A tail nozzle structure suitable for a double-ducted turbofan engine

Abstract

A tail nozzle structure suitable for a dual-duct turbofan engine relates to the technical field of aero-engines and is used to reduce the difficulty of stably connecting the tail nozzle to a dual-duct turbofan engine. A tail nozzle structure suitable for a dual-duct turbofan engine comprises an inner cone, a middle casing and an outer casing arranged in sequence from the inside to the outside, an inner duct is arranged between the inner cone and the middle casing, and an outer duct is arranged between the middle casing and the outer casing. The structure is characterized in that at least two connecting brackets are fixedly connected to the inner cone, each connecting bracket is distributed circumferentially around the inner cone, the outer end of the connecting bracket is fixedly connected to the outer casing, the middle casing is fixedly connected to the connecting bracket, and a flange is provided on the middle casing, which is detachably connected to the stator of the engine.

Description

Technical Field

[0001] The invention relates to the technical field of aviation engines, in particular to a tail nozzle structure suitable for a double-ducted turbofan engine. Background Art

[0002] With the development of the aviation industry and the needs of military combat missions, the demand for micro-turbofan engines is increasing. With the requirements of low cost and high reliability, many components of micro-turbofan engines cannot simply use the structure of large turbofan engines, but must be appropriately improved or innovated. The design of the tail nozzle is one of them.

[0003] The existing double-duct turbofan engine includes an inner cone, a middle casing and an outer casing arranged in sequence from the inside to the outside, an inner duct is provided between the inner cone and the middle casing, and an outer duct is provided between the middle casing and the outer casing. Among them, the inner cone is fixedly connected to the fixing parts in the engine through a connecting piece, the middle casing is fixedly connected to the engine stator through a flange, and the outer casing is fixedly connected to the engine outer casing through a flange. There is no connecting piece between the middle casing and the outer casing. In order to ensure the stability of the outer casing, this structure must improve the strength of the connecting assembly between the outer casing and the engine outer casing. However, in order to improve the strength, it is necessary to make adaptive adjustments to the structure, size and even material of the engine outer casing, which greatly increases the cost of production and design. This also increases the difficulty of connecting the tail nozzle. At the same time, the above-mentioned connection scheme in the prior art also makes all the loads of the outer casing act on the area between the outer casing and the engine outer casing, and this area needs to be provided with a seal, which will lead to the seal wear and pressure loss rate of this area. Summary of the invention

[0004] The object of the present invention is to provide a tail nozzle structure suitable for a dual-duct turbofan engine, so as to reduce the difficulty of stably connecting the tail nozzle to the dual-duct turbofan engine.

[0005] The technical solution adopted by the present invention to solve the technical problem is:

[0006] A tail nozzle structure suitable for a dual-duct turbofan engine comprises an inner cone, a middle casing and an outer casing arranged in sequence from the inside to the outside, an inner duct is arranged between the inner cone and the middle casing, an outer duct is arranged between the middle casing and the outer casing, at least two connecting brackets are fixedly connected to the inner cone, each connecting bracket is distributed circumferentially around the inner cone, the outer end of the connecting bracket is fixedly connected to the outer casing, the middle casing is fixedly connected to the connecting bracket, a flange is provided on the middle casing, and the flange is detachably connected to the stator of the engine.

[0007] The beneficial effect is that the connecting bracket connects the inner cone, the middle casing and the outer casing together, and the flange is connected to the stator, thereby supporting and fixing the outer casing, which will greatly reduce the force at the connection between the outer casing and the outer casing of the engine, which is conducive to reducing the design and processing costs, and is also conducive to protecting the sealing structure between the outer casing and the outer casing of the engine, which is conducive to improving the service life. Since the stator itself is a structural component, the additional force caused by the indirect connection of the outer casing is far less than the surplus of its bearing capacity, so there is no need to adjust the stator structure. The surplus space can be fully used to share the force there. At the same time, in addition to playing the role of airflow diversion, the inner cone also plays the role of an internal support member - it plays the role of structural support and bearing for the middle casing and the outer casing, avoiding deformation of the middle casing and the outer casing, and maintaining the accuracy of the inner and outer duct volumes.

