Patent Publication Number: US-2022221056-A1

Title: Non-metallic engine case inlet compression seal for a gas turbine engine

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a divisional of U.S. patent application Ser. No. 16/108,758, filed Aug. 22, 2018, which is a divisional of U.S. patent application Ser. No. 14/948,657, filed Nov. 23, 2015, now U.S. Pat. No. 10,077,669, Issued Sep. 18, 2018, which claims the benefit of provisional application Ser. No. 62/084,603, filed Nov. 26, 2014. 
    
    
     BACKGROUND 
     The present disclosure relates to a gas turbine engine and, more particularly, to a non-metallic engine case inlet compression seal therefor. 
     Gas turbine engines, such as those which power modern military aircraft, include a compressor section to pressurize a supply of air, a combustor section to burn a hydrocarbon fuel in the presence of the pressurized air, and a turbine section to extract energy from the resultant combustion gases and generate thrust. Downstream of the turbine section, an augmentor section, or “afterburner”, is operable to selectively increase thrust. The increase in thrust is produced when fuel is injected into the core gases downstream of the turbine section and burned with the oxygen contained therein to generate a second combustion that is then passed through a variable area nozzle system. 
     In gas turbine powered aircraft, especially military aircraft, location of the gas turbine engine within the airframe reduces drag and signature. The internal engine location, however, necessarily requires airflow to be routed through an intake duct in the airframe to the engine. The intake duct is typically integrated with the airframe and interfaces with the engine case inlet via a compression seal interface to effectively communicate airflow to the engine. The compression seal interface often includes a K-seal mounted to the airframe and a J-seal mounted to the engine. Typically, the K-seal is non-metallic and the J-seal are manufactured of a titanium material. Although effective, the J-seal may be relatively difficult to manufacture and may be susceptible to cycle fatigue. 
     SUMMARY 
     A non-metallic engine case inlet compression seal for a gas turbine engine, according to one disclosed non-limiting embodiment of the present disclosure includes a non-metallic arcuate interface section; a non-metallic longitudinal leg section that extends from the non-metallic arcuate interface section; and a non-metallic mount flange section that extends from the longitudinal leg section. 
     A further embodiment of the present disclosure includes, wherein the non-metallic arcuate interface section has a durometer different than that of the non-metallic longitudinal leg section. 
     A further embodiment of any of the foregoing embodiments of the present disclosure includes, wherein the non-metallic arcuate interface section has a durometer different than that of the non-metallic mount flange section. 
     A further embodiment of any of the foregoing embodiments of the present disclosure includes, wherein the non-metallic longitudinal leg section has a durometer different than that of the of the non-metallic mount flange section. 
     A further embodiment of any of the foregoing embodiments of the present disclosure includes, wherein each of the non-metallic arcuate interface section, the non-metallic longitudinal leg section, and the non-metallic mount flange section have a different durometer. 
     A further embodiment of any of the foregoing embodiments of the present disclosure includes, wherein each of the non-metallic arcuate interface section, the non-metallic longitudinal leg section, and the non-metallic mount flange section are integral. 
     A further embodiment of any of the foregoing embodiments of the present disclosure includes, wherein each of the non-metallic arcuate interface section, the non-metallic longitudinal leg section, and the non-metallic mount flange section are integral. 
     A further embodiment of any of the foregoing embodiments of the present disclosure includes, wherein each of the non-metallic arcuate interface section, the non-metallic longitudinal leg section, and the non-metallic mount flange section are manufactured of a silicone rubber. 
     A further embodiment of any of the foregoing embodiments of the present disclosure includes, wherein the non-metallic arcuate interface section, the non-metallic longitudinal leg section, and the non-metallic mount flange section form a circular “J” seal. 
     A further embodiment of any of the foregoing embodiments of the present disclosure includes, wherein the non-metallic mount flange has a multiple of apertures. 
     A further embodiment of any of the foregoing embodiments of the present disclosure includes, wherein at least one of the non-metallic arcuate interface section, the non-metallic longitudinal leg section, and the non-metallic mount flange section includes fiber reinforcement. 
     A further embodiment of any of the foregoing embodiments of the present disclosure includes, wherein the fiber reinforcement includes an aramid material. 
