A test fixture and method for the airtightness of the annular channel of a combustion chamber diffuser.

Abstract

This invention relates to the field of aero-engine manufacturing technology, and more particularly to a gas tightness test fixture and method for the annular channel of a combustion chamber diffuser. The fixture includes a base plate and a cover plate; the base plate supports the diffuser; the cover plate is used to press 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 of the base plate, the upper part of which is configured as a screw section, extending from the center hole of the cover plate and screwed with a first nut; multiple studs are installed on the base plate, the upper ends of which pass through the cover plate and are screwed with second nuts; a nozzle is installed on the cover plate, and when the diffuser is assembled in the gas tightness test fixture, the nozzle is connected to the annular channel of the diffuser. This fixture can seal the upper and lower end faces of the diffuser, effectively testing the gas tightness of the diffuser's annular channel.

Description

Technical Field

[0001] This invention relates to the field of aero-engine manufacturing technology, and in particular to a test fixture and method for the airtightness of the annular channel of a combustion chamber diffuser. Background Technology

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

[0003] Regarding the structure of diffusers, existing technology, such as patent application CN109139262A, discloses a diffuser for an aero-engine combustion chamber. The diffuser consists of an inner ring, an outer ring, and hollow support plates. The inner and outer rings together form an annular channel, and multiple hollow support plates divide the annular channel into multiple sub-channels.

[0004] Combination Figure 1 , Figure 2 As shown, the diffuser consists of an inner ring 100, an outer ring 101, and a hollow support plate 102. The height of the hollow support plate 102 is less than the height 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 multiple sub-channels.

[0005] The diffuser has a complex structure and is manufactured using a casting process. While casting is advantageous for manufacturing complex parts, it can produce defects such as cracks, porosity, sand holes, and inclusions. These defects can affect the diffuser's mechanical properties and sealing performance. To ensure the diffuser's quality, reliability, and safety, airtightness testing of the diffuser's annular channel is necessary. Since the diffuser's diameter is approximately... For large-diameter diffusers, how to conduct airtightness tests on the annular channel is a problem that urgently needs to be solved. Summary of the Invention

[0006] The main objective of this invention is to provide a test fixture and method for the airtightness of the annular channel of the combustion chamber diffuser, in order to solve the above-mentioned technical problems.

[0007] To achieve the above objectives, on the one hand, the present invention proposes a gas tightness 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 press 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 of the base plate, the upper part of the column is configured as a screw section, the screw section extends from the center hole of the cover plate and is screwed with a first nut; multiple 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; a nozzle is installed on the cover plate, and when the diffuser is assembled in the gas tightness test fixture, the nozzle is connected to the annular channel of the diffuser.

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

[0009] Preferably, the support plate is provided with stud mounting holes; after the lower end of the stud is screwed into the stud mounting hole, it is spot welded, and the number of weld points is 3 to 5.

[0010] Preferably, a column mounting hole is provided at the center of the inner ring body; a plug section and a flange plate are provided at the lower end of the column; the plug section is inserted into the column mounting hole, and the two adopt an interference fit of H7 / n6; the flange plate abuts 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 in sliding fit with the outer cylindrical surface of the sliding fit section.

[0012] Preferably, a first washer is provided between the first nut and the cover plate. The first washer is mounted on the cover plate by a first screw. A U-shaped notch is provided on the first washer. The first washer can rotate around the first screw, so that the U-shaped notch on the first washer is engaged with the screw section. The diameter of the central 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 passes through the stud through hole, a second washer is provided between the second nut and the cover plate, the second washer is installed on the cover plate by a second screw, a U-shaped notch is provided on the second washer, the second washer can rotate around the second screw, so that the U-shaped notch on the second washer is engaged with the stud; the diameter 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 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, the longitudinal section of the outer peripheral surface of the connecting pipe is sawtooth-shaped, and the outer diameter of the lower end of the connecting pipe is larger than the outer diameter of the upper end.

[0015] On the other hand, the present invention also proposes a method for testing the airtightness of the annular channel of the combustion chamber diffuser, using the above-mentioned airtightness test fixture, including the following steps:

[0016] S1. Machin the upper and lower end faces of the diffuser. The runout of the upper and lower end faces of the diffuser should be 0.05.

[0017] S2. Use a crane to lift the airtightness test fixture and diffuser into the water tank for wetting, and then lift them out.

[0018] S3. Remove the cover plate from the airtightness test fixture, wet the lower and upper sealing rings with a cotton cloth dipped in water, place the diffuser on the lower sealing ring of the base plate; then press the cover plate onto 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 air bubbles adsorbed on the surface of the diffuser with a cotton cloth.

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

[0022] Preferably, in step S6, the gas supply pressure setting value is... The duration shall 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 using the airtightness test fixture provided by the present invention, the upper and lower end faces 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 testing efficiency.

[0026] (3) The airtightness test fixture provided by the present invention can be extended to the whole ring casing type parts. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

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

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

[0030] Figure 3 This is a cross-sectional view of the airtightness testing fixture provided by the present invention;

[0031] Figure 4 This is a partial top view of the base plate in this invention;

[0032] Figure 5 This is a partial top view of the lower sealing ring in this invention;

[0033] Figure 6 This is a schematic diagram of the upper sealing ring in this invention;

[0034] Figure 7 This is a top view of the cover plate in this invention;

[0035] Figure 8 This is a schematic diagram of the air nozzle structure in this invention;

[0036] Figure 9 This is a schematic diagram of the structure of the column in this invention;

[0037] Figure 10 This is a schematic diagram of the first pad or the second pad in this invention;

[0038] Figure 11 This is a schematic diagram of the structure of the airtightness test fixture provided by the present invention after clamping the diffuser.

