Air tightness test clamp and method for annular channel of combustor diffuser

Abstract

The invention relates to the technical field of aero-engine manufacturing, in particular to an air tightness test clamp and method for an annular channel of a combustor diffuser. The clamp comprises a bottom plate and a cover plate; the bottom plate is used for supporting the diffuser; the cover plate is used for being pressed on the top face of the diffuser. A lower sealing ring is adhered to the top surface of the bottom plate; an upper sealing ring is adhered to the bottom surface of the cover plate; a stand column is installed in the center of the bottom plate, a screw section is arranged on the upper portion of the stand column, and a first nut is screwed to the screw section after the screw section extends out of a center hole of the cover plate. A plurality of studs are mounted on the bottom plate, and the upper ends of the studs penetrate through the cover plate and then are screwed with second nuts; an air tap is installed on the cover plate, and after the diffuser is assembled on the air tightness test clamp, the air tap is communicated with the annular channel of the diffuser. The clamp can seal the upper end face and the lower end face of the diffuser, and effectively detect the air tightness of the annular channel of the diffuser.

Description

Technical Field

[0001] The invention relates to the technical field of aeroengine manufacturing, and in particular to an airtightness test fixture and method for an annular channel of a combustion chamber diffuser. Background Art

[0002] The diffuser is an important component of the combustion chamber and the first component at the combustion chamber inlet. It is connected to the compressor. The compressor outlet airflow is decelerated and pressurized after passing through the diffuser annular channel. The velocity of the combustion chamber inlet airflow is reduced with minimum total pressure loss and maximum static pressure recovery, creating conditions for stable and reliable combustion in the combustion chamber. The diffuser works under high temperature and high pressure conditions, so it needs to have good mechanical properties and sealing.

[0003] Regarding the structure of the diffuser, in the prior art, for example, a patent application with publication number CN109139262A discloses a diffuser for an aircraft engine combustion chamber, wherein the diffuser is composed of an inner ring, an outer ring, and a hollow support plate. The inner ring and the outer ring together form an annular channel, and a plurality of hollow support plates divide the annular channel into a plurality of sub-channels.

[0004] Combination Figure 1 , Figure 2 As shown, the diffuser is composed of an inner ring 100, an outer ring 101 and a hollow support plate 102. The height of the hollow support plate 102 is smaller than that of the inner ring 100 and the outer ring 101. An annular channel is formed between the inner ring 100 and the outer ring 101. The hollow support plate 102 divides the annular channel into a plurality of sub-channels.

[0005] The diffuser has a complex structure and is manufactured using a casting process. The casting process has shown its advantages in manufacturing parts with complex structures, but the casting process will produce casting defects such as cracks, pores, sand holes, inclusions, etc. Casting defects will affect the mechanical properties and sealing of the diffuser. In order to ensure the quality, reliability and safety of the diffuser, it is necessary to conduct airtightness testing on the diffuser annular channel. Since the diameter of the diffuser is about For large-diameter diffusers, how to conduct airtightness tests on the annular passage is an issue that needs to be urgently addressed. Summary of the invention

[0006] The main purpose of the present invention is to provide an airtightness test fixture and method for an annular channel of a combustion chamber diffuser, aiming to solve the above technical problems.

[0007] To achieve the above-mentioned purpose, on the one hand, the present invention proposes an airtightness test fixture for the annular channel of a combustion chamber diffuser, comprising a base plate and a cover plate; the base plate is used to support the diffuser; the cover plate is used to be pressed against the top surface of the diffuser; a lower sealing ring is bonded to the top surface of the base plate; an upper sealing ring is bonded to the bottom surface of the cover plate; a column is installed at the center position of the base plate, the upper part of the column is arranged as a screw section, the screw section extends from the center hole of the cover plate and is screwed with a first nut; a plurality of studs are installed on the base plate, the upper ends of the studs pass through the cover plate and are screwed with a second nut; an air nozzle is installed on the cover plate, and when the diffuser is assembled on the airtightness test fixture, the air nozzle is communicated with the annular channel of the diffuser.

