Aircraft covering cap heat sealing performance testing method for realizing hot pressing environment simulation

Abstract

The invention belongs to the field of thermal tests of hypersonic aircrafts, and particularly relates to an aircraft covering cap thermal sealing performance testing method for realizing hot-pressing environment simulation. The method comprises the following steps: step 1, designing a special test tool; 2, designing a test piece; 3, assembling the test piece and a special test tool; 4, building a hot-pressing environment simulation system; and 5, based on a hot-pressing environment simulation system, carrying out a heat sealing performance test on the test piece. The aircraft covering cap heat sealing performance test method for realizing the hot-pressing environment simulation is suitable for the heat sealing performance test of the aircraft covering cap part, can realize the independent simulation of pneumatic heating and internal and external pressure difference environments in the heat sealing performance test, can carry out the accurate control of the hot-pressing environment in the test, and improves the test efficiency. Therefore, the heat sealing performance test accuracy of the covering cap part of the aircraft is improved. And meanwhile, the test cost is low, and the method can be used for repeatedly testing the heat sealing performance.

Description

Technical Field

[0001] The present application belongs to the field of hypersonic aircraft thermal testing, and in particular, relates to a method for testing the thermal sealing performance of an aircraft cover by simulating a thermal pressure environment. Background Art

[0002] There are often flaps of different sizes on the surface of aircraft. During flight, hot external gas may enter the aircraft through the gaps in the flaps, causing changes in the internal ambient temperature and pressure, affecting the normal operation of the equipment in the cabin. To avoid this problem, it is necessary to design a heat seal at the flap and conduct tests to assess the heat seal performance of the flap.

[0003] During the test, the flap part needs to simulate the aerodynamic heating and internal and external pressure difference environment during flight. At present, the thermal pressure environment during flight is often simulated by flowing high-temperature and high-pressure gas over the surface of the test piece. The advantage of this method is that the influence of high-temperature gas on the gap can be considered. The disadvantage is that the thermal pressure environment is difficult to control and the test cost is high, which makes it difficult to meet the needs of accurate simulation and repeated testing of the thermal pressure environment.

[0004] Therefore, it is desired to have a technical solution to overcome or at least alleviate at least one of the above-mentioned defects of the prior art. Summary of the invention

[0005] The purpose of the present application is to provide a method for testing the thermal sealing performance of an aircraft cover by simulating a thermal pressure environment, so as to solve at least one problem existing in the prior art.

[0006] The technical solution of this application is:

[0007] A method for testing the thermal sealing performance of an aircraft cover by simulating a thermal pressure environment, comprising:

[0008] Step 1: Design special test tooling;

[0009] Step 2: Design the test piece;

[0010] Step 3: Assemble the test piece with the special test tooling;

[0011] Step 4: Build a thermal pressure environment simulation system;

[0012] Step 5: Conduct heat sealing performance test on the test piece based on the hot pressure environment simulation system.

[0013] In at least one embodiment of the present application, in step 1, a dedicated test tool design is performed, including:

[0014] S11. Design the load-bearing structure of special test equipment;

[0015] S12. Design the thermal insulation structure of special test equipment;

[0016] S13. Design the connection structure of special test tooling;

[0017] S14. The special test tooling is processed according to the load-bearing structure, heat insulation structure and connection structure of the special test tooling.

[0018] In at least one embodiment of the present application, in S11, a load-bearing structure design of a special test fixture is performed, and the load-bearing structure of the special test fixture includes:

[0019] The steel shell is a square box-shaped body with an opening at the upper end. An outer flange is arranged at the upper end opening. A sealing groove for installing a sealing rubber ring is opened on the outer flange 10 mm away from the inner surface of the steel shell. A plurality of special test tooling bolt holes for connecting with the test piece are opened along the circumference of the outer flange.

[0020] In at least one embodiment of the present application, in S12, a thermal insulation structure design of a special test tool is performed, and the thermal insulation structure of the special test tool includes:

[0021] A special test tooling heat insulation layer is laid on the inner wall surface of the steel shell.

