Abstract:
A bellows for transporting exhaust from an engine to a nozzle has a section that is axially moveable and bendable about an axis extending therethrough, a first joint for attaching the section to the engine wherein the section is movable radially relative to the axis, and a second joint for attaching the section to the nozzle.

Description:
BACKGROUND 
       [0001]    In some aircraft applications, an exhaust nozzle is mounted remotely from an engine. By mounting the nozzle remotely from the engine, the aircraft may have enhanced and desirable flight characteristics. This means generally that there is a connector between the engine exhaust and nozzles. 
       SUMMARY 
       [0002]    According to an exemplar disclosed herein, a bellows for transporting exhaust from an engine to a nozzle has a section that is axially moveable and bendable about an axis extending therethrough, a first joint for attaching the section to the engine wherein the section is movable radially relative to the axis, and a second joint for attaching the section to the nozzle. 
         [0003]    According to a further exemplar disclosed herein, a bellows system for an aircraft includes a multi-piece nozzle, a gas turbine engine that generates thrust, a section that is axially moveable and bendable about an axis extending therethrough, the section transporting the exhaust to the nozzle, a first joint attaching the section to the engine wherein the section is movable radially relative to the axis, and a second joint attaching the section to the nozzle. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0004]    The various features and advantages of the disclosed examples will become apparent to those skilled in the art from the following detailed description. The drawings that accompany the detailed description can be briefly described as follows. 
           [0005]      FIG. 1  is a cross sectional view, partially in phantom, of an engine and remote nozzle installed in an aircraft and having a compliant sealing joint therebetween. 
           [0006]      FIG. 2  is a cross sectional view of the compliant sealing joint used for the aircraft of  FIG. 1 . 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0007]    Referring now to the Figures, a gas turbine engine  10  is shown in cross section in an aircraft  15 . The gas turbine engine  10  has a high pressure turbine  20 , a low pressure turbine  22 , a compressor  25 , and a fan section  30 . During operation, gas turbine engine exhaust  40  is directed through a bellows section  45  to an adjustable, multi-portion nozzle  50  that is mounted in the aircraft  15  independently of the gas turbine engine  10 . The bellows section  45  allows aircraft designers the flexibility to optimize nozzle and gas turbine engine placement within the aircraft  15  to achieve required aircraft operating parameters. It also provides mechanical flexibility and helps prevent air leakage during operation. Various types of nozzle  50  may be compatible with this design, ranging from a straight axial nozzle (phantom lines) to an off-axis thrust nozzle (solid lines), or a vectoring nozzle which can move between the two positions. 
         [0008]    The bellows section  45  includes a corrugated body  55 , a forward, first joint  60  (e.g., near the engine) and an aft, second joint  65  (e.g., near the nozzle). The first joint  60  attaches the body  55  to an aft portion  70  of the gas turbine engine  10  and conducts the exhaust  40  to the nozzle  50 . The second joint  65  attaches the body  55  to the nozzle  50 . The body  55  is corrugated to allow for bending moments along and relative to an axis  75  that extends through the engine to the nozzle  50 . Body  55  also allows axial deformations. 
         [0009]    The first joint  60  includes a circular retaining flange  80  that is attached to an abutment  85  encircling the aft portion  70  of the engine  10 . The retaining flange  80  has a hook-like, bent-over portion  87  that creates a recess  90  that receives a bellows flange  95 . The bellows flange  95  may move radially within the recess  90  to allow radial sliding of the body  55  that may be required given relative movements between the nozzle  50  and the engine  10  during operation thereof. 
         [0010]    The bellows flange  95  has an axially extending first portion  100 , a radially extending second portion  105 , an axially extending third portion  110  and a radially extending fourth portion, e.g., the bellows flange  95 . The axially extending first portion  100  is attached to the body  55  and is riveted to a finger seal  120 . 
         [0011]    The finger seal  120  is metallic and has a circular flange  130  that abuts and is riveted to the axially extending first portion  100 . The finger seal also has an angled portion  135  that is angled toward the axis  75  and the engine  10 , and abuts the axially extending third portion  110  and the retaining flange  80 . By being riveted to the axially extending second portion  100  and contacting the retaining flange  80 , leakage from the engine  10  between the the bellows flange  95  and the circular retaining flange  80  is minimized Because the angled portion  135  contacts the axially extending third portion  110  and the retaining flange  80  at an angle, pressure of the engine exhaust  40  tends to force the angled portion  135  against the retaining flange  80  during operation, even if the bellows flange  95  is moving axially within the retaining flange  80 . 
         [0012]    As stated hereinabove, the bellows section  45  has several corrugations  140  that allow axial and rotational movement about the axis  75  that may be caused by moments on the gas turbine engine  10 , the nozzle  50  and the exhaust  40  passing therethrough. The bellow section  45  is axially moveable and may accommodate movement up and down or side to side or combinations thereof. The bellows section  45  is constructed of a material, such as titanium or nickel, which may adjust to the bending requirements of the aircraft  15 . 
         [0013]    The second joint  65  includes a circular flange  145  attached to the body  55  and a circular hooked appendage  150  attached to or integral with the nozzle  50 . The hooked appendage  150  fits over the circular flange  145  in a close-fitting interference manner and may be crimped. The close fit of the second joint  65  allows the second joint  65  to accommodate different thermal coefficients of expansion if the body  55  and the nozzle  50  are made of dissimilar materials like titanium and nickel. A rope seal  155  is disposed in a groove  160  disposed at an end  165  of the circular flange  145  between the hooked appendage  150  and the circular flange  145  to minimize exhaust  40  leakage therebetween. Though a close fitting attachment is shown, the attachment of the second joint may also be done by other means such as bolting. 
         [0014]    The bellows section  45  is then able to absorb axial and rotational displacements of the nozzle relative to the engine while minimizing exhaust leakage  40 . The bellows section  45  and the first joint  60  allow for larger displacements thereof to accommodate movement of the nozzle  50 , which is typically multi-piece, to achieve higher deflections of the nozzle  50  while posing less stresses on the bellows section  45  as compared to a fixed joint (not shown) between the body  55  and the engine  10 . 
         [0015]    Although a combination of features is shown in the illustrated examples, not all of them need to be combined to realize the benefits of various embodiments of this disclosure. In other words, a system designed according to an embodiment of this disclosure may not necessarily include all of the features shown in any one of the Figures or all of the portions schematically shown in the Figures. Moreover, selected features of one example embodiment may be combined with selected features of other example embodiments. 
         [0016]    The preceding description is exemplary rather than limiting in nature. Variations and modifications to the disclosed examples may become apparent to those skilled in the art that do not necessarily depart from the essence of this disclosure. The scope of legal protection given to this disclosure can only be determined by studying the following claims.