An aircraft engine nacelle lap joint structure

Abstract

The application provides a lap joint structure for an aircraft engine nacelle, belonging to the technical field of engine nozzles, which is installed on the outer surface of an engine nozzle and circumferentially arranged with a ring of lap joint units. The lap joint units include the following four types: an oil discharge lap joint structure arranged directly below in the circumferential direction, the oil discharge lap joint structure being provided with a through oil discharge structure; a general lap joint structure arranged directly above in the circumferential direction and on the left and right sides of the oil discharge lap joint structure; a straight section lap joint structure arranged on the left and right sides in the circumferential direction and used for avoiding a rear body feature structure of an aircraft, the straight section lap joint structure being provided with an air inlet duct overflow area; a reinforced lap joint structure arranged on the left and right sides of the straight section lap joint structure, and the side of the reinforced lap joint structure away from the straight section lap joint structure being arranged adjacent to the general lap joint structure; and a cooperation gap is reserved between adjacent lap joint units to prevent structural interference when the lap joint units are compressed. The scheme reduces the aerodynamic resistance of the aircraft.

Description

Technical Field

[0001] This application relates to the field of engine nozzle technology, and more particularly to a structure for connecting with an aircraft engine nacelle. Background Technology

[0002] On the outside of the exhaust system's tail nozzle, there is an elastic sheet that overlaps with the engine nacelle skin of the aircraft's rear fuselage. This sheet can be used to cover the components inside the engine nacelle, achieving integration of the engine with the aircraft's rear fuselage profile. The streamlined outer surface has a flow-straightening effect, reducing the aircraft's aerodynamic drag.

[0003] In traditional design, the engine aft fuselage and the aircraft aft fuselage are often separated, resulting in a significant abrupt change in their surfaces. This generates numerous vortices, shock waves, and flow separation in the transition area, creating additional aerodynamic drag. With the development of aviation and the increasing demands on fuel efficiency, reducing aerodynamic drag has become a core design focus. Smooth surface designs in the transition area can effectively reduce overall aircraft drag, thereby lowering fuel consumption and improving flight range, endurance, and maneuverability. Simultaneously, the increasing spatial coupling between the engine aft fuselage and the aft fuselage, coupled with the need for a compact layout, further drives the coupled design of their structures. Furthermore, the engine nacelle overlap structure, as a crucial area for the emission of waste fuel from the engine, guides the smooth discharge of this fuel, preventing high-temperature fuel from directly impacting the aircraft aft fuselage and reducing the complexity of aft fuselage material selection and design. Therefore, the design of the aircraft engine nacelle overlap structure is particularly important. Summary of the Invention

[0004] In view of this, the present application provides a structure for connecting with an aircraft engine nacelle. This structure can improve the streamlined transition between the aircraft and the rear body of the engine, reduce flow separation, reduce the aerodynamic drag of the rear body of the aircraft, and the grille on the connecting structure can guide the smooth discharge of engine waste fuel.

[0005] This application provides a connection structure for an aircraft engine nacelle. The connection structure is installed on the outer surface of the engine nozzle and has a ring of connection units arranged circumferentially. The connection units include the following four types: An oil drain overlap structure is provided at the circumferentially lower position, and a through oil drain structure is provided on the oil drain overlap structure; The general type of overlapping structure is set at the top of the circumferential direction and on the left and right sides of the oil drainage overlapping structure; The straight section overlap structure is located on the left and right sides in the circumferential direction to avoid the characteristic structure of the rear body of the aircraft. The straight section overlap structure has a reserved air intake overflow area. A reinforced overlapping structure is provided on both sides of the straight overlapping structure, with the side of the reinforced overlapping structure away from the straight overlapping structure being adjacent to a general overlapping structure. A fitting gap is reserved between adjacent overlapping units to prevent structural interference when the overlapping units are compressed.

[0006] According to a specific implementation of an embodiment of this application, the size of the mating clearance satisfies the following relationship: , Where d is the size of the fit clearance, R is the radius of the fit clearance at different axial positions from the center line of the nozzle rear body, N is the number of circumferentially distributed fit clearances, and ΔR is the maximum compression radius of the overlapping unit, with ΔR ranging from 3mm to 4mm.

