A method of flexible airtight sealing of a large opening of an aircraft exhaust duct

Abstract

The application belongs to the field of flexible airtight sealing, and particularly relates to a flexible airtight sealing method for a large opening of an aircraft exhaust duct. According to the profile design principle of a rigid device on the cross section of a large opening at the rear end of an exhaust duct structure determined according to the airtight sealing principle, a flexible device is arranged to perform flexible plugging of the gap. The maximum deformation of a circumference in theoretical deformation data is selected as a unified size design allowance of the rigid device and the large opening at the rear end of the exhaust duct structure. Based on the ballast value and the pressure center, a load transmission device is connected to the rigid device of the sealing device of the large opening at the rear end of the exhaust duct structure, and the internal pressurized load acting on the sealing device of the large opening at the rear end is transmitted to a test bearing device. The flexible airtight sealing of the aircraft exhaust duct structure by the flexible device can ensure the airtightness of the aircraft exhaust duct structure without being limited by geometric characteristics, and is not only suitable for conventional exhaust duct structures, but also suitable for more complex special-shaped curved structures.

Description

Technical Field

[0001] This application belongs to the field of flexible airtight seals, and specifically relates to a flexible airtight seal method for a large opening in an aircraft exhaust duct. Background Technology

[0002] In recent years, in order to catch up with similar foreign technologies and enhance the penetration capabilities of large military aircraft, China has conducted increasing research and application of engine exhaust duct structures. In practical use, the exhaust duct structure must withstand the high-temperature, high-speed airflow emitted by the engine, requiring reasonable structural strength. Ground strength testing (pressure testing) is an indispensable technical means to study and verify the rationality of the exhaust duct structure's strength design.

[0003] As a newly emerging aircraft structure in China, there is no prior ground strength test experience to draw upon. In previous pressurization tests of similar air intake structures, the large opening at the front end of the air intake structure was relatively rigid and exhibited minimal deformation. Therefore, the sealing of the large opening at the front end was typically achieved through a rigid device connected to (bonded) the opening for airtight sealing. Since the air intake structure was a straight-through structure, the rigid devices at the front and rear ends were balanced by a tie rod to counteract the internal pressurization load. However, in ground strength tests of the exhaust structure, there is an internal pressurization load, and the large opening at the rear end needs to be in a free state. This means that the airtight sealing measures at the rear opening cannot restrict the deformation of the opening. Therefore, the connection (bonded) seal used in previous air intake structure pressurization tests is not applicable. Furthermore, the exhaust duct is generally an irregularly shaped curved structure, and the load of the internal pressurization load acting on the sealing device of the large opening at the rear end cannot be counteracted by the tie rod between the sealing device and the front end.

[0004] Therefore, how to achieve a more effective seal for the exhaust duct is a problem that needs to be solved. Summary of the Invention

[0005] The purpose of this application is to provide a flexible airtight sealing method for a large opening in an aircraft exhaust duct, so as to solve the problem that it is difficult to achieve airtight sealing of a large opening at the rear end of an aircraft exhaust duct structure under pressurized load in the prior art.

[0006] The technical solution of this application is: a flexible airtight sealing method for a large opening in an aircraft exhaust duct, comprising:

[0007] Obtain structural data of the large opening at the rear end of the exhaust duct structure, and analyze and determine the airtight sealing principle of the large opening at the rear end of the exhaust duct structure under internal pressurized load.

[0008] Based on the principle of airtight sealing, the outline design principle of the rigid device on the large opening section at the rear end of the exhaust duct structure is determined. A flexible device is set between the rigid device and the large opening at the rear end of the exhaust duct structure to perform gap flexible sealing and complete sealing.

[0009] The theoretical deformation data of the large opening at the rear end of the exhaust duct structure under actual use was calculated and analyzed. The maximum circumferential deformation in the theoretical deformation data was selected as the design allowance for the unified size of the rigid device and the large opening at the rear end of the exhaust duct structure, and then the outline of the rigid device was determined.

[0010] Calculate the ballast value and pressure core of the internal pressurized load acting on the rigid and flexible devices of the large opening at the rear end of the exhaust duct structure based on the design allowance; based on the ballast value and pressure core, connect a load transfer device to the rigid device of the sealing device of the large opening at the rear end of the exhaust duct structure to transfer the load of the internal pressurized load acting on the sealing device of the large opening at the rear end to the test bearing device.

[0011] Preferably, the ballast size on the rigid and flexible devices of the large opening at the rear end of the exhaust duct structure is calculated by the pressurization load inside the exhaust duct; the pressurization load inside the exhaust duct is calculated by collecting aircraft exhaust duct temperature field data, engine thrust and exhaust duct distributed pressure under ground strength test.

[0012] The geometric center of the exhaust passage is taken as the pressure center.

