Patent Publication Number: US-2020291813-A1

Title: Pressure relief door rotating exhaust deflector

Description:
BACKGROUND 
     1. Technical Field 
     This disclosure relates generally to core structures for gas turbine engines, and more particularly to a pressure relief system for the core cowling. 
     2. Background Information 
     The engine core of a gas turbine engine includes a core cowling which forms an exterior housing of the engine core. The core cowling is spaced from the engine core leaving a core compartment therebetween. Additionally, the core cowling encloses other engine core accessories, such pressurized air (e.g., compressor bleed air) lines or ducts, which may be disposed within the core compartment. The gases contained within these lines may have high temperatures and pressures which, if exposed to composite structural materials as a result of a rupture in the lines (i.e., a “burst duct event”), may cause damage to the composite structural materials. 
     In order to address the above-describe concerns, pressure relief doors have been used to vent high-temperature and high-pressure gases from the core compartment during a burst duct event. However, the high-temperature gases that have been vented from the core compartment may still damage or degrade the structure of the core cowling if they are allowed to “reattach” to the core cowling after venting. To address this concern, heat shields, such as titanium heat shields, have been used to protect portions of the core cowling located downstream from the pressure relief doors. However, these heat shields add weight to the gas turbine engine and require costly materials. Additionally, integration of the heat shield with the composite core cowling may reduce the structural strength of the core cowling. Accordingly, a need exists for an improved apparatus for relieving pressure within core compartments. 
     SUMMARY 
     According to an embodiment of the present disclosure, a housing includes a pressure relief door and a deflector. The pressure relief door includes a first door end disposed at a first hinge axis of the housing and an opposing second door end. The pressure relief door is rotatable between a first door position and a second door position about the first hinge axis and defines a portion of the housing in the first door position. The deflector includes a first deflector end disposed at a second hinge axis of the housing and an opposing second deflector end. The deflector is rotatable between a first deflector position and a second deflector position about the second hinge axis. Rotation of the pressure relief door from the first door position to the second door position effects rotation of the deflector from the first deflector position to the second deflector position. 
     In the alternative or additionally thereto, in the foregoing embodiment, the deflector in the second deflector position prevents rotation of the pressure relief door from the second door position to the first door position. 
     In the alternative or additionally thereto, in the foregoing embodiment, the pressure relief door is configured to rotate from the first door position to the second door position in response to an internal pressure of the housing greater than a predetermined pressure. 
     In the alternative or additionally thereto, in the foregoing embodiment, the deflector is configured to remain in the second deflector position, after rotating from the first deflector position to the second deflector position, until repositioned by a user. 
     In the alternative or additionally thereto, in the foregoing embodiment, the housing further includes a latch in communication with the housing and the pressure relief door. The latch is configured to secure the pressure relief door in the first position while the internal pressure of the housing is less than the predetermined pressure. 
     In the alternative or additionally thereto, in the foregoing embodiment, the deflector includes at least one scallop disposed in the second deflector end. 
     In the alternative or additionally thereto, in the foregoing embodiment, the housing further includes a lanyard connecting the pressure relief door and the deflector. 
     In the alternative or additionally thereto, in the foregoing embodiment, the lanyard connects the second door end to the second deflector end. 
     According to another embodiment of the present disclosure, a gas turbine engine includes an engine core and a core cowling enclosing the engine core. The core cowling includes a pressure relief door and a deflector. The pressure relief door includes a first door end disposed at a first hinge axis of the core cowling and an opposing second door end. The pressure relief door is rotatable between a first door position and a second door position about the first hinge axis and defines a portion of the core cowling in the first door position. The deflector includes a first deflector end disposed at a second hinge axis of the core cowling and an opposing second deflector end. The deflector is rotatable between a first deflector position and a second deflector position about the second hinge axis. Rotation of the pressure relief door from the first door position to the second door position effects rotation of the deflector from the first deflector position to the second deflector position. 
     In the alternative or additionally thereto, in the foregoing embodiment, the deflector in the second deflector position prevents rotation of the pressure relief door from the second door position to the first door position. 
     In the alternative or additionally thereto, in the foregoing embodiment, the deflector in the first deflector position is configured to shield an interface between the second door end and the core cowling from a heat source within an interior of the core cowling. 
     In the alternative or additionally thereto, in the foregoing embodiment, the pressure relief door is configured to rotate from the first door position to the second door position in response to an interior pressure of the core cowling greater than a predetermined pressure. 