[0008] Preferably, the base plate includes an inner ring body and an outer ring body; the lower sealing ring is bonded to the top surface of the outer ring body; the inner ring body and the outer ring body are connected by eight support plates, and a first lightening hole is formed between two adjacent support plates; and a plurality of second lightening holes are evenly distributed in an annular shape on the cover plate.

[0009] Preferably, a stud mounting hole is provided on the support plate; after the lower end of the stud is screwed into the stud mounting hole, spot welding is performed, and the number of welding spots is 3 to 5.

[0010] Preferably, a column mounting hole is provided at the center of the inner ring body; an insert section and a flange plate are provided at the lower end of the column; the insert section is inserted into the column mounting hole, and the two adopt an interference fit of H7 / n6; the flange plate is against the top surface of the inner ring body, and the flange plate and the inner ring body are fastened together by a third screw.

[0011] Preferably, the middle section of the column is a sliding fit section; the central hole of the cover plate is slidingly fitted with the outer cylindrical surface of the sliding fit section.

[0012] Preferably, a first pad is arranged between the first nut and the cover plate, the first pad is mounted on the cover plate by a first screw, a U-shaped notch is arranged on the first pad, the first pad can rotate around the first screw so that the U-shaped notch on the first pad is stuck on the screw segment; the aperture of the center hole of the cover plate is larger than the outer diameter of the first nut.

[0013] Preferably, a stud through hole is provided on the cover plate, the upper end of the stud is inserted into the stud through hole, a second pad is provided between the second nut and the cover plate, the second pad is mounted on the cover plate by a second screw, a U-shaped notch is provided on the second pad, the second pad can rotate around the second screw so that the U-shaped notch on the second pad is stuck on the stud; the aperture of the stud through hole is larger than the outer diameter of the second nut.

[0014] Preferably, the lower end of the air nozzle is provided with an external thread and is screwed onto the cover plate, and a sealing gasket is provided between the air nozzle and the cover plate; the upper part of the air nozzle is provided as a connecting pipe part, the longitudinal cross-section of the outer peripheral surface of the connecting pipe part is serrated, and the outer diameter of the lower end of the connecting pipe part is larger than the outer diameter of the upper end.

[0015] On the other hand, the present invention also provides a method for testing the air tightness of an annular channel of a combustion chamber diffuser, using the above-mentioned air tightness test fixture, comprising the following steps:

[0016] S1. Turn the upper and lower end faces of the diffuser. The runout requirement for the upper and lower end faces of the diffuser is 0.05;

[0017] S2. Use a crane to lift the air tightness test fixture and diffuser into the water tank, wet them, and then lift them out;

[0018] S3. Remove the cover plate from the airtightness test fixture, wet the lower sealing ring and the upper sealing ring with cotton cloth dipped in water, and place the diffuser on the lower sealing ring of the bottom plate; then press the cover plate on the top surface of the diffuser so that the upper sealing ring covers the upper end surface of the diffuser; tighten the first nut and the second nut;

[0019] S4. Connect the air duct interface of the air tightness tester to the air nozzle;

[0020] S5. Use a crane to lift the air tightness test fixture after clamping the diffuser into the water tank of the air tightness tester, and wipe off the bubbles adsorbed on the surface of the diffuser with cotton cloth;

[0021] S6. Adjust the control valve of the air tightness tester, adjust the air supply pressure to the set value and maintain it for a period of time, and observe whether there are bubbles on the surface of the diffuser. If there are no bubbles, it is qualified, and if there are bubbles, it is unqualified.

[0022] Preferably, in step S6, the gas supply pressure setting value is The duration should be no less than 5 minutes.

[0023] Due to the adoption of the above technical solution, the beneficial effects of the present invention are as follows:

[0024] (1) By adopting the airtightness test fixture provided by the present invention, the upper and lower end surfaces of the diffuser can be sealed, and the airtightness of the diffuser annular channel can be effectively tested.