     A further embodiment of any of the foregoing embodiments of the present disclosure includes, a fiber reinforcement that impregnates at least one of the non-metallic arcuate interface section, the non-metallic longitudinal leg section, and the non-metallic mount flange section. 
     A further embodiment of any of the foregoing embodiments of the present disclosure includes, a fiber reinforcement bonded to an outer surface of at least one of the non-metallic arcuate interface section, the non-metallic longitudinal leg section, and the non-metallic mount flange section. 
     A further embodiment of any of the foregoing embodiments of the present disclosure includes, wherein the non-metallic arcuate interface section forms a bulb. 
     A further embodiment of any of the foregoing embodiments of the present disclosure includes, an interface to the bulb to receive air to pressurize the bulb. 
     A non-metallic engine case inlet compression seal for a gas turbine engine, according to another disclosed non-limiting embodiment of the present disclosure includes an non-metallic arcuate interface section, the non-metallic arcuate interface section forms a bulb; and an interface to the bulb to receive and air to pressurize the bulb. 
     A further embodiment of any of the foregoing embodiments of the present disclosure includes, a non-metallic longitudinal leg section that extends from the non-metallic arcuate interface section. 
     A further embodiment of any of the foregoing embodiments of the present disclosure includes a non-metallic mount flange section that extends from the longitudinal leg section. 
     A further embodiment of any of the foregoing embodiments of the present disclosure includes, wherein each of the non-metallic arcuate interface section, the non-metallic longitudinal leg section, and the non-metallic mount flange section are manufactured of a silicone rubber. 
     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. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Various features will become apparent to those skilled in the art from the following detailed description of the disclosed non-limiting embodiment. The drawings that accompany the detailed description can be briefly described as follows: 
         FIG. 1  is a general schematic view of an example gas turbine engine with a nozzle section according to one disclosed non-limiting embodiment; 
         FIG. 2  is a phantom view of an airframe illustrating a non-metallic engine case inlet compression seal between an aircraft intake duct and an engine case inlet of the gas turbine engine; 
         FIG. 3  is an exposed sectional of the non-metallic engine case inlet compression seal mounted to an engine case; 
         FIG. 4  is a partial perspective view of the non-metallic engine case inlet compression seal according to one disclosed non-limiting embodiment; 
         FIG. 5  is a sectional view of the non-metallic engine case inlet compression seal according to one disclosed non-limiting embodiment; 
         FIG. 6  is a sectional view of the non-metallic engine case inlet compression seal according to one disclosed non-limiting embodiment; 
         FIG. 7  is a sectional view of the non-metallic engine case inlet compression seal according to one disclosed non-limiting embodiment; and 
         FIG. 8  is a sectional view of the non-metallic engine case inlet compression seal according to one disclosed non-limiting embodiment. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  schematically illustrates a gas turbine engine  20 . The gas turbine engine  20  is disclosed herein as a two-spool, low-bypass, augmented turbofan that generally incorporates a fan section  22 , a compressor section  24 , a combustor section  26 , a turbine section  28 , an augmenter section  30 , a duct section  32 , and a non-metallic engine case inlet compression seal  34  along a central longitudinal engine axis A. Although depicted as an augmented low bypass turbofan in the disclosed non-limiting embodiment, it should be appreciated that the concepts described herein are applicable to other gas turbine engines including non-augmented engines, geared architecture engines, direct drive turbofans, turbojet, turboshaft, multi-stream variable cycle, and other engine architectures with a nozzle system. 
     An outer case structure  36  and an inner case structure  38  define a generally annular secondary airflow path  40  around a core airflow path  42 . Various structures and modules may define the outer case structure  36  and the inner case structure  38  which essentially define an exoskeleton to support rotational hardware therein. Air that enters the fan section  22  is divided between core airflow through the core airflow path  42 , and secondary airflow through the secondary airflow path  40 . The core airflow passes through the combustor section  26 , the turbine section  28 , then the augmentor section  30 , where fuel may be selectively injected and burned to generate additional thrust through the non-metallic engine case inlet compression seal  34 . 
