool, low-bypass ratio turbofan engine having an exhaust duct liner supported within an exhaust duct using hangers having adjustable cable assemblies of the present invention. 
           [0007]      FIG. 2  is a side view of the adjustable cable assembly of the present invention having a connector assembly connecting to a cut-away portion of an exhaust duct and a rotating joint connected to a cut-away portion of an exhaust duct liner. 
           [0008]      FIG. 3  is a top view of the connector assembly of  FIG. 2  showing an interface between an oblong slot in the exhaust duct and an oblong spacer on the connector assembly. 
           [0009]      FIG. 4A  is a top view of the rotating joint of  FIG. 2  showing a ball engaging a retention slot in a housing. 
           [0010]      FIG. 4B  is a side view of the rotating joint of  FIG. 2  showing a ball inserted into an access opening in the housing. 
           [0011]      FIG. 5  is a close-up of callout A of  FIG. 2  showing a cross-sectional view of a collar used to connect a cable to the connector assembly and the rotating joint. 
       
    
    
     DETAILED DESCRIPTION 
       [0012]      FIG. 1  shows a schematic diagram of dual-spool, low-bypass ratio turbofan engine  10 , in which hangers  12  of the present invention can be used. Although, in other embodiments, the present invention is applicable to other types of gas turbine engines such as high-bypass ratio turbofans including turbofans using fan drive gear systems. Turbofan engine  10  also includes fan duct  14 , drive fan  15  (including stages  16   a - 16   c ), low pressure compressor  17 , high pressure compressor  18 , combustor  20 , high pressure turbine  22 , low pressure turbine  24  and exhaust system  26 . Drive fan  15  and low pressure compressor  17  are driven by low pressure turbine  24  with shaft  27 . High pressure compressor  18  is driven by high pressure turbine  22  with shaft  28 . High pressure compressor  18 , combustor  20 , high pressure turbine  22  and shaft  28  comprise the core of turbofan engine  10 , which produces the high energy air stream that is ultimately used to drive low pressure turbine  24  and provide high pressure flow to produce thrust via both primary air A P  and secondary air A S . Exhaust system  26  includes exhaust duct  30 , liner  32 , augmentation system  34  and exhaust nozzle  36 . Exhaust system  26  also includes hangers  12 , which include adjustable cable assemblies of the present invention. Hangers  12  are disposed in multiple circumferential arrays to maintain liner  32  mounted within exhaust duct  30 .  FIG. 1  shows three, axial sequential arrays of hangers  12 . However, liner  32  may be supported by many more arrays wherein the total number of hangers numbers in the hundreds. 
         [0013]    Ambient air A Ambient  enters engine  10  at inlet  38  through drive fan  15 . Drive fan  15  is rotated by low pressure turbine  24  to accelerate ambient air A Ambient  thereby producing a major portion of the thrust output of engine  10 . Accelerated ambient air A Ambient  is divided into two streams of air: primary air A P  and secondary air A S . Secondary air A S , also known as bypass air, passes through fan exit guide vanes  39  and between fan duct  14  and aft duct  40  where it passes on to exhaust system  26 . Thus, the principal function of secondary air A S  is the production of thrust from drive fan  15 . Secondary air A S  also serves to cool exhaust duct liner  32  from primary air A P . Primary air A P , also known as hot air, is a stream of air that is directed first into low pressure compressor  17  and then into high pressure compressor  18  within engine case  42 . Pressurized primary air A P  is then passed into combustor  20  where it is mixed with a fuel supply and ignited to produce high energy gases, as is known in the art. The high energy gasses are used to turn high pressure turbine  22  and low pressure turbine  24 . Turbine  22  drives compressor  18  with shaft  28 , while turbine  24  drives compressor  17  and drive fan  15  with shaft  27 . Primary air A P  passes from engine case  42  to exhaust system  26  through exit guide vanes  44 . 