[0022] In at least one embodiment of the present application, in S13, designing a connection structure of a special test tool includes:

[0023] Design the number, material and screw diameter of the bolts used to connect the special test fixture and the test piece according to the maximum shear force;

[0024] In a single direction parallel to the outer flange, the total shear force F existing after the temperature of the special test fixture and the test piece is increased is:

[0025]

[0026] Among them, E 1 is the elastic modulus of the test specimen skin material, E 2 is the elastic modulus of the steel shell, α 1 is the thermal expansion coefficient of the test specimen skin material, α 2 is the thermal expansion coefficient of the steel shell, ΔT is the maximum temperature rise during the test;

[0027] For the special test fixture and test piece with N number of bolt holes on one side, the bolts at the corners are subject to the largest shear force, and the maximum shear force F Bmax for:

[0028]

[0029] To avoid bolt failure, the maximum shear force F on the corner bolts is Bmax satisfy:

[0030]

[0031] Where D is the screw diameter, σ s is the yield strength of the bolt material.

[0032] In at least one embodiment of the present application, in step 2, a test piece design is performed, and the test piece includes:

[0033] A mouth cover, wherein the inner surface of the mouth cover is paved with a test piece heat insulation layer, and the outer surface is provided with a skin, wherein the skin extends out of the mouth cover body to form a connecting portion, and the connecting portion is provided with a plurality of test piece bolt holes for connecting with a special test fixture along the circumferential direction.

[0034] In at least one embodiment of the present application, in step three, assembling the test piece with a dedicated test tool includes:

[0035] Install the sealing rubber ring in the sealing groove of the special test fixture;

[0036] Align the bolt holes on the test piece and the special test fixture, and assemble them with bolts. After assembly, a closed cavity is formed between the test piece and the special test fixture.

[0037] In at least one embodiment of the present application, in step 4, building a thermal pressure environment simulation system includes:

[0038] Install the air inlet valve and the air extraction valve on the special test fixture, and connect the air extraction valve to the air extraction device;

[0039] Arrange temperature measuring points and pressure measuring points on the special test fixture, and connect the measuring lines of the temperature measuring points and pressure measuring points with the control system;

[0040] A radiation heating device is hoisted directly above the test piece;

[0041] Connect the control circuit of the control system to the air extraction device and the radiation heating device respectively;

[0042] The test piece and the sides of the radiation heating device are enclosed by thermal insulation felt, so that a closed cavity is approximately formed between the test piece and the radiation heating device, creating a high-temperature gas environment on the surface of the test piece during the test.

[0043] In at least one embodiment of the present application, in step 5, a heat sealing performance test is performed on the test piece based on a heat pressure environment simulation system, including:

[0044] S51, close the air inlet valve, open the air extraction valve, start the air extraction device, gradually reduce the air pressure level inside the closed cavity according to the test requirements, stop exhausting after reaching a stable state, and close the air extraction valve;

[0045] S52, start the radiation heating device, simulate the aerodynamic thermal environment on the surface of the test piece according to the test requirements, and record the air pressure and temperature data inside the closed cavity;

[0046] S53. After the test loading is completed, the radiation heating device is turned off, the air inlet valve is opened, and the test is terminated after the air pressure inside the closed cavity reaches 1 atm.

[0047] The invention has at least the following beneficial technical effects:

[0048] The aircraft flap thermal sealing performance testing method realizing thermal pressure environment simulation of the present application is suitable for the thermal sealing performance testing of the aircraft flap part, and can realize independent simulation of aerodynamic heating and internal and external pressure difference environment in the thermal sealing performance testing, and can accurately control the thermal pressure environment during the test, thereby improving the accuracy of the thermal sealing performance testing of the aircraft flap part; at the same time, the test cost is low, and it can be used to carry out repeated thermal sealing performance testing. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 It is a schematic diagram of a special test tooling for one embodiment of the present application;

[0050] Figure 2 is a schematic diagram of a test piece according to an embodiment of the present application;

[0051] Figure 3 It is a schematic diagram of a thermal pressure environment simulation system according to one embodiment of the present application.

[0052] in:

[0053] 1-Steel shell; 2-Special test fixture insulation layer; 3-Sealing groove; 4-Special test fixture bolt hole; 5-Cover; 6-Test piece insulation layer; 7-Skin; 8-Test piece bolt hole. DETAILED DESCRIPTION

[0054] In order to make the purpose, technical scheme and advantages of the implementation of this application clearer, the technical scheme in the embodiment of this application will be described in more detail below in conjunction with the drawings in the embodiment of this application. In the drawings, the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions. The described embodiments are part of the embodiments of this application, not all of them. The embodiments described below with reference to the drawings are exemplary and are intended to be used to explain this application, and should not be construed as limitations on this application. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application. The embodiments of this application are described in detail below in conjunction with the drawings.