[0007] According to a specific implementation of an embodiment of this application, the surface of the general type overlap structure, the oil drainage overlap structure, and the reinforced overlap structure all include three parts sequentially along the axial direction: The front section is an overlapping section, used to overlap with the rear skin of the aircraft. The middle section is a transition section surface, used to smoothly guide and transition the airflow coming from the front; The rear section is a straight section, used to fit and conform to the outer shape of the engine nozzle's rear body. The front, middle and rear sections are integrated into one unit.

[0008] According to one specific implementation of an embodiment of this application, a plurality of positioning holes are provided on the straight section.

[0009] According to a specific implementation of the present application, the overlapping section is provided with a first synchronous limiting piece and a second synchronous limiting piece. The first synchronous limiting piece and the second synchronous limiting piece are disposed opposite to each other on two sides of the overlapping unit. One end of the first synchronous limiting piece and the second synchronous limiting piece are fixed to one of the two adjacent overlapping units, and the other end of the first synchronous limiting piece and the second synchronous limiting piece are fixed to the other of the two adjacent overlapping units. The first synchronous limiting piece and the second synchronous limiting piece form an interlocking constraint relationship between adjacent overlapping units in the circumferential direction.

[0010] According to one specific implementation of the present application, the reinforced overlapping structure is formed by merging two adjacent general overlapping structures into one, and the strength of the reinforced overlapping structure is higher than that of the general overlapping structure.

[0011] According to one specific implementation of the present application, the outer contour of the straight section overlapping structure remains straight along the engine axis.

[0012] According to one specific implementation of an embodiment of this application, the oil draining structure is configured as a grille hole.

[0013] According to one specific implementation of the embodiments of this application, each overlapping unit is provided with a weight reduction groove.

[0014] According to a specific implementation of the present application, the overlapping section is set as an L-shaped structure, the corner of the L-shaped structure is matched with the internal reinforcing rib of the aircraft rear body, and the bottom end of the L-shaped structure is connected to the middle section.

[0015] Beneficial effects: The overlapping structure with the aircraft engine compartment in this embodiment of the application has the following beneficial effects: a) Four types of overlapping units in a circumferential ring can be used to cover the components inside the cavity of the aircraft engine nacelle, realize the integration of the engine and the rear body surface of the aircraft, and the streamlined outer surface plays a straightening effect to reduce the aerodynamic drag of the aircraft. b) The overlapping structure can guide the smooth discharge of waste lubricating oil, avoid the high-temperature lubricating oil directly washing the rear fuselage of the aircraft, and reduce the difficulty of the material selection and design of the rear fuselage. c) The overlapping structure is equipped with a straight section overlapping structure, which can be used to avoid the characteristic structure of the rear body of the aircraft and ensure that the gas overflowing into the aircraft body from the air intake can be smoothly discharged from here. d) The reserved fitting gap between each overlapping structure can be designed according to the relationship between the gap size d and the radius R from the center line, so as to avoid structural interference between the overlapping structures when the overlapping structure is compressed. e) The synchronous limiting plate set at the front of the overlapping structure is used to limit the deformation of each baffle in the circumferential direction, which can ensure that there will be no large difference in compression deformation of each baffle when the external airflow is uneven. Attached Figure Description

[0016] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a circumferential perspective view of an overlapping structure according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the circumferential structure of the overlapping structure according to an embodiment of the present invention; Figure 3 This is a schematic cross-sectional view of an overlapping structure according to an embodiment of the present invention; Figure 4 This is a schematic diagram of a synchronization limiting piece structure according to an embodiment of the present invention; Figure 5 This is a schematic diagram of the design of reserved gaps at different radii according to an embodiment of the present invention; Figure 6 This is a schematic diagram of R according to an embodiment of the present invention; Figure 7 This is a schematic diagram of a straight section overlapping structure according to an embodiment of the present invention.

[0018] In the diagram: 01-Aircraft rear body external profile; 02-Aircraft rear body internal reinforcing rib; 03-Engine nozzle rear body external profile; 1-General type overlapping structure; 2-Fuel drain overlapping structure; 2a-Grate hole; 3-Straight section overlapping structure; 4-Reinforced overlapping structure; 5-Overflow area; 6-Match clearance; 7-Overlap section; 8-Transition section profile; 9-Straight section; 10-Positioning hole; 11-Weight reduction groove; 12-First synchronous limit plate; 13-Second synchronous limit plate. Detailed Implementation

[0019] The embodiments of this application will now be described in detail with reference to the accompanying drawings.