[0025] (2) The airtightness test fixture provided by the present invention has a simple structure, low manufacturing difficulty, convenient clamping and disassembly, and high detection efficiency.

[0026] (3) The airtightness test fixture provided by the present invention can be widely applied to full-ring casing parts. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0028] Figure 1 is a schematic diagram of the three-dimensional structure of the diffuser;

[0029] Figure 2 is a cross-sectional view of the diffuser;

[0030] Figure 3 A cross-sectional view of the airtightness test fixture provided by the present invention;

[0031] Figure 4 A partial top view of the bottom plate of the present invention;

[0032] Figure 5 It is a partial top view of the lower sealing ring of the present invention;

[0033] Figure 6 It is a structural schematic diagram of the upper sealing ring in the present invention;

[0034] Figure 7 is a top view of the cover plate of the present invention;

[0035] Figure 8 It is a schematic diagram of the structure of the gas nozzle in the present invention;

[0036] Fig. 9 It is a structural schematic diagram of the middle column of the present invention;

[0037] Fig.10 is a schematic diagram of the first pad or the second pad in the present invention;

[0038] Fig.11 This is a schematic structural diagram of the air tightness test fixture provided by the present invention after clamping the diffuser.

[0039] Explanation of the accompanying drawings: 1. Base plate; 1a. Inner ring body; 1b. Outer ring body; 1c. Support plate; 1d. First lightening hole; 1e. Stud mounting hole; 1f. Column mounting hole; 2. Lower sealing ring; 3. Upper sealing ring; 4. Cover plate; 4a. Stud through hole; 4b. Second lightening hole; 5. Air nozzle; 6. Sealing pad; 7. Column; 7a. Screw section; 7b. Plug-in section; 7c. Flange plate; 7d. Sliding fit section; 8. First nut; 9. First gasket; 10. Second nut; 11. Stud; 12. Second gasket; 13. Second screw; 14. Third screw; 15. First screw; 100. Inner ring; 101. Outer ring; 102. Hollow support plate. DETAILED DESCRIPTION

[0040] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only 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.

[0041] It should be noted that all directional indications in the embodiments of the present invention (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0042] In addition, the descriptions of "first", "second", etc. in the present invention are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in the field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0043] Combination Figure 1 , Figure 2 As shown, the diffuser is composed of an inner ring 100, an outer ring 101 and a hollow support plate 102. The height of the hollow support plate 102 is smaller than that of the inner ring 100 and the outer ring 101. An annular channel is formed between the inner ring 100 and the outer ring 101. The hollow support plate 102 divides the annular channel into a plurality of sub-channels.

[0044] Combination Figures 3 to 11 As shown, on the one hand, this embodiment provides an airtightness test fixture for the annular channel of a combustion chamber diffuser, comprising a base plate 1 and a cover plate 4; the base plate 1 is used to support the diffuser; the cover plate 4 is used to be pressed against the top surface of the diffuser; a lower sealing ring 2 is bonded to the top surface of the base plate 1; an upper sealing ring 3 is bonded to the bottom surface of the cover plate 4; a column 7 is installed at the center position of the base plate 1, and the upper part of the column 7 is provided with a screw segment 7a, and the screw segment 7a extends out of the center hole of the cover plate 4 and is screwed with a first nut 8; a plurality of studs 11 are installed on the base plate 1, and the upper ends of the studs 11 pass through the cover plate 4 and are screwed with a second nut 10; a gas nozzle 5 is installed on the cover plate 4, and when the diffuser is assembled on the airtightness test fixture, the gas nozzle 5 is connected to the annular channel of the diffuser.