[0008] Furthermore, the inner end of the connecting bracket is welded to the inner cone.

[0009] The beneficial effect is: it is helpful to maintain the stability of the structure.

[0010] Furthermore, each of the connecting brackets is welded to the middle casing respectively.

[0011] The beneficial effect is: it is helpful to maintain the stability of the structure.

[0012] Furthermore, the outer end of the connecting bracket is detachably connected to the outer casing via a screw.

[0013] The beneficial effect is that the disassembly, assembly and maintenance of the invention are facilitated.

[0014] Furthermore, a screw seat for inserting the screw member is provided on the outer casing, and a threaded hole for cooperating with the screw member is provided on the outer end of the connecting bracket.

[0015] The beneficial effect is that the connection work of the screw parts is convenient.

[0016] Furthermore, the screw seat is welded to the outer casing.

[0017] The beneficial effect is that it is convenient to process the screw seat on the present invention.

[0018] Furthermore, a threaded hole seat is embedded in the connecting bracket, and a threaded hole seat is provided on the threaded hole seat for cooperating with the screw member.

[0019] The beneficial effect is that the processing of the threaded hole is facilitated.

[0020] Furthermore, a guide angle is provided on the front side of the connecting bracket, and the guide angle is arranged forward.

[0021] The beneficial effects are: it helps to reduce the resistance of airflow and improve the efficiency of the engine. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 A schematic diagram of an embodiment of the present invention;

[0023] Figure 2 for Figure 1 An enlarged view of part A in FIG.

[0024] Figure 3 A three-dimensional schematic diagram of an implementation method of an inner cone, a middle casing and a connecting bracket;

[0025] Figure 4 for Figure 3 A schematic diagram of the main view;

[0026] Figure 5 for Figure 4 BB cross-sectional diagram;

[0027] In the figure: 1 stator, 11 rotating shaft, 12 turbofan, 13 engine outer casing, 2 inner cone, 3 middle casing, 31 flange part, 4 outer casing, 41 screw part, 42 screw seat, 5 inner duct, 6 outer duct, 7 connecting bracket, 71 threaded hole seat, 72 guide angle. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] like Figure 1 and Figure 3 As shown, for the technical solution of setting the threaded hole for cooperating with the screw member 41, Figure 1 and Figure 3 Two different solutions are embodied. For the technical solution of the hole position distribution for the sleeve bolt on the flange 31, Figure 1 and Figure 3 Two different distribution schemes are embodied.

[0030] like Figures 1 to 5As shown, a tail nozzle structure suitable for a double-bypass turbofan engine, wherein the double-bypass turbofan engine includes a stator 1 and a rotating shaft 11 rotatably arranged relative to the stator 1, and a turbofan 12 is arranged on the rotating shaft 11. A tail nozzle structure suitable for a double-bypass turbofan engine includes an inner cone 2, a middle casing 3 and an outer casing 4 arranged in sequence from the inside to the outside, and the inner cone 2 is defined as being arranged "backward" relative to the rotating shaft 11. An inner duct 5 is arranged between the inner cone 2 and the middle casing 3, and an outer duct 6 is arranged between the middle casing 3 and the outer casing 4. At least two connecting brackets 7 are fixedly connected to the inner cone 2, and each connecting bracket 7 is distributed circumferentially around the inner cone 2. The outer end of the connecting bracket 7 is fixedly connected to the outer casing 4, and the middle casing 3 is fixedly connected to the connecting bracket 7. A flange 31 is provided on the middle casing 3, and the flange 31 is detachably connected to the stator 1 of the engine. The inner end of the connecting bracket 7 is welded to the inner cone 2. Each connecting bracket 7 is welded to the middle casing 3 respectively. The outer end of the connecting bracket 7 is detachably connected to the outer casing 4 by means of a screw 41. The inner cone 2, the middle casing 3, the outer casing 4 and the connecting bracket 7 can be made of stainless steel such as S304 and S310, and brazing, argon arc welding and the like can be used for welding. The optimal number of the connecting brackets 7 is three or four. The outer casing 4 is connected to the outer casing of the engine by means of a bolt group, and a seal is provided.