[0020] The following specific examples illustrate the implementation of this application. Those skilled in the art can easily understand other advantages and effects of this application from the content disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. This application can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this application. It should be noted that, in the absence of conflict, the following embodiments and features in the embodiments can be combined with each other. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0021] It should be noted that various aspects of embodiments within the scope of the appended claims are described below. It will be apparent that the aspects described herein can be embodied in a wide variety of forms, and any particular structure and / or function described herein is merely illustrative. Based on this application, those skilled in the art will understand that one aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number of aspects set forth herein can be used to implement the device and / or practice the method. Additionally, this device and / or method can be implemented using structures and / or functionalities other than one or more of the aspects set forth herein.

[0022] It should also be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of this application. The illustrations only show the components related to this application and are not drawn according to the number, shape and size of the components in actual implementation. In actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0023] Furthermore, specific details are provided in the following description to facilitate a thorough understanding of the examples. However, those skilled in the art will understand that the described aspects can be practiced without these specific details.

[0024] This application provides a structure for connecting with an aircraft engine nacelle for a gas turbine engine exhaust system, as shown in the attached figure. Figures 1 to 7 Provide a detailed description.

[0025] In one embodiment, a joint structure for connecting with an aircraft engine nacelle is provided. The joint structure is mounted on the outer surface of the engine nozzle and has a ring of joint units arranged circumferentially. The joint units include the following four types: Oil drain overlap structure 2 is located at the circumferentially lower position, and the oil drain overlap structure 2 has a through oil drain structure. General type of overlap structure 1 is set at the top of the circumference and on the left and right sides of the oil drainage overlap structure 2; The straight section overlapping structure 3 is set on the left and right sides in the circumferential direction to avoid the characteristic structure of the rear body of the aircraft. The straight section overlapping structure 3 has a reserved air intake overflow area 5. The reinforced overlapping structure 4 is disposed on both sides of the straight overlapping structure 3, and the side of the reinforced overlapping structure 4 away from the straight overlapping structure 3 is disposed adjacent to the general overlapping structure 1. A fitting gap 6 is reserved between adjacent overlapping units to prevent structural interference when the overlapping units are compressed.

[0026] In this embodiment, the outlines of the oil drain overlap structure 2, the general overlap structure 1, the straight section overlap structure 3, and the reinforced overlap structure 4 are all adapted to the outer surface of the engine nozzle. Each overlap unit is attached and fixed to the outer surface of the nozzle on the side facing the nozzle, and the side away from the nozzle is matched with the outer surface 01 of the aircraft rear body. This satisfies the thermal deformation compensation requirements during engine operation and also achieves a sealed transition between the cabin and the nozzle.

[0027] In specific implementation, refer to Figure 1 and Figure 2A straight-section overlapping structure 3 is set on each of the left and right sides of the entire circumference. Its purpose is to avoid the characteristic structure of the aircraft's rear fuselage. The air intake overflow area 5 reserved on the straight-section overlapping structure 3 ensures that the gas overflowing into the aircraft body from the air intake can be smoothly discharged. Due to the high wind pressure near the overflow area 5, reinforced overlapping structures 4 are set at both ends of the straight-section overlapping structure 3. Multiple general overlapping structures 1 are set between the two reinforced overlapping structures 4 located on the upper side of the entire circumference. Three oil drain overlapping structures 2 are located directly below the entire circumference. The oil drain overlapping structures 2 are used to discharge waste fuel oil, preventing high-temperature fuel oil from directly washing over the aircraft's rear fuselage and reducing the difficulty of material selection and design for the aircraft's rear fuselage. General overlapping structures 1 are set between the two reinforced overlapping structures 4 and the oil drain overlapping structures 2 located on the lower side of the entire circumference. A fitting gap 6 is reserved between each overlapping structure to prevent structural interference when the overlapping structures are compressed.

[0028] Furthermore, refer to Figure 5 and Figure 6 The size of the fitting clearance 6 satisfies the following relationship: , Where d is the size of the mating gap 6, R is the radius of the location of the mating gap 6 at different axial positions from the center line of the nozzle rear body, N is the number of circumferentially evenly distributed mating gap 6, and ΔR is the maximum compression radius of the overlapping unit, with ΔR ranging from 3mm to 4mm.