[0013] Preferably, the load transfer device includes a flange and an extended bearing support; the flange and the extended bearing support are welded together as a whole, the flange is connected to a rigid device of the rear large opening sealing device, and the extended bearing support is connected to the test bearing device; the load acting on the rear large opening of the exhaust duct structure is transferred to the test bearing device through the load transfer device.

[0014] Preferably, the theoretical deformation data of the large opening at the rear end of the exhaust duct structure under internal pressurized load is obtained through finite element simulation calculation.

[0015] Preferably, the flexible device is an inflatable airbag, and the inflatable load inside the airbag is higher than the inflatable load inside the exhaust duct.

[0016] Preferably, the entire structure of the exhaust duct is pressurized during the ground strength test. Under the action of the internal pressurization load, the large opening at the rear end of the exhaust duct structure will deform.

[0017] The flexible airtight sealing method for large openings in aircraft exhaust ducts proposed in this application uses a flexible device to achieve flexible airtight sealing of the aircraft exhaust duct structure. It can ensure the airtightness of the aircraft exhaust duct structure without being limited by geometric features. It is not only applicable to conventional exhaust duct structures, but also to more complex irregular curved structures, and has great application prospects. Attached Figure Description

[0018] To more clearly illustrate the technical solutions provided in this application, the accompanying drawings will be briefly described below. Obviously, the drawings described below are merely some embodiments of this application.

[0019] Figure 1 This is a schematic diagram of the airtight seal of the aircraft exhaust duct structure in this application;

[0020] Figure 2 This is a schematic diagram of the overall seal combining the rigid and flexible devices of this application;

[0021] Figure 3 This is a schematic diagram of the overall structure of this application.

[0022] 1. Large opening at the rear end of the exhaust duct structure; 2. Flexible device; 3. Rigid device; 4. Load transfer device; 5. Test bearing device. Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] A flexible, airtight sealing method for a large opening in an aircraft exhaust duct, wherein the rear end of the aircraft exhaust duct structure is a completely open opening, such as... Figure 1 As shown, the entire exhaust duct structure needs to be pressurized during ground strength testing. Under the internal pressurization load, the large opening at the rear end of the exhaust duct structure will deform. Airtight sealing of the large opening at the rear end of the exhaust duct structure under pressurization load cannot limit its deformation under the internal pressurization load.

[0025] Based on the above, a combination of rigid and flexible devices is used for airtight sealing.

[0026] Specifically, the steps include the following:

[0027] Step S100: Obtain structural data of the large opening 1 at the rear end of the exhaust duct structure, and analyze and determine the airtight sealing principle of the large opening 1 at the rear end of the exhaust duct structure under internal pressurized load.

[0028] Preferably, the entire exhaust duct structure needs to be pressurized during the ground strength test. Under the action of the internal pressurization load, the large opening 1 at the rear end of the exhaust duct structure will deform. Airtight sealing of the large opening 1 at the rear end of the exhaust duct structure under pressurization load cannot limit the deformation of the large opening at the rear end under the internal pressurization load.

[0029] Step S200, as follows Figure 2Based on the principle of airtight sealing, the outline design principle of the rigid device on the cross section of the large opening 1 at the rear end of the exhaust duct structure is determined. A flexible device is set between the rigid device and the large opening 1 at the rear end of the exhaust duct structure to perform gap flexible sealing until complete sealing.

[0030] Preferably, the flexible device 2 is an inflatable airbag, with the inflation load inside the airbag being slightly higher than the inflation load inside the exhaust duct. The high-pressure gas inside the exhaust duct is blocked by the inflatable airbag, thereby achieving an airtight seal.

[0031] The large opening 1 at the rear end of the exhaust duct structure deforms under the internal pressurized load and is released by squeezing the pressurized airbag.

[0032] Step S300: Calculate and analyze the theoretical deformation data of the large opening 1 at the rear end of the exhaust duct structure under actual use, and select the maximum circumferential deformation in the theoretical deformation data as the unified size design allowance for the rigid device 3 and the large opening 1 at the rear end of the exhaust duct structure.

[0033] Preferably, the theoretical deformation data of the large opening 1 at the rear end of the exhaust duct structure under internal pressurization load is obtained through finite element simulation calculation.

[0034] While selecting the maximum circumferential deformation as the design allowance for the unified size of the rigid device 3 and the large opening 1 at the rear end of the exhaust duct structure, a certain safety margin is added to the maximum circumferential deformation to improve safety performance.

[0035] Step S400, as follows Figure 3 Based on the design allowance, the ballast value and pressure core of the internal pressurization load acting on the rigid device 3 and flexible device 2 of the large opening 1 at the rear end of the exhaust duct structure are calculated. Based on the ballast value and pressure core, the load transfer device 4 is connected to the rigid device 3 of the large opening at the rear end of the exhaust duct structure to transfer the load of the internal pressurization load acting on the sealing device of the large opening at the rear end to the test bearing device 5.