[0031] like Figures 1 to 5 As shown, an assembly method of a tail nozzle structure suitable for a double-ducted turbofan engine is as follows: the inner cone 2, the middle casing 3, and the connecting bracket 7 are processed into an integrated structure by welding → the flange 31 is then fixed to the stator 1 by bolts → the outer casing 4 is fixed to the outer end of the connecting bracket 7 → the outer casing 4 is connected to the engine outer casing 13.

[0032] like Figures 1 to 5 As shown, the beneficial effects of the present invention are: the connecting bracket 7 connects the inner cone 2, the middle casing 3 and the outer casing 4 to each other, and the flange 31 is connected to the stator 1, thereby supporting and fixing the outer casing 4, which will greatly reduce the force at the connection between the outer casing 4 and the engine outer casing 13, which is conducive to reducing the design and processing costs, and is also conducive to protecting the sealing structure between the outer casing 4 and the engine outer casing 13, which is conducive to improving the service life. Since the stator 1 itself is a structural component, the additional force caused by the indirect connection of the outer casing 4 is far less than the surplus of its bearing capacity, so there is no need to adjust the stator structure. The surplus space can be fully used to share the force at this place. At the same time, in addition to playing the role of airflow diversion, the inner cone 2 also plays the role of an internal support member-playing the role of structural support and bearing for the middle casing 3 and the outer casing 4, avoiding the deformation of the middle casing 3 and the outer casing 4, and maintaining the accuracy of the inner and outer duct volumes.

[0033] like Figure 1 and Figure 2As shown, the outer casing 4 is provided with a screw seat 42 for inserting the screw member 41, and the outer end of the connecting bracket 7 is provided with a threaded hole for cooperating with the screw member 41. The screw seat 42 is welded to the outer casing 4. The connecting bracket 7 is embedded with a threaded hole seat 71, and the threaded hole seat 71 is provided with a threaded hole for cooperating with the screw member 41.

[0034] like Figure 3 -to Figure 5 As shown, for the technical solution of the threaded hole, the threaded hole can also be directly opened at the end of the connecting bracket.

[0035] like Figure 3 As shown, a guide angle 72 is provided on the front side of the connecting bracket 7. The guide angle 72 is arranged forward to help reduce the resistance to the airflow, thereby ensuring the working efficiency of the engine.

[0036] In this embodiment, the connecting bracket adopts a solid structure. In addition, the connecting bracket can also adopt a hollow structure. The connecting bracket with a hollow result can also be produced by sheet metal processing through sheet metal, thereby helping to reduce the overall weight of the aircraft.

Claims

1. A tail nozzle structure suitable for a double-duct turbofan engine, comprising an inner cone, a middle casing and an outer casing arranged in sequence from the inside to the outside, an inner duct is arranged between the inner cone and the middle casing, and an outer duct is arranged between the middle casing and the outer casing, wherein: At least two connecting brackets are fixedly connected to the inner cone, and each connecting bracket is distributed circumferentially around the inner cone. The outer ends of the connecting brackets are fixedly connected to the outer casing, and the middle casing is fixedly connected to the connecting brackets. A flange is provided on the middle casing, and the flange is detachably connected to the stator of the engine by bolts. The inner end of the connecting bracket is welded to the inner cone; Each of the connecting brackets is welded to the middle casing respectively; The outer end of the connecting bracket is detachably connected to the outer casing through a screw.

2. The tail nozzle structure suitable for a double-ducted turbofan engine according to claim 1, characterized in that: The outer casing is provided with a screw seat for inserting the screw member, and the outer end of the connecting bracket is provided with a threaded hole for cooperating with the screw member.

3. The tail nozzle structure suitable for a double-ducted turbofan engine according to claim 2, characterized in that: The screw seat is welded to the outer casing.

4. The tail nozzle structure suitable for a double-ducted turbofan engine according to claim 2, characterized in that: A threaded hole seat is embedded in the connecting bracket, and a threaded hole for cooperating with the screw member is provided on the threaded hole seat.

5. The tail nozzle structure suitable for a double-ducted turbofan engine according to claim 1, characterized in that: A guide angle is arranged on the front side of the connecting bracket, and the guide angle is arranged forward.

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