         [0014]    Mixed combusted primary air A P  and bypassed secondary air A S  are passed into exhaust duct  30  of exhaust system  26 . As is known in the art, a secondary combustion process can be carried out using augmentation system  34  within liner  32 . The augmentation process elevates the speed and temperature of the mixed exhaust gas to further produce thrust using exhaust nozzle  36 . Liner  32 , which is suspended from exhaust duct  30  with hangers  12 , prevents overheating of duct  30  from the secondary combustion process. Hangers  12  allow liner  32  to shift within exhaust duct  30  to accommodate different thermal expansion rates between liner  32  and duct  30 , while accommodating different temperature gradients throughout exhaust system  26 . Hangers  12  incorporate adjustable cable assemblies that permit radial, circumferential and axial displacement of liner  32  within duct  30  without inducing additional stress. The adjustable cable assemblies of hangers  12  also facilitate expedient assembly of liner  32  within exhaust duct  30 . 
         [0015]      FIG. 2  is a partial cross-sectional side view of adjustable cable assembly  46  of the present invention having connector assembly  48  connecting to a cut-away portion of exhaust duct  30  and rotating joint  50  connected to a cut-away portion of exhaust duct liner  32 . Adjustable cable assembly  46  includes cable  52 , which connects connector assembly  48  with rotating joint  50 . Connector assembly  48  includes shaft  54 , oblong spacer  56 , washer  58  and nut  60 . Shaft  54  includes wrenching feature  62 , and oblong spacer  56  includes flange  64 . Rotating joint  50  includes ball  66 , collar  68  and housing  70 . Housing  70  includes sidewall  72 , end wall  74 , retention slot  76  and access opening  78 . 
         [0016]    Oblong spacer  56  of connector assembly  48  is positioned into oblong slot  80  in exhaust duct  30 . Flange  64  is positioned inside exhaust duct  30  and has an outer edge that is wider (with reference to  FIG. 2 ) than oblong slot  80 . Specifically, flange  64  is longer than oblong spacer  56  in the longer direction of oblong spacer  56 , as shown in  FIG. 3 . O-ring  81  is positioned around oblong spacer  56  adjacent flange  64 . In one embodiment, flange  64  and oblong spacer  56  are made from a single piece by any suitable manufacturing method. In other embodiments, flange  64  comprises a plate or ring welded to oblong spacer  56 . O-ring  81  may have a circular cross-sectional profile or an L-shaped cross-sectional profile as shown in  FIG. 2 . Shaft  54  is threaded into threaded bore  82  in oblong spacer  56  such that wrenching feature  62  extends to the exterior of exhaust duct  30 . Bore  84  in washer  58  is positioned around shaft  54  and nut  60  is threaded onto shaft  54 . Shaft  54  is, therefore, long enough to extend through flange  64 , oblong spacer  56 , washer  58  and nut  60 , while also accommodating collar  85  for attachment with cable  52 . 
         [0017]    Ball  66  of rotating joint  50  is connected to housing  70  at exhaust duct liner  32 . Specifically, ball  66  is inserted into opening  78  so as to be disposed between liner  32  and end wall  74 . Opening  78  is wider and taller than ball  66  so as to permit entry of ball  66  into housing  70 . Collar  68  extends from ball  66  so as to extend through slot  76 . Slot  76  is wider than collar  68 , but narrower than ball  66  so as to prevent ball  66  from passing through slot  76 . Cable  52  is inserted into and coupled with sockets inside collar  68  and collar  85  to join connector assembly  48  with rotating joint  50 , thereby tethering exhaust duct liner  32  to exhaust duct  30 . 
         [0018]    The radial position of shaft  54  with respect to housing  70  can be adjusted by rotating wrenching feature  62 . Wrenching feature  62  comprises a hex head in the embodiment shown, but may comprise other torque transmitting features such as a pair of slab sides. In particular, shaft  54  is backed out of bore  82  to bring ball  66  into engagement with end wall  74  and slot  76  thereby putting cable  52  into tension. Nut  60  is tightened down on shaft  54  against washer  58  to immobilize shaft  54  with respect to oblong spacer  56  after shaft  54  is adjusted to the desired position. Nut  60  may comprise a conventional nut or a self-locking nut. Housing  70  can be shaped, as will be discussed with reference to  FIGS. 4A and 4B , so as to permit secure, rotational engagement with ball  66  when cable  52  is in tension. 