     In the alternative or additionally thereto, in the foregoing embodiment, the gas turbine engine further includes a latch in communication with the core cowling and the pressure relief door. The latch is configured to secure the pressure relief door in the first position while the internal pressure of the core cowling is less than the predetermined pressure. 
     In the alternative or additionally thereto, in the foregoing embodiment, the deflector is configured to remain in the second deflector position, after rotating from the first deflector position to the second deflector position, until repositioned by a user. 
     In the alternative or additionally thereto, in the foregoing embodiment, the deflector, in the second deflector position, is configured to direct heated gases from an interior of the core cowling away from the core cowling. 
     In the alternative or additionally thereto, in the foregoing embodiment, bypass air flows along a bypass flow path adjacent the core cowling and the deflector directs the heated gases into a radially outer portion of the bypass flow path. 
     In the alternative or additionally thereto, in the foregoing embodiment, the deflector includes at least one scallop disposed in the second deflector end. 
     In the alternative or additionally thereto, in the foregoing embodiment, the deflector is downstream of the pressure relief door with respect to the bypass air flow. 
     In the alternative or additionally thereto, in the foregoing embodiment, the core cowling further includes a lanyard connecting the pressure relief door and the deflector. 
     According to another embodiment of the present disclosure, a gas turbine engine includes a nacelle, an engine core disposed within the nacelle, and a core cowling enclosing the engine core. The nacelle and the core cowling define a bypass flow path therebetween. The core cowling includes a pressure relief door, a deflector, and a lanyard connecting the pressure relief door and the deflector. The pressure relief door includes a first door end disposed at a first hinge axis of the core cowling and an opposing second door end. The pressure relief door is rotatable between a first door position and a second door position about the first hinge axis and defines a portion of the core cowling in the first door position. The deflector includes a first deflector end disposed at a second hinge axis of the core cowling and an opposing second deflector end. The deflector is rotatable between a first deflector position and a second deflector position about the second hinge axis. Rotation of the pressure relief door from the first position to the second position effects rotation of the deflector from the first deflector position to the second deflector position. 
     The deflector, in the second deflector position, is configured to direct heated gases from an interior of the core cowling into a radially outer portion of the bypass flow path. 
     The present disclosure, and all its aspects, embodiments and advantages associated therewith will become more readily apparent in view of the detailed description provided below, including the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates a side, cross-sectional view of a gas turbine engine. 
         FIG. 2  illustrates an exterior side view of an engine core cowling. 
         FIG. 3  illustrates an interior side view of an engine core cowling. 
         FIG. 4A  illustrates a pressure relief door in a shut position. 
         FIG. 4B  illustrates the pressure relief door of  FIG. 4A  in an open position. 
         FIG. 4C  illustrates the pressure relief door of  FIG. 4A  in an open position. 
         FIG. 5  illustrates an aft view of a pressure relief door in a shut position. 
         FIG. 6A  illustrates a front view of an exemplary deflector. 
         FIG. 6B  illustrates a front view of another exemplary deflector. 
     
    
    
     DETAILED DESCRIPTION 
     It is noted that various connections are set forth between elements in the following description and in the drawings. It is noted that these connections are general and, unless specified otherwise, may be direct or indirect and that this specification is not intended to be limiting in this respect. A coupling between two or more entities may refer to a direct connection or an indirect connection. An indirect connection may incorporate one or more intervening entities. 
     Referring to  FIG. 1  a gas turbine engine  10  generally includes a fan section  12 , a compressor section  14 , a combustor section  16 , a turbine section  18 , and an exhaust section  19  disposed about an axial centerline  20 . The gas turbine engine  10  further includes a nacelle  22  defining an exterior housing of the gas turbine engine  10  about the axial centerline  20 . The nacelle  22  includes an outer barrel  24  defining a radially outermost surface of the nacelle  22  and an inner barrel  26  defining a radially innermost surface of the nacelle  22 . 
     An engine core  28  generally includes all or part of the fan section  12 , compressor section  14 , combustor section  16 , turbine section  18 , and exhaust section  19 . A core cowling  30  (i.e., a core nacelle or core shroud) defines an exterior housing of the engine core  28  about the axial centerline  20 . In some embodiments, all or part of the core cowling  30  may be made of, for example, composite materials or any other suitable material. While the present disclosure is discussed with respect to aircraft gas turbine engines, it should be understood that the present disclosure is not limited to use in gas turbine engines or aircraft and may be applied to any other suitable vehicle, industrial application, or environment where compartment pressure relief is desirable. 