[0055] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the scope of protection of the present application.

[0056] The following is combined with Figures 1 to 3 This application is described in further detail.

[0057] The present application provides a method for testing the thermal sealing performance of an aircraft cover by simulating a thermal pressure environment, comprising the following steps:

[0058] Step 1: Design special test tooling;

[0059] Step 2: Design the test piece;

[0060] Step 3: Assemble the test piece with the special test tooling;

[0061] Step 4: Build a thermal pressure environment simulation system;

[0062] Step 5: Conduct heat sealing performance test on the test piece based on the hot pressure environment simulation system.

[0063] The aircraft cover thermal sealing performance test method for realizing thermal pressure environment simulation of the present application, in step 1, a special test tool design is performed, including:

[0064] S11. Design the load-bearing structure of special test equipment;

[0065] S12. Design the thermal insulation structure of special test equipment;

[0066] S13. Design the connection structure of special test tooling;

[0067] S14. The special test tooling is processed according to the load-bearing structure, heat insulation structure and connection structure of the special test tooling.

[0068] First, in S11, the load-bearing structure design of the special test tooling is carried out, such as Figure 1 As shown, the load-bearing structure of the special test fixture includes: a steel shell 1, which is a square box-shaped body with an opening at the upper end, and an outer flange is provided at the upper end opening. A sealing groove 3 for installing a sealing rubber ring is opened at a distance of 10 mm from the inner surface of the steel shell 1 on the outer flange, and a plurality of special test fixture bolt holes 4 for connecting with the test piece are opened along the circumference of the outer flange.

[0069] Secondly, in S12, the insulation structure of the special test fixture is designed. The insulation structure of the special test fixture includes: a special test fixture insulation layer 2, which is laid on the inner wall surface of the steel shell 1. In order to accurately evaluate the impact of the thermal sealing performance of the cover test piece on the cabin environment, an aerogel insulation layer with a thickness of d is laid on the inner wall surface of the special test fixture. 3 Normally it should be no less than 5mm.

[0070] Furthermore, the special test fixture is connected to the test piece by four-side bolts. During the test, the deformation of the steel shell 1 and the skin 7 after heating is different, causing the bolts to bear a certain shear force. In S13, the connection structure design of the special test fixture is carried out, including:

[0071] To avoid failure of bolts during testing, the number, material and screw diameter of bolts used to connect the special test fixture and the test piece are designed according to the maximum shear force;

[0072] In a single direction parallel to the outer flange, the total shear force F existing after the temperature of the special test fixture and the test piece is increased is:

[0073]

[0074] Among them, E 1 is the elastic modulus of the test specimen skin material, E 2 is the elastic modulus of the steel shell, α 1 is the thermal expansion coefficient of the test specimen skin material, α 2 is the thermal expansion coefficient of the steel shell, ΔT is the maximum temperature rise during the test;

[0075] For the special test fixture and test piece with N number of bolt holes on one side, the bolts at the corners are subject to the largest shear force, and the maximum shear force F Bmax for:

[0076]

[0077] To avoid bolt failure, the maximum shear force F on the corner bolts is Bmax satisfy:

[0078]

[0079] Where D is the screw diameter, σ s is the yield strength of the bolt material.

[0080] The invention relates to a method for testing the thermal sealing performance of an aircraft cover by simulating a thermal pressure environment. In step 2, a test piece is designed, such as Figure 2 As shown, the test piece includes: a mouth cover 5, the inner surface of which is paved with a test piece insulation layer 6, and the outer surface is provided with a skin 7, the skin 7 extends part of the main body of the outlet cover 5 to form a connecting portion, and the connecting portion is circumferentially provided with a plurality of test piece bolt holes 8 for connecting with a special test fixture.

[0081] It is understandable that the dimensions of the steel housing 1 and the test piece match each other. In this embodiment, the side length of the heat insulation layer 6 of the test piece is a 1 , the side length of skin 7 is b 1 The side length a of the upper opening of the steel shell 1 2 =a 1 , the length of the outer edge b 2 =b 1 The height h of the steel shell 1 is determined by the size of the internal cabin where the aircraft cover is installed. The thickness d of the steel shell 1 is 2 The maximum pressure difference between the inside and outside ΔP and the side length a of the opening 2 Determined by the shell material strength, it should usually be no less than the thickness d of the test piece skin 7 1 .