         [0019]      FIG. 3  is a top view of connector assembly  48  of  FIG. 2  showing the interface between oblong slot  80  in exhaust duct  30  and oblong spacer  56 , including flange  64 , connected to shaft  54 . Oblong spacer  56 , flange  64  and oblong slot  80  are shown in phantom under washer  58  in  FIG. 3  to show their relationship to duct  30 . In the embodiment shown, washer  58  comprises a circle having a diameter larger than the widest portion of oblong slot  80 . Shaft  54  extends through bore  84  ( FIG. 2 ) of washer  58  so that nut  60  can be attached to shaft  54 . Nut  60 , therefore, acts as a stop to prevent shaft  54  from passing through washer  58  and into exhaust duct  30 . In other embodiments, washer  58  may be non-circular or have other geometries so as to prevent passage of washer  58  through oblong slot  80 . 
         [0020]    Shaft  54  is also threaded into threaded bore  82  ( FIG. 2 ) of oblong spacer  56 , which is disposed within oblong slot  80 . Oblong spacer  56  is elongated so as to prevent rotation relative to exhaust duct  30 , thereby facilitating rotation and threading of shaft  54  into oblong spacer  56 . Oblong spacer  56  is smaller than oblong slot  80  to facilitate assembly of connector assembly  48  with exhaust duct  30 , as will be discussed later. Flange  64  is, however, wider than oblong slot  80  in at least one dimension to prevent dislodgement of oblong spacer  56 . Oblong spacer  56  and oblong slot  80  are shown having oval profiles in the described embodiment. However, oblong spacer  56  and oblong slot  80  can have any geometry that prevents relative rotation between the two features when torque is applied to shaft  54 . For example, each feature may be rectangular or hexagonal. Each feature need not have mating shapes. For example, oblong spacer  56  may be oval with oblong slot  80  being rectangular. 
         [0021]    O-ring  81  surrounds oblong spacer  56  and fills the gap present by the difference in size between oblong spacer  56  and oblong slot  80 . O-ring  81  prevents transfer of secondary air A S  ( FIG. 1 ) from exhaust duct  30  through oblong slot  80  and out of exhaust system  26  ( FIG. 1 ). For example, the interior of exhaust duct  30  is typically pressurized compared to the exterior of exhaust duct  30  due to the presence of secondary air A S  flowing through exhaust duct  30 . O-ring  81  is compressed against exhaust duct  30  by tightening of nut  60  on shaft  54  against washer  58 . Assembled as such, shaft  54  is prevented from passing through oblong slot  80  by nut  60  and washer  58 , but the radial position of shaft  54  relative to washer  58  can be adjusted by loosening nut  60  and rotating shaft  54  relative to oblong spacer  56 . In particular, shaft  54  is extended further into exhaust duct  30  to facilitate assembly of ball  66  into housing  70  ( FIG. 2 ), and retreated further out of exhaust duct  30  to put cable  52  ( FIG. 2 ) into tension. 
         [0022]      FIG. 4A  is a top view of rotating joint  50  of  FIG. 2  showing ball  66  engaging retention slot  76  in housing  70 .  FIG. 4B  is a side view of rotating joint  50  of  FIG. 2  showing ball  66  inserted into access opening  78  in housing  70 .  FIGS. 4A and 4B  are discussed concurrently. Housing  70  includes side wall  72 , end wall  74 , retention slot  76 , access opening  78  and feet  86 A and  86 B. Ball  66  and collar  68 , which includes socket  88 , are coupled to housing  70 . 