     The inner barrel  26  and the core cowling  30  may generally define an annular bypass duct  32  therebetween. The fan section  12  drives air along a bypass flow path B through the gas turbine engine  10 . At least a portion of the bypass flow path B may pass through the bypass duct  32 . As will be discussed in further detail, the bypass flow path B through the bypass duct  32  may be referred to in terms of a radially outer bypass flow path B 1  and a radially inner bypass flow path B 2 . The compressor section  14  drives air along a core flow path C, separate from the bypass flow path B, for compression and communication into the combustor section  16  and then expansion through the turbine section  18 . 
     Referring to  FIGS. 2, 3, and 5 , the core cowling  30  may include one or more pressure relief doors  34  configured to release high-pressure and high-temperature gases from a compartment of the engine core  28 , for example, during a burst duct event. For example, a plurality of pressure relief doors  34  may be circumferentially spaced about the core cowling  30 . The pressure relief door  34  may be rotatably mounted to the core cowling  30  by, for example, one or more hinges  36 . For example, the hinges  36  may be configured to permit rotation of the pressure relief door  34  about a hinge axis  36 A. In some embodiments, the hinge axis  36 A may be substantially perpendicular to the bypass flow path B. The core cowling  30  includes a pressure relief opening  35  corresponding to the pressure relief door  34 . The opening  35  has a first end  35 E 1  and an opposing second end  35 E 2 . The opening  35  additionally has a first side  35 S 1  and a second side  35 S 2 , each side  35 S 1 ,  35 S 2  extending between the first end  35 E 1  and the second end  35 E 2 . As used herein, the term “substantially” with regard to an angular relationship refers to the noted angular relationship +/−10 degrees. 
     In some embodiments, the pressure relief door  34  may be disposed on an aft portion of the core cowling  30  proximate the exhaust section  19  to ensure that high-temperature gases exiting the pressure relief door  34  do not damage the nacelle  22  and core cowling  30 . For example, the pressure relief door  34  may be disposed proximate the aft end of the nacelle  22 . The core cowling  30  includes a downstream portion  31  disposed downstream of the pressure relief door  34 . In some embodiments, the downstream portion  31  may include a heat shield  31 S configured to protect the structure of the downstream portion  31  from high-temperature gases exiting through the pressure relief door opening  35 . The heat shield  31 S may be, for example, titanium or any other suitable high-temperature resistant material. In some embodiments, the heat shield  31 S may be an integral to the downstream portion  31  of the core cowling  30 . In some other embodiments, inclusion of a heat shield  31 S to protect the structure of the downstream portion  31  may not be necessary. 
     As will be discussed in further detail, the pressure relief door  34  is rotatable between an open position (see  FIG. 4B ) and a closed position (as shown in  FIGS. 2, 3, and 4A ). As used herein, the “closed position” will be used to refer to the pressure relief door  34  in a position so as to form a substantially continuous exterior surface with the core cowling  30  (i.e., the pressure relief door  30  is in a standard position for operation of the gas turbine engine  10 ). As used herein, the “open position” will be used to refer to the pressure relief door  34  in a position other than the closed position (i.e., the pressure relief door  34  is partially open, fully open, etc.). 
     The pressure relief door  34  may include one or more latches  38  configured to secure the pressure relief door  34  in the shut position during normal operation of the gas turbine engine  10 . The latch  38  may be configured to release the pressure relief door  34  upon the occurrence of a predetermined condition, for example, a high pressure in the interior of the core cowling  30 . Actuation of the latch  38  to release the pressure relief door  34  may be accomplished by any suitable means including, for example, a pressure sensing spring, or a hydraulically, pneumatically, or electrically actuated release mechanism in communication with an associated sensor (e.g., a pressure sensor). In some embodiments, the interior pressure of the core cowling  30  may be sufficient to rotate the pressure relief door  34  from the closed position to the open position once the latch is released. In some other embodiments, the pressure relief door  34  may include an apparatus configured to effect rotation of the pressure relief door  34  from the closed position to the open position. 
     Referring to  FIGS. 4A, 4B, and 5 , the pressure relief door  34  is shown in a closed position ( FIG. 4A ) and an open position ( FIG. 4B ), respectively. The pressure relief door  34  includes a first end  34 E 1  and an opposing second end  34 E 2 . The first end  34 E 1  may be rotatably coupled to the core cowling  30  of the engine core  28  by the hinges  36  about the hinge axis  36 A. The second end  34 E 2  is disposed proximate the core cowling  30  thereby defining an interface  39  between the pressure relief door  34  and the core cowling  30 . In some embodiments, the second end  34 E 2  of the door may be substantially flush with the core cowling  30  at the interface  39 . In the closed position, the pressure relief door  34  may form a portion of the core cowling  30  (i.e., the exterior surface of the pressure relief door may form a substantially continuous exterior surface of the core cowling  30 . 