[0045] Combination Figure 4 and Figure 7 As shown, the base plate 1 includes an inner ring body 1a and an outer ring body 1b; the lower sealing ring 2 is bonded to the top surface of the outer ring body 1b; the inner ring body 1a and the outer ring body 1b are connected by eight support plates 1c, and a first lightening hole 1d is formed between two adjacent support plates 1c; and a plurality of second lightening holes 4b are evenly distributed in a ring shape on the cover plate 4.

[0046] Combination Figure 3 and Figure 4 As shown, a stud mounting hole 1e is provided on the support plate 1c; the lower end of the stud 11 is screwed into the stud mounting hole 1e and then spot welded, and the number of welding spots is 3 to 5.

[0047] Combination Figure 3 , Figure 4 and Fig. 9 As shown, a column mounting hole 1f is provided at the center of the inner ring body 1a; a plug-in section 7b and a flange plate 7c are provided at the lower end of the column 7; the plug-in section 7b is inserted into the column mounting hole 1f, and the two adopt an interference fit of H7 / n6, that is, the plug-in section 7b will be pressed into the column mounting hole 1f during assembly to form a tight fit. ; The flange plate 7c abuts against the top surface of the inner ring body 1a, and the flange plate 7c is fastened to the inner ring body 1a by a third screw 14.

[0048] Combination Figure 4 and Fig. 9 As shown, the middle section of the column 7 is a sliding fit section 7d; the central hole of the cover plate 4 is slidingly fitted with the outer cylindrical surface of the sliding fit section 7d, and this structure can play a centering role for the cover plate 4.

[0049] Combination Figure 3 and Fig.10 As shown, a first pad 9 is provided between the first nut 8 and the cover plate 4, the first pad 9 is mounted on the cover plate 4 by a first screw 15, a U-shaped notch is provided on the first pad 9, the first pad 9 can rotate around the first screw 15, so that the U-shaped notch on the first pad 9 is stuck on the screw segment 7a; the diameter of the center hole of the cover plate 4 is larger than the outer diameter of the first nut 8. Further, a stud through hole 4a is provided on the cover plate 4, the upper end of the stud 11 is penetrated in the stud through hole 4a, a second pad 12 is provided between the second nut 10 and the cover plate 4, the second pad 12 is mounted on the cover plate 4 by a second screw 13, a U-shaped notch is provided on the second pad 12, the second pad 12 can rotate around the second screw 13, so that the U-shaped notch on the second pad 12 is stuck on the stud 11; the diameter of the stud through hole 4a is larger than the outer diameter of the second nut 10.

[0050] By adopting the above structure, when it is necessary to remove the cover plate 4 from the airtight test fixture, it is only necessary to loosen the first nut 8 and the second nut 10, and it is only necessary to rotate the first pad 9 and the second pad 12 so that the first pad 9 is separated from the screw segment 7a, and the second pad 12 is separated from the stud 11. Since the aperture of the center hole of the cover plate 4 is larger than the outer diameter of the first nut 8, and the aperture of the stud through hole 4a is larger than the outer diameter of the second nut 10, it is not necessary to remove the first nut 8 and the second nut 10, and the cover plate 4 can be removed from the airtight test fixture. Conversely, when it is necessary to lock the cover plate 4, the first pad 9 and the second pad 12 are rotated so that the U-shaped notch on the first pad 9 is stuck on the screw segment 7a, and the U-shaped notch on the second pad 12 is stuck on the stud 11, and the first nut 8 and the second nut 10 can be tightened to lock the cover plate 4.

[0051] Combination Figure 8 As shown, the lower end of the air nozzle 5 is provided with an external thread and is screwed onto the cover plate 4, and a sealing pad 6 is provided between the air nozzle 5 and the cover plate 4; the upper part of the air nozzle 5 is provided as a connecting pipe part, the longitudinal cross-section of the outer peripheral surface of the connecting pipe part is serrated, and the outer diameter φC of the lower end of the connecting pipe part is larger than the outer diameter φD of the upper end, forming a pagoda shape, so as to facilitate connection with the air duct of the air tightness tester.