[0082] The aircraft cover thermal sealing performance test method for realizing thermal pressure environment simulation of the present application, in step 3, assembling the test piece with the special test tooling, includes:

[0083] Install the sealing rubber ring in the sealing groove 3 of the special test fixture;

[0084] Align the bolt holes on the test piece and the special test fixture, and assemble them with bolts. After assembly, a closed cavity is formed between the test piece and the special test fixture.

[0085] In the present invention, the aircraft cover thermal sealing performance test method for realizing thermal pressure environment simulation is as follows: in step 4, a thermal pressure environment simulation system is built on the basis of the assembled test piece and the special test tooling. Figure 3As shown, an air inlet valve and an air exhaust valve are installed on a special test fixture, and the air exhaust valve is connected to the air exhaust device; temperature measuring points and pressure measuring points are arranged on the special test fixture, and the measurement lines of the temperature measuring points and the pressure measuring points are connected to the control system; a radiation heating device is hoisted directly above the test piece; the control lines of the control system are connected to the air exhaust device and the radiation heating device respectively; the sides of the test piece and the radiation heating device are enclosed by thermal insulation felt, so that a closed cavity is approximately formed between the test piece and the radiation heating device, and a high-temperature gas environment is created on the surface of the test piece during the test.

[0086] Finally, in step 5, the thermal sealing performance test of the test piece is carried out based on the thermal pressure environment simulation system, including:

[0087] S51, close the air inlet valve, open the air extraction valve, start the air extraction device, gradually reduce the air pressure level inside the closed cavity according to the test requirements, stop exhausting after reaching a stable state, and close the air extraction valve;

[0088] S52, start the radiation heating device, simulate the aerodynamic thermal environment on the surface of the test piece according to the test requirements, and record the air pressure and temperature data inside the closed cavity;

[0089] S53. After the test loading is completed, the radiation heating device is turned off, the air inlet valve is opened, and the test is terminated after the air pressure inside the closed cavity reaches 1 atm.

[0090] The invention discloses a method for testing the thermal sealing performance of an aircraft mouth cover by simulating a thermal pressure environment. The method comprises the following steps: installing a flat-plate mouth cover test piece on a special test fixture. The special test fixture and the test piece form a closed cavity. The pressure difference between the inside and outside of the mouth cover 5 during flight is simulated by reducing the air pressure inside the closed cavity. Meanwhile, a radiation heating device is used to simulate the aerodynamic heating environment on the outer surface of the test piece. Thus, an independent and accurate simulation of the thermal pressure environment is achieved. The test cost is low, and the requirements for accurate simulation and repeated testing of the thermal pressure environment in thermal tests of hypersonic aircraft can be met.

[0091] The aircraft cover thermal sealing performance testing method for realizing thermal pressure environment simulation of the present application has the following beneficial effects:

[0092] a. It can realize the independent and accurate simulation of pneumatic heating and internal and external pressure difference environment of flat-type cover test pieces, with low cost, and can be used for repeated testing of thermal sealing performance;

[0093] b. Design the bolt connection of the special test fixture. The number, size, material, etc. of the bolts can be determined by the loading temperature and material type to ensure that the bolt stress level is within a reasonable range during the test;

[0094] c. Design the overall dimensions of the special test tooling for the flat-type cover, and simulate the cabin environment of the aircraft cover;

[0095] d. Provides a thermal sealing performance test process for a hot-pressurized environment simulation system, which can be used to evaluate thermal sealing performance based on cabin temperature and pressure results.

[0096] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A method for testing the thermal sealing performance of aircraft flaps by simulating a thermal pressure environment, characterized in that: include: Step 1: Design special test tooling; Step 2: Design the test piece; Step 3: Assemble the test piece with the special test tooling; Step 4: Build a thermal pressure environment simulation system; Step 5: Based on the hot pressure environment simulation system, conduct heat sealing performance test on the test piece.

2. The method for testing the thermal sealing performance of aircraft flaps by simulating a thermal pressure environment according to claim 1, characterized in that: In step one, a special test tool design is carried out, including: S11. Design the load-bearing structure of special test equipment; S12. Design the thermal insulation structure of special test equipment; S13. Design the connection structure of special test tooling; S14. The special test tooling is processed according to the load-bearing structure, heat insulation structure and connection structure of the special test tooling.