[0029] In this embodiment, the relationship between the gap size d and the radius R from the center line is designed to avoid structural interference in various overlapping structures when the overlapping structure is compressed.

[0030] In one embodiment, refer to Figure 3 The general type lap joint structure 1, the oil drainage lap joint structure 2, and the reinforced lap joint structure 4 all consist of three parts along the axial direction: The front section is overlapping section 7, which is used to overlap with the rear skin of the aircraft. The middle section is a transition section surface 8, which is used to smoothly guide and transition the airflow coming from the front; The rear section is a straight section 9, which is used to fit and conform to the rear external profile 03 of the engine nozzle. The front, middle and rear sections are integrated into one unit.

[0031] In this embodiment, the integrated molding surface structure can avoid the splicing seams caused by segmented connections from affecting the airflow field, while reducing the overall processing difficulty of the structure, improving the structural strength of each segment connection position, and avoiding the problem of cracking at the connection position after long-term airflow scouring.

[0032] A clearance is provided between the overlapping section 7 and the aircraft's rear fuselage skin to compensate for the relative displacement between the aircraft's rear fuselage and the engine nozzle, preventing deformation and damage caused by rigid structural tension. The transition section surface 8 is a smoothly transitioning arc surface, with its curvature gradually matching the outer contour curvature of the engine nozzle along the axial direction from front to back. This allows airflow to flow smoothly over the overlapping structure surface, avoiding airflow separation or additional aerodynamic drag. The straight section 9 matches the outer surface of the engine nozzle, preventing local protrusions or depressions from interfering with the flow field, while also withstanding the high-temperature loads during nozzle operation, maintaining structural stability.

[0033] Furthermore, the straight section 9 is provided with multiple positioning holes 10.

[0034] Preferably, the straight section 9 is provided with three positioning holes 10, which can be arranged in a triangular pattern to enhance structural stability.

[0035] Furthermore, refer to Figure 4 The overlapping section 7 is provided with a first synchronous limiting piece 12 and a second synchronous limiting piece 13. The first synchronous limiting piece 12 and the second synchronous limiting piece 13 are arranged opposite to each other on two sides of the overlapping unit. One end of the first synchronous limiting piece 12 and the second synchronous limiting piece 13 is fixed to one of the two adjacent overlapping units, and the other end of the first synchronous limiting piece 12 and the second synchronous limiting piece 13 is fixed to the other of the two adjacent overlapping units. The first synchronous limiting piece 12 and the second synchronous limiting piece 13 form an interlocking constraint relationship between adjacent overlapping units in the circumferential direction.

[0036] In this embodiment, by setting a synchronous limiting plate to limit the deformation of each overlapping structure around the circumference, it can be ensured that individual baffles will not have large differences in compression deformation when the external airflow is uneven.

[0037] Furthermore, the reinforced overlapping structure 4 is formed by merging two adjacent general overlapping structures 1 into one piece, and the strength of the reinforced overlapping structure 4 is higher than the strength of the general overlapping structure 1. In this embodiment, The integrated, one-piece structure eliminates the fitting gap 6 between the two general-type overlapping structures 1, significantly improving the overall structural rigidity at this location. It also simplifies the assembly process and reduces the risk of structural interference at this point. The airflow overflow area 5 near the straight section of the overlapping structure 3 experiences higher wind pressure, and the aerodynamic load in this area is greater than in other circumferential locations. Higher structural strength meets the load-bearing requirements, preventing fatigue deformation caused by long-term uneven loads on the overlapping structure and extending its overall service life. The outer contour of the reinforced overlapping structure 4 remains consistent with the outer contour of the original two general-type overlapping structures 1, without altering the original flow channel morphology. This avoids additional interference to the external flow field of the nozzle and ensures the continuous smoothness of the entire overlapping structure surface.

[0038] In one embodiment, refer to Figure 7 The outline of the straight section overlapping structure 3 is kept straight along the engine axis. This design can effectively avoid the characteristic structure of the aircraft rear body without cutting or modifying the original characteristic structure. It will not affect the overall structural strength of the aircraft rear body. At the same time, it can ensure that the gas exhaust path of the air intake overflow area 5 is not blocked, and the airflow can flow smoothly. It avoids the increase of overflow resistance caused by structural obstruction, which affects the working efficiency of the air intake.