[0036] Preferably, the load transfer device 4 includes a flange and a lead-out bearing support; the flange and the lead-out bearing support are welded together as a whole, the flange is connected to a rigid device at the rear end of the exhaust duct structure's large opening 1, and the lead-out bearing support is connected to the test bearing device; the load acting on the rear end of the exhaust duct structure's large opening 1 is transferred to the test bearing device 5 through the load transfer device 4. The load transfer device 4 can enclose the load center on the rear end of the exhaust duct structure's large opening 1 and has sufficient strength, stiffness, and stability.

[0037] Preferably, the load on the large opening section 1 at the rear end of the exhaust duct structure is calculated using the pressurized load within the exhaust duct; the pressurized load within the exhaust duct is calculated by collecting aircraft exhaust duct temperature field data, engine thrust, and exhaust duct distributed pressure data under ground strength testing. The geometric center of the exhaust duct is taken as the pressure center.

[0038] In summary, this application utilizes a complete set of devices based on flexible device 2 to achieve flexible airtight sealing of the aircraft exhaust duct structure. This ensures the airtightness of the aircraft exhaust duct structure without being limited by geometric features. It is applicable not only to conventional exhaust duct structures but also to more complex irregular curved structures, and has great application prospects.

[0039] Finally, it should be noted that the accompanying drawings of the embodiments disclosed in this invention only involve the structures involved in the embodiments disclosed in this invention. Other structures can refer to the general design. In the absence of conflict, the same embodiment and different embodiments of this invention can be combined with each other.

[0040] In conclusion, the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A flexible, airtight sealing method for a large opening in an aircraft exhaust duct, characterized in that, include: Obtain structural data of the large opening (1) at the rear end of the exhaust duct structure, and analyze and determine the airtight sealing principle of the large opening (1) at the rear end of the exhaust duct structure under internal pressurized load. Based on the principle of airtight sealing, the outline design principle of the rigid device (3) on the cross section of the large opening (1) at the rear end of the exhaust duct structure is determined. A flexible device (2) is set between the rigid device (3) and the large opening (1) at the rear end of the exhaust duct structure to perform flexible sealing of the gap and complete sealing. The theoretical deformation data of the large opening (1) at the rear end of the exhaust duct structure is calculated and analyzed under actual use. The maximum deformation around the perimeter in the theoretical deformation data is selected as the design allowance for the unified size of the rigid device (3) and the large opening (1) at the rear end of the exhaust duct structure, and then the outline of the rigid device (3) is determined. Calculate the ballast value and pressure core of the internal pressurization load acting on the rigid device (3) and flexible device (2) of the large opening (1) at the rear end of the exhaust duct structure according to the design allowance; based on the ballast value and pressure core, connect the load transfer device (4) to the rigid device (3) of the sealing device of the large opening at the rear end of the exhaust duct structure to transfer the load of the internal pressurization load acting on the sealing device of the large opening at the rear end to the test bearing device (5).

2. The flexible airtight sealing method for a large opening in an aircraft exhaust duct as described in claim 1, characterized in that: The ballast size on the rigid device (3) and flexible device (2) of the large opening (1) at the rear end of the exhaust duct structure is calculated by the pressurization load in the exhaust duct; the pressurization load in the exhaust duct is calculated by collecting the temperature field data of the aircraft exhaust duct, engine thrust and exhaust duct distribution pressure under ground strength test. The geometric center of the exhaust passage is taken as the pressure center.

3. The flexible airtight sealing method for a large opening in an aircraft exhaust duct as described in claim 1, characterized in that: The load transfer device (4) includes a flange and an outgoing bearing support; the flange and the outgoing bearing support are welded together as a whole, the flange is connected to the rigid device (3) of the rear large opening sealing device, and the outgoing bearing support is connected to the test bearing device (5); the load acting on the rear large opening (1) of the exhaust duct structure is transferred to the test bearing device (5) through the load transfer device (4).

4. The flexible airtight sealing method for a large opening in an aircraft exhaust duct as described in claim 1, characterized in that: The theoretical deformation data of the large opening (1) at the rear end of the exhaust duct structure under internal pressurization load were obtained by finite element simulation calculation.

5. The flexible airtight sealing method for a large opening in an aircraft exhaust duct as described in claim 1, characterized in that: The flexible device (2) is an inflatable airbag, and the inflatable load inside the inflatable airbag is higher than the inflatable load inside the exhaust channel.

6. The flexible airtight sealing method for a large opening in an aircraft exhaust duct as described in claim 1, characterized in that: In the ground strength test, the entire structure of the exhaust duct is pressurized. Under the action of the internal pressurization load, the large opening (1) at the rear end of the exhaust duct structure will deform.

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