     The secondary airflow may be utilized for a multiple of purposes to include, for example, cooling, pressurization and variable cycle operations. The secondary airflow as defined herein is any airflow different from the core airflow. The secondary airflow may ultimately be at least partially injected into the core airflow path  42  adjacent to the duct section  32  and the non-metallic engine case inlet compression seal  34 . It should be appreciated that additional airflow streams, such as third stream airflow typical of variable cycle engine architectures, may additionally be provided. 
     With reference to  FIG. 2 , the engine  20  is removably located within an airframe  50  (illustrated schematically). It should be appreciated that various airframe  50  configurations will benefit herefrom. The airframe  50  generally includes an engine bulkhead  52 , an engine bay  54 , an inlet  56 , and an intake duct  58 . The intake duct  58  is integrated within, or forms a portion of, the airframe  50 . The bulkhead  52  is located generally between the intake duct  58  and the engine bay  54 . 
     With reference to  FIG. 3 , the engine  20 , which is situated in the engine bay  54 , is coupled to the intake duct  58  by a compression interface formed by a bulkhead seal  60  and a non-metallic engine case inlet compression seal  70  ( FIG. 4 ). The bulkhead seal  60 , such as a K-seal, is mounted to the bulkhead  52 . The non-metallic engine case inlet compression seal  70 , such as J-seal, is mounted to the outer case structure  36 . Thus, the engine  20  is sealed with the intake duct  58  through the compression interface formed by the J-seal and the K-seal such that air is routed from the inlet  56  to the engine  20 . For clarity, only a circumferential portion of the non-metallic engine case inlet compression seal  70  and the bulkhead seal  60  are shown. Normally, the non-metallic engine case inlet compression seal  70  and the bulkhead seal  60  entail full 360° rings, of either a single piece or ring segments. 
     The bulkhead seal  60  generally includes an inner leg  62 , an outer leg  64 , and a mount flange  66 . The inner leg  62  and the outer leg  64  at least partially receive the non-metallic engine case inlet compression seal  70  therebetween. The mount flange  66  permits attachment of the bulkhead seal  60  to the engine bulkhead  52 . The bulkhead seal  60  is typically manufactured of an alloy such as titanium. It should be appreciated that various configurations may be provided. 
     With reference to  FIG. 5 , the non-metallic engine case inlet compression seal  70  generally includes a non-metallic arcuate interface section  72 , a non-metallic longitudinal leg section  74 , and a non-metallic mount flange section  76 . The non-metallic arcuate interface section  72  extends from the non-metallic longitudinal leg section  74  to, in this example, form a generally “J” shape. The non-metallic mount flange section  76  extends transversely from the non-metallic longitudinal leg section  74  and includes a multiple of apertures  78 . Each of the apertures  78  receives a fastener  80  to mount the non-metallic engine case inlet compression seal  70  to the outer case structure  36  forward of the fan section  22 . In this embodiment, the non-metallic engine case inlet compression seal  70  extends from the outer case structure  36  from the forward circumferential edge of the fan section  22  forward of an engine mount  82  ( FIG. 3 ). 
     The non-metallic longitudinal leg section  74  may include a stepped surface  84  that abuts a forward edge  86  of the outer case structure  36 . Alternatively, the non-metallic longitudinal leg section  74  may form an aperture  88  ( FIG. 6 ) at least partially through the stepped surface  84  to receive a sensor  90  (illustrated schematically) such as a pressure sensor therein. The aperture  88 , in this example, is continuous with the stepped surface  84 . 
     The non-metallic engine case inlet compression seal  70  is manufactured of a non-metallic material  100  such as silicone rubber formed, or extruded, to shape. It should be appreciated that various non-metallic materials may be utilized. The cross section and stiffness of the non-metallic engine case inlet compression seal  70  is arranged to seal the interface irrespective of relative motion between the airframe  50  and the engine  20  such as is typical during maneuvering flight. 