         [0023]    Side wall  72  comprises a hollow cylindrical body that has a diameter slightly larger than that of ball  66 . Side wall  72  extends radially outward from feet  86 A and  86 B, which comprise flat plates for joining to exhaust duct liner  32  ( FIG. 2 ). For example, feet  86 A and  86 B may include bores through which liner fasteners or studs can be inserted. Alternatively, feet  86 A and  86 B can be welded to an exhaust duct liner. In the disclosed embodiment, feet  86 A and  86 B provide housing  70  with a generally rectangular footprint, but may have other footprints such as square, oval or round. End wall  74  comprises a semi-spherical dome having a diameter slightly larger than that of ball  66 . Side wall  72 , end wall  74  and feet  86 A and  86 B may be integrally formed or may be welded together. For example, side wall  72 , end wall  74  and feet  86 A and  86 B may be stamped and machined from a steel plate. 
         [0024]    Opening  78  extends across side wall  72  to provide an opening large enough to receive ball  66 . In the embodiment shown, opening  78  accounts for half of side wall  72  by encompassing the entire width of side wall  72 . Opening  78  is additionally at least as tall as ball  66 . Thus, ball  66  can be moved through opening  78  so as to be between opposing portions of sidewall  72 . Slot  76  extends across a portion of end wall  74  to permit collar  68  and, when inserted into socket  88 , cable  52  ( FIG. 2 ) to extend radially from housing  70  toward connector assembly  48 . Slot  76  extends to the furthest radial extent of end wall  74  relative to feet  86 A and  86 B. Slot  76  thus sweeps through an angle slightly larger than ninety degrees on the semi-spherical dome of end wall  74 . Slot  76  is also slightly wider than collar  68  to permit rotation of ball  66  within end wall  74 . 
         [0025]    Housing  70  may have other shapes and geometries as compared to those shown and described in  FIGS. 4A and 4B . For example, ball  66  may comprise a cubic stop that fits into a rectilinear housing. However, in any embodiment, housing  70  permits axial or circumferential (with respect to the centerline of engine  10  in  FIG. 1 ) insertion of ball  66  into the interior of housing  70 , while restricting radial displacement of ball  66  from the interior of housing  70  after insertion. Further, after insertion of ball  66  into the interior of housing  70  and tensioning of cable  52  ( FIG. 2 ), end wall  74  prevents axial and circumferential movement of ball  66  so as to prevent disassembly of rotating joint  50 . 
         [0026]      FIG. 5  is a close-up of callout A of  FIG. 2  showing a cross-sectional view of collar  85  that connects cable  52  to connector assembly  48  of  FIG. 2 . Collar  85  comprises a cylindrical body having cylindrical socket  90 . The configuration of collar  85  and socket  90  shown in  FIG. 5  is also exemplary of collar  68  and socket  88  shown in  FIG. 4B  used to join cable  52  to ball  66 . Cable  52  is inserted into collar  85  such that a length of cable  52  extends across a mating length of socket  90 . Collar  85  and cable  52  are thereby provided with suitable parallel surface areas to provide coupling between the two bodies. In one embodiment, collar  85  and cable  52  are mechanically joined, such as with a swaged joint. In other embodiments, cable  52  and collar  85  are metallurgically joined, such as with a welded joint. Such joints, as are known in the art, provide couplings having tensile strengths at least as great as the cable to which they are joined. In the present invention, socket  90  includes contouring  92  to prevent damaging of cable  52  when exhaust duct liner  32  shifts axial or circumferential position. In the embodiment shown, contouring  92  comprises a flared or funnel shape that allows cable  52  to bend from collar  85  without extending across a sharp inflection point, such as the edge of socket  90 , thereby eliminating a stress point in cable  52 . As such, cable  52  is less likely to degrade or fail during operation of hanger  12 . 
         [0027]    With reference to  FIG. 2 , in order to assemble adjustable cable assembly  46  with exhaust duct  30  and exhaust duct liner  32 , housing  70  is first pre-assembled to exhaust duct liner  32 . Exhaust duct liner  32  is then inserted into exhaust duct  30  such that housing  70  roughly aligns with oblong slot  80  in exhaust duct  30 . Shaft  54 , cable  52 , collar  68  and ball  66  are also pre-assembled into a single component. For example, collar  68  and ball  66  are typically cast or machined from a single piece. Likewise, shaft  54 , collar  85  and wrenching feature  62  are cast or machined from a single piece. Cable  52  is then joined to collar  68  and collar  85  such that a single piece unit is formed. Shaft  54  is then threaded into oblong spacer  56  to form a sub-assembly. 