[0052] On the other hand, this embodiment also provides a method for testing the air tightness of an annular channel of a combustor diffuser, using the above-mentioned air tightness test fixture, and comprising the following steps:

[0053] S1. Turn the upper end face A and lower end face B of the diffuser. The runout requirement of the upper and lower end faces of the diffuser is 0.05 to ensure the flatness of the diffuser end face and enhance the sealing between the diffuser and the upper and lower sealing rings;

[0054] S2. Use a crane to lift the air tightness test fixture and diffuser into the water tank, wet them, and then lift them out; the purpose of wetting is to use the surface tension of water between the diffuser and the upper and lower sealing rings to enhance the sealing performance;

[0055] S3, remove the cover plate 4 from the airtightness test fixture, wet the lower sealing ring 2 and the upper sealing ring 3 with cotton cloth dipped in water, and place the diffuser on the lower sealing ring 2 of the base plate 1; then press the cover plate 4 on the top surface of the diffuser so that the upper sealing ring 3 covers the upper end surface of the diffuser; tighten the first nut 8 and the second nut 10;

[0056] S4, connect the air duct interface of the air tightness tester to the air nozzle 5;

[0057] S5. Use a crane to lift the air tightness test fixture after clamping the diffuser into the water tank of the air tightness tester, and wipe off the bubbles adsorbed on the surface of the diffuser with cotton cloth;

[0058] S6. Adjust the control valve of the air tightness tester, adjust the air supply pressure to the set value and keep it for a while, and observe whether there are bubbles on the surface of the diffuser. If there are no bubbles, it is qualified, and if there are bubbles, it is unqualified. Mark the unqualified parts to facilitate the subsequent analysis of the reasons for the failure.

[0059] Specifically, in step S6, the gas supply pressure setting value is The duration should be no less than 5 minutes.

[0060] After the test, the fixture and the diffuser are taken out of the water tank by a crane, the first nut 8 and the second nut 10 are loosened, the cover plate 4 is removed, and the diffuser is taken out and dried.

[0061] The above description is only a preferred embodiment of the present invention, and does not limit the patent scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification and drawings under the inventive concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. An air tightness test fixture for a combustion chamber diffuser annular channel, characterized in that: It comprises a base plate (1) and a cover plate (4); the base plate (1) is used to support a diffuser; the cover plate (4) is used to be pressed against the top surface of the diffuser; a lower sealing ring (2) is bonded to the top surface of the base plate (1); and an upper sealing ring (3) is bonded to the bottom surface of the cover plate (4); A column (7) is installed at the center of the base plate (1), the upper part of the column (7) is provided as a screw segment (7a), the screw segment (7a) extends out from the center hole of the cover plate (4) and is screwed with a first nut (8); a plurality of studs (11) are installed on the base plate (1), the upper ends of the studs (11) pass through the cover plate (4) and are screwed with a second nut (10); An air nozzle (5) is installed on the cover plate (4); after the diffuser is assembled on the air tightness test fixture, the air nozzle (5) is connected to the annular channel of the diffuser.

2. The air tightness test fixture of the combustion chamber diffuser annular channel according to claim 1, characterized in that: The bottom plate (1) comprises an inner ring body (1a) and an outer ring body (1b); the lower sealing ring (2) is bonded to the top surface of the outer ring body (1b); the inner ring body (1a) and the outer ring body (1b) are connected via eight support plates (1c), and a first lightening hole (1d) is formed between two adjacent support plates (1c); and a plurality of second lightening holes (4b) are evenly distributed in an annular shape on the cover plate (4).

3. The air tightness test fixture of the combustion chamber diffuser annular channel according to claim 2, characterized in that: The support plate (1c) is provided with a stud mounting hole (1e); the lower end of the stud (11) is screwed into the stud mounting hole (1e) and then spot welded, with the number of welding spots being 3 to 5.