     The core cowling  30  may include one or more deflectors  40  configured to direct high-temperature gases from a core compartment  28 C of the engine core  28  away from the downstream portion  31  of the core cowling  30 , for example, during a burst duct event. The deflector  40  may be positioned relative to a respective pressure relief door  34  so as to operate together to relieve an interior pressure of the core compartment  28 C. The deflector  40  includes a first end  40 E 1  and an opposing second end  40 E 2 . The deflector  40  may be rotatably mounted to the core cowling  30  at the first end  40 E 1  by, for example, one or more hinges  42 . For example, the hinges  42  may be configured to permit rotation of the deflector about a hinge axis  42 A. In some embodiments, the hinge axis  42 A may be substantially perpendicular to the bypass flow path B and/or substantially parallel to the hinge axis  36 A. As shown in  FIGS. 4A and 4B , in some embodiments, the pressure relief door  34  may be rotatably mounted to the core cowling  30  proximate the first end  35 E 1  of the opening  35  while the deflector  40  is rotatably mounted to the core cowling  30  proximate the second end  35 E 2  of the opening  35 . For example,  FIG. 4A  shows the deflector  40  in a closed position while  FIG. 4B  shows the deflector  40  in an open position. In some embodiments, the deflector  40  may be disposed downstream (i.e., with respect to the bypass flow path B) and/or aft of the pressure relief door  34 . 
     As shown in  FIG. 4B , in some embodiments, the pressure relief door  34  and corresponding deflector  40  may include a lanyard  44  connecting the pressure relief door  34  to the deflector  40 . Rotation of the pressure relief door from the closed position to the open position may effect a corresponding rotation of the deflector  40  from the closed position to the open position. Rotation of the pressure relief door  34 , as a result of gases venting from the core compartment  38 C, may cause the pressure relief door  34  to pull the deflector  40  from the closed position to the open position via the lanyard  44 . In some embodiments, the lanyard  44  may connect the second end  34 E 2  of the pressure relief door  34  to the second end  40 E 2  of the deflector  40 . In some other embodiments, rotation of the deflector  40  from the closed position to the open position, in response to rotation of the pressure relief door  34  from the closed position to the open position, may not require a lanyard  44  connecting the pressure relief door  34  to the deflector  40 . For example, rotation of the deflector  40  from the closed position to the open position may be effected by a spring or other biasing device or, alternatively, by the force of gases venting from the compartment  28 C (e.g., gases venting substantially along a vent flow path V). Thus, rotation of the pressure relief door  34  from the closed position to the open position may release the deflector  40  to rotate from the closed position to the open position. 
       FIG. 5  illustrates a side view of an exemplary pressure relief door  34  from an aft perspective. The pressure relief door  34  of  FIG. 5  has an orientation with respect to the core cowling  30  which is substantially similar to the orientation of the pressure relief door  34  as shown in  FIGS. 4A and 4B . As shown in  FIG. 5 , in some embodiments, more than one deflector  40  may be rotatably mounted to the core cowling  30 , for example, proximate and aligned with the first side  35 S 1  of the opening  35  and the second side  35 S 2  of the opening  35 . Accordingly, in embodiments including a lanyard  44  connecting the pressure relief door  34  to the deflector  40 , each deflector of the more than one deflector  40  may include a lanyard  44  connecting the respective deflector  40  to the pressure relief door  34 . Rotation of the pressure relief door  34 , about the hinge axis  36 A, from the closed position to the open position, may thereby effect rotation of the more than one deflector  40  from the closed position to the open position about the hinge axis  42 A. 
     As previously discussed, the core cowling  30  encloses one or more ducts or lines containing high-temperature and/or high-pressure gas. An equipment failure leading to a rupture from one of the ducts into the core compartment  28 C (i.e., a burst duct event) may rapidly fill the core compartment  28 C with the high-temperature and/or high-pressure gas. In response to the burst duct event, the latch  38  may release the pressure relief door  34  from the closed position, thereby allowing the pressure relief door  34  to rotate to the open position. Rotation of the pressure relief door  34  to the open position may further effect rotation of the deflector  40  from the closed position to the open position via the lanyard  44 . 