     With reference to  FIG. 7 , in another disclosed non-limiting embodiment, the material  100  may include fiber reinforcement  110  with, for example, meta-aramid material fibers. The fiber reinforcement  110  may be utilized to impregnate the non-metallic engine case inlet compression seal  70  to provide strength and stiffness, alternatively, or in addition thereto, fiber reinforcement  120  may, be bonded to the outer surfaces of the non-metallic engine case inlet compression seal  70  to provide strength and durability. In one example, the fiber reinforcement  110  may be located to directly contact upon the bulkhead seal  60  for strength, reduced friction, etc. In another example, the fiber reinforcement  110  may be located as reinforcement for strength or increased bond strength. It should be appreciated that beyond mechanical retention of fasteners the non-metallic engine case inlet compression seal  70  may also be retained via bonding. The material  100  may further include various coatings to, for example, increase lubricity, heat resistance, etc. 
     In another disclosed non-limiting embodiment, one or more of the non-metallic arcuate interface section  72 , the non-metallic longitudinal leg section  74 , and the non-metallic mount flange section  76 , may be manufactured of different non-metallic materials. In one example, the non-metallic mount flange section  76  may be manufactured of a material that has a relatively higher durometer than that of the non-metallic arcuate interface section  72 , yet be integrated thereto such as via co-molding, over-molding, or other such manufacturing process. In another disclosed non-limiting embodiment, the non-metallic longitudinal leg section  74  may be manufactured of a relatively rigid non-metallic material, or include an insert  130  thereof. 
     With reference to  FIG. 8 , in another disclosed non-limiting embodiment, an non-metallic engine case inlet compression seal  70 A may include a non-metallic arcuate interface section  72 A that forms a bulb  140 . The bulb  140  may include an interface  142  to receive air from an air pressure source to pressurize a pressurization region  144  formed by the bulb  140 . The air pressure source, for example, may be secondary airflow sourced from the secondary airflow path  40  ( FIG. 1 ). The bulb  140  is thereby pressurized to facilitate formation of a conforming compression seal that readily provide an increased contact surface with the bulkhead seal  60 . That is, the pressurization region  144  thereby drives the bulb  140  into the bulkhead seal  60  to increase contact therewith. 
     The non-metallic engine case inlet compression seal is relatively uncomplicated to manufacture yet provides for relatively complex geometries that may include one or more pressurized regions. The non-metallic material also provides for considerable design options such as shape, durometer, coatings, reinforcement, and/or pressurization. The non-metallic engine case inlet compression seal readily tolerates application temperatures and provides flexibility of design for unique properties at various sections such as rigid and stiff at fastening location, flexible and resilient at a seal interface, and/or rigid where pressure sensors or other features may be installed. The non-metallic engine case inlet compression seal is also relatively insensitive to shipping and handling conditions. The non-metallic engine case inlet compression seal also avoids the necessity of metallic seal stop crack drilling may be readily mended. 
     The use of the terms “a,” “an,” “the,” and similar references in the context of description (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or specifically contradicted by context. The modifier “about” used in connection with a quantity is inclusive of the stated value and has the meaning dictated by the context (e.g., it includes the degree of error associated with measurement of the particular quantity). All ranges disclosed herein are inclusive of the endpoints, and the endpoints are independently combinable with each other. It should be appreciated that relative positional terms such as “forward,” “aft,” “upper,” “lower,” “above,” “below,” and the like are with reference to normal operational attitude and should not be considered otherwise limiting. 
     Although the different non-limiting embodiments have specific illustrated components, the embodiments of this invention are not limited to those particular combinations. It is possible to use some of the components or features from any of the non-limiting embodiments in combination with features or components from any of the other non-limiting embodiments. 
     It should be appreciated that like reference numerals identify corresponding or similar elements throughout the several drawings. It should also be appreciated that although a particular component arrangement is disclosed in the illustrated embodiment, other arrangements will benefit herefrom. 
     Although particular step sequences are shown, described, and claimed, it should be understood that steps may be performed in any order, separated or combined unless otherwise indicated and will still benefit from the present disclosure. 
     The foregoing description is exemplary rather than defined by the limitations within. Various non-limiting embodiments are disclosed herein, however, one of ordinary skill in the art would recognize that various modifications and variations in light of the above teachings will fall within the scope of the appended claims. It is therefore to be understood that within the scope of the appended claims, the disclosure may be practiced other than as specifically described. For that reason the appended claims should be studied to determine true scope and content.