3. The method for testing the thermal sealing performance of aircraft flaps by simulating a thermal pressure environment according to claim 2, characterized in that: In S11, the load-bearing structure design of the special test fixture is carried out. The load-bearing structure of the special test fixture includes: A steel shell (1) is a square box-shaped body with an opening at the upper end, an outer flange is provided at the upper end opening, a sealing groove (3) for installing a sealing rubber ring is provided on the outer flange 10 mm away from the inner surface of the steel shell (1), and a plurality of special test tool bolt holes (4) for connecting with the test piece are provided along the circumference of the outer flange.

4. The method for testing the thermal sealing performance of aircraft flaps by simulating a thermal pressure environment according to claim 3, characterized in that: In S12, the thermal insulation structure design of the special test fixture is carried out. The thermal insulation structure of the special test fixture includes: A special test tool heat insulation layer (2), wherein the special test tool heat insulation layer (2) is laid on the inner wall surface of the steel shell (1).

5. The method for testing the thermal sealing performance of aircraft flaps by simulating a thermal pressure environment according to claim 4, characterized in that: In S13, the connection structure design of the special test fixture is carried out, including: Design the number, material and screw diameter of the bolts used to connect the special test fixture and the test piece according to the maximum shear force; In a single direction parallel to the outer flange, the total shear force F existing after the special test fixture and the test piece are heated is: Wherein, E1 is the elastic modulus of the test piece skin material, E2 is the elastic modulus of the steel shell, α1 is the thermal expansion coefficient of the test piece skin material, α2 is the thermal expansion coefficient of the steel shell, and ΔT is the maximum temperature rise during the test; For the special test fixture and test piece with N number of bolt holes on one side, the bolts at the corners are subject to the largest shear force, and the maximum shear force F Bmax for: To avoid bolt failure, the maximum shear force F on the corner bolts is Bmax satisfy: Where D is the screw diameter, σ s is the yield strength of the bolt material.

6. The method for testing the thermal sealing performance of aircraft flaps by simulating a thermal pressure environment according to claim 5, characterized in that: In step 2, a test piece is designed, and the test piece includes: A mouth cover (5), wherein the inner surface of the mouth cover (5) is paved with a test piece heat insulation layer (6), and the outer surface is provided with a skin (7), wherein the skin (7) extends out of the main body of the mouth cover (5) to form a connecting portion, and the connecting portion is provided with a plurality of test piece bolt holes (8) for connecting with a special test fixture along the circumferential direction.

7. The method for testing the thermal sealing performance of aircraft flaps by simulating a thermal pressure environment according to claim 6, characterized in that: In step three, the test piece is assembled with a special test fixture, including: Installing a sealing rubber ring in the sealing groove (3) of the special test fixture; Align the bolt holes on the test piece and the special test fixture, and assemble them with bolts. After assembly, a closed cavity is formed between the test piece and the special test fixture.

8. The method for testing the thermal sealing performance of aircraft flaps by simulating a thermal pressure environment according to claim 7, characterized in that: In step 4, a thermal pressure environment simulation system is built, including: Install the air inlet valve and the air extraction valve on the special test fixture, and connect the air extraction valve to the air extraction device; Arrange temperature measuring points and pressure measuring points on the special test fixture, and connect the measuring lines of the temperature measuring points and pressure measuring points with the control system; A radiation heating device is hoisted directly above the test piece; Connect the control circuit of the control system to the air extraction device and the radiation heating device respectively; The test piece and the sides of the radiation heating device are enclosed by thermal insulation felt, so that a closed cavity is approximately formed between the test piece and the radiation heating device, creating a high-temperature gas environment on the surface of the test piece during the test.

9. The method for testing the thermal sealing performance of aircraft flaps by simulating a thermal pressure environment according to claim 8, characterized in that: In step 5, based on the hot pressure environment simulation system, the test piece is subjected to a heat sealing performance test, including: S51, close the air inlet valve, open the air extraction valve, start the air extraction device, gradually reduce the air pressure level inside the closed cavity according to the test requirements, stop exhausting after reaching a stable state, and close the air extraction valve; S52, start the radiation heating device, simulate the aerodynamic thermal environment on the surface of the test piece according to the test requirements, and record the air pressure and temperature data inside the closed cavity; S53. After the test loading is completed, the radiation heating device is turned off, the air inlet valve is opened, and the test is terminated after the air pressure inside the closed cavity reaches 1 atm.

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