4. The air tightness test fixture for the annular channel of a combustion chamber diffuser according to claim 2, characterized in that: A column mounting hole (1f) is provided at the center of the inner ring body (1a); a plug-in section (7b) and a flange plate (7c) are provided at the lower end of the column (7); The plug-in section (7b) is inserted into the column mounting hole (1f), and the two adopt an interference fit of H7 / n6; The flange plate (7c) abuts against the top surface of the inner ring body (1a), and the flange plate (7c) and the inner ring body (1a) are fastened together by a third screw (14).

5. The air tightness test fixture for the annular channel of a combustion chamber diffuser according to claim 1, characterized in that: The middle section of the upright column (7) is a sliding fit section (7d); the central hole of the cover plate (4) is slidingly fitted with the outer cylindrical surface of the sliding fit section (7d).

6. The air tightness test fixture for the annular channel of a combustion chamber diffuser according to claim 1, characterized in that: A first pad (9) is arranged between the first nut (8) and the cover plate (4); the first pad (9) is mounted on the cover plate (4) by means of a first screw (15); a U-shaped notch is arranged on the first pad (9); the first pad (9) can rotate around the first screw (15) so that the U-shaped notch on the first pad (9) is clamped on the screw segment (7a); and the diameter of the central hole of the cover plate (4) is larger than the outer diameter of the first nut (8).

7. The air tightness test fixture for the annular channel of a combustion chamber diffuser according to claim 1, characterized in that: A stud through hole (4a) is provided on the cover plate (4), the upper end of the stud (11) is inserted into the stud through hole (4a), a second pad (12) is provided between the second nut (10) and the cover plate (4), the second pad (12) is mounted on the cover plate (4) by a second screw (13), a U-shaped notch is provided on the second pad (12), the second pad (12) can rotate around the second screw (13), so that the U-shaped notch on the second pad (12) is clamped on the stud (11); the hole diameter of the stud through hole (4a) is larger than the outer diameter of the second nut (10).

8. The air tightness test fixture for the annular channel of a combustion chamber diffuser according to claim 1, characterized in that: The lower end of the gas nozzle (5) is provided with an external thread and is screwed onto the cover plate (4), and a sealing pad (6) is provided between the gas nozzle (5) and the cover plate (4); the upper part of the gas nozzle (5) is provided as a connecting pipe part, the longitudinal cross-section of the outer peripheral surface of the connecting pipe part is serrated, and the outer diameter of the lower end of the connecting pipe part is greater than the outer diameter of the upper end.

9. A method for testing the air tightness of a combustion chamber diffuser annular channel, characterized in that: The airtightness test fixture according to any one of claims 1 to 8 is used, comprising the following steps: S1. Turn the upper and lower end faces of the diffuser. The runout requirement for the upper and lower end faces of the diffuser is 0.05; S2. Use a crane to lift the air tightness test fixture and diffuser into the water tank, wet them, and then lift them out; S3. Remove the cover plate (4) from the airtightness test fixture, wet the lower sealing ring (2) and the upper sealing ring (3) with cotton cloth dipped in water, and place the diffuser on the lower sealing ring (2) of the base plate (1); then press the cover plate (4) onto the top surface of the diffuser so that the upper sealing ring (3) covers the upper end surface of the diffuser; and tighten the first nut (8) and the second nut (10); S4, connecting the air duct interface of the air tightness tester to the air nozzle (5); S5. Use a crane to lift the air tightness test fixture after clamping the diffuser into the water tank of the air tightness tester, and wipe off the bubbles adsorbed on the surface of the diffuser with cotton cloth; S6. Adjust the control valve of the air tightness tester, adjust the air supply pressure to the set value and maintain it for a period of time, and observe whether there are bubbles on the surface of the diffuser. If there are no bubbles, it is qualified, and if there are bubbles, it is unqualified.

10. A method for testing the air tightness of a combustion chamber diffuser annular passage according to claim 9, characterized in that: In step S6, the gas supply pressure setting value is The duration should be no less than 5 minutes.

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