         [0028]    From the outside of exhaust duct  30 , ball  66  is inserted through oblong slot  80  by grasping onto shaft  54 . Shaft  54  is rotated so that one end of oblong spacer  56  and flange  64  can be inserted through oblong slot  80 . As indicated above, oblong slot  80  is larger than oblong spacer  56  to facilitate such entry. Further, the oblong shapes of slot  80  and spacer  56  ease the entry of shaft  54  into oblong slot  80  while attached to spacer  56 . Shaft  54  can then be rotated again to insert the second end of oblong spacer  56  through oblong slot  80  and bring flange  64  toward duct  30  at a later step in the assembly process. Ball  66  is moved into access opening  78  by movement of shaft  54 . Cable  52  is generally of sufficient diameter and stiffness to enable fine manual movements of ball  66 . Cable  52  is also sufficiently stiff such that, once ball  66  is inside housing  70 , shaft  54  can be released and shaft  54  will remain extended through slot  80 . Washer  58  is positioned onto shaft  54  and nut  60  is threaded onto shaft  54 . Nut  60  is not threaded down to engage washer  58  at this time. Shaft  54  is manually pulled outward, ensuring that ball  66  engages end wall  74 , to bring oblong spacer  56  into oblong slot  80  and flange  64  into engagement with exhaust duct  30 . 
         [0029]    At this point, the relative radial position of oblong spacer  56  with respect to exhaust duct  30  is checked to determine if shaft  54  needs to be further threaded into or out of oblong spacer  56 . Shaft  54  is threaded into a position that is predetermined to induce a desired amount of tension in cable  52 . For example, shaft  54  can be threaded into oblong spacer  56  so that oblong spacer  56  is a distance below the outer diameter surface of exhaust duct  30 . Then, nut  60  is tightened to bring the top of oblong spacer  56  into level alignment with the outer diameter surface of exhaust duct  30 , thereby stretching cable  52  and inducing a desired amount of tensile stress. Oblong spacer  56  is of a suitable thickness such that when washer  58  lies flat across oblong spacer  56  and exhaust duct  30  with nut  60  fully threaded, flange  64  will compress O-ring  81  to cause a sufficient seal. 
         [0030]    During operation of turbofan engine  10  ( FIG. 1 ), various temperature gradients within exhaust system  26  ( FIG. 1 ) produce local stresses and strains within liner  32 . Liner  32  is thereby subject to local distortions and displacements. Cable  52  and rotating joint  50  of the present invention prevent additional stress and strain from hanger  12  from being induced in liner  32 . However, cable  52  also permits hanger  12  to absorb radial tensile loading, such as when liner  32  moves away from duct  30 . As liner  32  tends to deform from loading and thermal gradients, hangers  12  distributed circumferentially around liner  32  allow exhaust duct  30  to react those loads to maintain the shape of liner  32  without hangers  12  inducing their own strain into liner  32 . For example, as liner  32  rotates clockwise and shifts left with reference to  FIG. 2 , rotating joint  50  permits the rotation while cable  52  permits the axial shifting. Cable  52  also permits circumferential movement as discussed above. Cable  52  neither pulls nor pushes on liner  32  to accommodate such movement due to the flexibility of cable  52 . However, pulling of cables  52  on the underside of exhaust duct  30  will maintain radial spacing between exhaust duct  30  and liner  32 , thereby retaining the shape of liner  32  and optimal performance. 
         [0031]    Hanger  12  is a simple to use system that facilitates easy installation. With the present invention, the use of tools or rigging to assemble ball  66  and cable  52  is not required. Hanger  12  only requires a single ball joint, thereby reducing the weight, complexity and number of parts as compared to prior art designs. Cable  52 , washer  58  and nut  60  comprise standard, off-the-shelf components thereby reducing the expense of hanger  12 . Furthermore, the inherent flexibility of cable  52  and the rotatability of rotating joint  50  allow exhaust duct liner  32  to move in all directions, except for radially apart from each other, without inducing stress in exhaust duct liner  32 . 