     Referring to  FIG. 4B , in the open position, the deflector  40  directs high-temperature gas from the core compartment  28 C into the bypass flow path B thereby forcing the high-temperature gas to mix with the relatively cooler bypass air. For example, high-temperature gas may be vented from the core compartment  28 C substantially along the vent flow path V. As a result, high-temperature gas may be prevented from reattaching to and possibly damaging the downstream portion  31 . In other words, high-temperature fluids are directed sufficiently far into the bypass flowpath B (e.g., radially away from the core cowling  30 ) such that the gas do not deleteriously interact with (i.e., reattach to) the downstream portion  31 . For example, high-temperature gas may be directed towards the outer bypass flow path B 1  wherein reattachment of high-temperature gas with the downstream portion  31  is reduced or eliminated. In other words, heat gases directed towards the outer bypass flow path B 1  may not deleteriously affect the downstream portion  31 . In some embodiments, a maximum amount that the pressure relief door  34  may rotate in direction R 1  may depend on a length L 1  of the lanyard  44  and/or a length L 2  of the deflector  40 . 
     Referring to  FIG. 4B and 4C , during a burst duct event, the pressure relief door  34  may reach an equilibrium position wherein the force of the bypass flow path B on the exterior of the pressure relief door  34  equals the force of the vent flow path V venting from the core compartment  38 C. Subsequent to the rotation of the pressure relief door  34  to the open position, pressure within the core compartment  38 C may be reduced or returned substantially to a typical operating pressure of the core compartment  38 C, thereby causing the pressure relief door  34  to rotate in direction R 2  towards the core cowling  30 . 
     As shown in  FIG. 4C , in some embodiments, the deflector  40  is configured to remain in the open position after rotating from the shut position to the open position, for example, in response to a burst duct event. The deflector  40  in the open position may prevent the pressure relief door  34  from returning to the closed position. In said embodiments, the presence of the pressure relief door  34  and the deflector  40  in the respective open positions may provide a visual indication to ground crew personnel or other equipment technicians that a burst duct event or other equipment malfunction has occurred. Thus, the deflector  40  may remain in the open position until repositioned by a user (e.g., ground crew personnel). 
     Referring to  FIGS. 6A and 6B , the deflector  40  may have a substantially rectangular cross-sectional shape (see  FIG. 6A ). In other embodiments, the deflector  40  may include one or more scallops  46  disposed in the second end  40 E 2  of the deflector to provide better mixing of high-temperature fluids from the core compartment  38 C with the air in the bypass flow path B. The scallops  46  may have any suitable length L 3  and/or width W to effect mixing of the high-temperature fluids. In some embodiments, one or more scallops  46  may have a different length L 3  and/or width W than one or more other scallops  46 . 
     In some embodiments, operation of the pressure relief door  34  and the deflector  40  to prevent reattachment of high-temperature fluids to the downstream portion  31  may reduce or eliminate the need for the heat shield  31 S in the downstream portion  31 . Elimination of the heat shield  31 S may provide for an overall reduction in the weight of the core cowling  30  and, thus, the weight of the gas turbine engine  10 . Further, elimination of the heat shield  31 S may result in greater structural strength of the core cowling  30  by allowing a more continuous composite structure which could otherwise be damaged by vented high-temperature fluids. The increased continuous composite structure may provide additional surface area for acoustic attenuating structures, such as honeycomb structures, on the core cowling  30 , thereby providing increased sound attenuation proximate the downstream portion  31 . 
     Referring again to  FIG. 4A , in some embodiments, the deflector  40  in the closed position may be configured to shield the interface  39  between the pressure relief door  34  and the core cowling  30  from a heat source (e.g., a heat source of the engine core  28  as a result of general gas turbine engine  10  operation or a mechanical failure such as a burst duct) within the core compartment  28 C. For example, the deflector  40  may be disposed between the interface  39  and the heat source in order to prevent excessive temperatures in composite portions of the interface  39 . In some embodiments, the deflector  40  may be made of a high-temperature resistant material such as titanium or any other suitable material for shielding the interface  39 . 
     While various aspects of the present disclosure have been disclosed, it will be apparent to those of ordinary skill in the art that many more embodiments and implementations are possible within the scope of the present disclosure. For example, the present disclosure as described herein includes several aspects and embodiments that include particular features. Although these particular features may be described individually, it is within the scope of the present disclosure that some or all of these features may be combined with any one of the aspects and remain within the scope of the present disclosure. Accordingly, the present disclosure is not to be restricted except in light of the attached claims and their equivalents.