[0039] In one embodiment, the oil draining structure is configured as a grille hole 2a.

[0040] In one embodiment, each overlapping unit is provided with a weight reduction groove 11.

[0041] In one embodiment, the overlapping section 7 is configured as an L-shaped structure, with the corner of the L-shaped structure engaging with the internal reinforcing rib 02 of the aircraft's rear body, and the bottom edge of the L-shaped structure connecting to the middle section.

[0042] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A structure for connecting with an aircraft engine nacelle, characterized in that, The overlapping structure is installed on the outer surface of the engine nozzle, and a ring of overlapping units is arranged around the circumference. The overlapping units include the following four types: An oil drain overlap structure (2) is located at the circumferentially lower position, and a through oil drain structure is provided on the oil drain overlap structure (2); The general type of overlap structure (1) is set at the top of the circumferential direction and on the left and right sides of the oil drainage overlap structure (2); The straight section overlap structure (3) is set on the left and right sides of the circumference to avoid the rear body feature structure of the aircraft. The straight section overlap structure (3) has an air intake overflow area (5). The reinforced overlapping structure (4) is located on both sides of the straight overlapping structure (3), and the side of the reinforced overlapping structure (4) away from the straight overlapping structure (3) is adjacent to the general overlapping structure (1). A fitting gap (6) is reserved between adjacent overlapping units to prevent structural interference when the overlapping units are compressed.

2. The structure for connecting with the aircraft engine compartment according to claim 1, characterized in that, The size of the fitting clearance (6) satisfies the following relationship: ， Where d is the size of the fitting gap (6), R is the radius of the fitting gap (6) at different axial positions from the center line of the nozzle rear body, N is the number of circumferentially evenly distributed fitting gaps (6), ΔR is the maximum compression radius of the overlapping unit, and the value of ΔR ranges from 3mm to 4mm.

3. The overlapping structure with the aircraft engine compartment according to claim 1, characterized in that, The general lap joint structure (1), the oil drainage lap joint structure (2), and the reinforced lap joint structure (4) all consist of three parts along the axial direction: The front section is the overlapping section (7), which is used to overlap with the rear skin of the aircraft; The middle section is a transition section surface (8), which is used to smoothly guide the airflow coming from the front; The rear section is a straight section (9), which is used to fit and cooperate with the rear outer surface (03) of the engine nozzle; The front, middle and rear sections are integrated into one unit.

4. The structure for connecting with the aircraft engine compartment according to claim 3, characterized in that, Multiple positioning holes (10) are provided on the straight section (9).

5. The overlapping structure with the aircraft engine nacelle according to claim 3, characterized in that, The overlapping section (7) is provided with a first synchronous limiting piece (12) and a second synchronous limiting piece (13). The first synchronous limiting piece (12) and the second synchronous limiting piece (13) are arranged opposite to each other on two sides of the overlapping unit. One end of the first synchronous limiting piece (12) and the second synchronous limiting piece (13) is fixed to one of the two adjacent overlapping units, and the other end of the first synchronous limiting piece (12) and the second synchronous limiting piece (13) is fixed to the other overlapping unit of the two adjacent overlapping units. The first synchronous limiting piece (12) and the second synchronous limiting piece (13) form an interlocking constraint relationship between the adjacent overlapping units in the circumferential direction.

6. The structure for connecting with the aircraft engine nacelle according to claim 1, characterized in that, The reinforced overlapping structure (4) is formed by merging two adjacent general overlapping structures (1) into one piece. The strength of the reinforced overlapping structure (4) is higher than that of the general overlapping structure (1).

7. The structure for connecting with the aircraft engine nacelle according to claim 1, characterized in that, The outline of the straight section overlapping structure (3) remains straight along the engine axis.

8. The structure for connecting with the aircraft engine nacelle according to claim 1, characterized in that, The oil draining structure is configured with a grid hole (2a).

9. The structure for connecting with the aircraft engine nacelle according to claim 1, characterized in that, Each overlapping unit is equipped with a weight reduction groove (11).

10. The structure for connecting with the aircraft engine compartment according to claim 3, characterized in that, The overlapping section (7) is set as an L-shaped structure. The corner of the L-shaped structure is matched with the internal reinforcing rib (02) of the rear body of the aircraft. The bottom edge of the L-shaped structure is connected to the middle section.

Images