         [0032]    The following are non-exclusive descriptions of possible embodiments of the present invention. 
         [0033]    A hanger for use in a gas turbine engine exhaust system comprises: a connector assembly for connecting to an exhaust duct of the gas turbine exhaust system; a bracket for connecting to an exhaust duct liner of the gas turbine exhaust system; and a cable extending from the connector assembly to the bracket. 
         [0034]    The hanger of the preceding paragraph can optionally include, additionally and/or alternatively, any one or more of the following features, configurations and/or additional components: 
         [0035]    A hanger wherein the connector assembly comprises: a shaft to which the cable is connected; a washer having a bore through which the shaft extends; and a nut coupled to the shaft. 
         [0036]    A hanger further comprising an oblong spacer into which the shaft is threaded. 
         [0037]    A hanger wherein the oblong spacer includes a flange having a width larger than that of the oblong spacer. 
         [0038]    A hanger wherein the connector assembly further comprises an o-ring around the oblong body. 
         [0039]    A hanger wherein the shaft includes a socket into which the cable is inserted. 
         [0040]    A hanger wherein the socket is flared away from the cable. 
         [0041]    A hanger wherein the shaft includes a wrenching feature distally opposite the socket. 
         [0042]    A hanger wherein the cable includes a ball for connecting to the bracket. 
         [0043]    A hanger wherein the bracket comprises a housing having an access port for receiving the ball. 
         [0044]    A hanger wherein the housing comprises: a first wall for connecting to the exhaust duct liner; an opening extending through the first wall; a second wall connected to the first wall; and a slot disposed in the second wall, the slot having a width less than a width of the opening. 
         [0045]    A suspension system comprises: an exhaust duct of a gas turbine engine; an exhaust duct liner disposed within the exhaust duct; a shaft connected to an opening in the exhaust duct; a cable extending from the shaft into the exhaust duct; and a bracket connected to the exhaust duct liner and the cable. 
         [0046]    The suspension system of the preceding paragraph can optionally include, additionally and/or alternatively, any one or more of the following features, configurations and/or additional components: 
         [0047]    A suspension system further comprising: a nut coupled to the shaft outside of the exhaust duct. 
         [0048]    A suspension system further comprising: a washer disposed between the nut and the exhaust duct. 
         [0049]    A suspension system further comprising: a spacer disposed in the opening in the exhaust duct and through which the shaft extends. 
         [0050]    A suspension system further comprising a flange extending from the spacer beyond a perimeter of the opening. 
         [0051]    A suspension system further comprising an o-ring surrounding the spacer between the flange and the exhaust duct. 
         [0052]    A suspension system wherein the cable includes a stop for connecting to the bracket. 
         [0053]    A suspension system wherein the bracket comprises: a first wall connected to the exhaust duct liner; an opening extending through the first wall, the opening having a first width wider than the stop; a second wall connected to the first wall; and a slot disposed in the second wall, the slot having a second width narrower than the stop. 
         [0054]    An exhaust duct liner suspension system comprises: a shaft extending between first and second ends; a cable extending between first and second ends, the first end of the cable connected to the second end of the shaft; a stop connected to the second end of the cable; a spacer threaded onto the shaft; a nut threaded onto the shaft; and a washer positioned between the oblong spacer and the nut. 
         [0055]    The exhaust duct liner suspension system of the preceding paragraph can optionally include, additionally and/or alternatively, any one or more of the following features, configurations and/or additional components: 
         [0056]    An exhaust liner suspension system wherein: the spacer includes a flange; and an o-ring is disposed around the spacer adjacent the flange. 
         [0057]    While the invention has been described with reference to an exemplary embodiment(s), it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment(s) disclosed, but that the invention will include all embodiments falling within the scope of the appended claims.