[0039] Explanation of reference numerals: 1. Base plate; 1a. Inner ring; 1b. Outer ring; 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 gasket; 7. Column; 7a. Screw section; 7b. Insertion section; 7c. Flange plate; 7d. Sliding fit section; 8. First nut; 9. First washer; 10. Second nut; 11. Stud; 12. Second washer; 13. Second screw; 14. Third screw; 15. First screw; 100. Inner ring; 101. Outer ring; 102. Hollow support plate. Detailed Implementation

[0040] 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 a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

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

[0042] Furthermore, the use of terms such as "first" and "second" in this invention is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature. Additionally, the technical solutions of the various embodiments can be combined with each other, but only on the basis of being achievable by those skilled in the art. When the combination of technical solutions is contradictory or impossible to implement, such a combination of technical solutions should be considered non-existent and not within the scope of protection claimed by this invention.

[0043] Combination Figure 1 , Figure 2 As shown, the diffuser consists of an inner ring 100, an outer ring 101, and a hollow support plate 102. The height of the hollow support plate 102 is less than the height 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 multiple sub-channels.

[0044] Combination Figures 3 to 11 As shown, this embodiment provides a gas tightness test fixture for the annular channel of a combustion chamber diffuser, including 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 press 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 of the base plate 1, the upper part of the column 7 is configured as a screw section 7a, the screw section 7a extends from the center hole of the cover plate 4 and is screwed with a first nut 8; multiple studs 11 are installed on the base plate 1, the upper end of the studs 11 passes through the cover plate 4 and is screwed with a second nut 10; a nozzle 5 is installed on the cover plate 4, and when the diffuser is assembled in the gas tightness test fixture, the 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 1a and an outer ring 1b; the lower sealing ring 2 is bonded to the top surface of the outer ring 1b; the inner ring 1a and the outer ring 1b are connected by eight support plates 1c, and a first relief hole 1d is formed between two adjacent support plates 1c; a plurality of second relief holes 4b are evenly distributed in a ring 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; after the lower end of the stud 11 is screwed into the stud mounting hole 1e, it is spot welded, and the number of weld points is 3 to 5.

[0047] Combination Figure 3 , Figure 4 and Figure 9 As shown, a column mounting hole 1f is provided at the center of the inner ring 1a; the lower end of the column 7 is provided with a plug-in section 7b and a flange plate 7c; 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 1a, and the flange plate 7c is fastened to the inner ring 1a by a third screw 14.

[0048] Combination Figure 4 and Figure 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 in sliding fit 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 Figure 10 As shown, a first washer 9 is provided between the first nut 8 and the cover plate 4. The first washer 9 is mounted on the cover plate 4 by a first screw 15. A U-shaped notch is provided on the first washer 9, which can rotate around the first screw 15, so that the U-shaped notch on the first washer 9 is engaged with the screw section 7a. The diameter of the central 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, and the upper end of the stud 11 passes through the stud through hole 4a. A second washer 12 is provided between the second nut 10 and the cover plate 4. The second washer 12 is mounted on the cover plate 4 by a second screw 13. A U-shaped notch is provided on the second washer 12, which can rotate around the second screw 13, so that the U-shaped notch on the second washer 12 is engaged with the stud 11. The diameter of the stud through hole 4a is larger than the outer diameter of the second nut 10.

[0050] By employing the above structure, when it is necessary to remove the cover plate 4 from the airtightness test fixture, simply loosen the first nut 8 and the second nut 10, and rotate the first pad 9 and the second pad 12 to disengage the first pad 9 from the screw section 7a and the second pad 12 from the stud 11. Since the diameter of the central hole of the cover plate 4 is larger than the outer diameter of the first nut 8 and the diameter 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 to remove the cover plate 4 from the airtightness test fixture. Conversely, when it is necessary to lock the cover plate 4, rotate the first pad 9 and the second pad 12 so that the U-shaped notch on the first pad 9 engages with the screw section 7a and the U-shaped notch on the second pad 12 engages with the stud 11, and then tighten the first nut 8 and the second nut 10 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 screwed onto the cover plate 4. A sealing gasket 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. The longitudinal section of the outer circumference of the connecting pipe is sawtooth-shaped, and the lower outer diameter φC of the connecting pipe is larger than the upper outer diameter φD, 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 airtightness of the annular channel of the combustion chamber diffuser, using the above-mentioned airtightness test fixture, including the following steps:

[0053] S1. Machin the upper end face A and lower end face B of the diffuser. The runout of the upper and lower end faces of the diffuser is required to be 0.05. This is to ensure the flatness of the diffuser end faces and enhance the sealing performance between the diffuser and the upper and lower sealing rings.

[0054] S2. Use a crane to lift the airtightness test fixture and diffuser into the water tank for wetting and then lift them out. The purpose of wetting is to enhance the sealing performance by utilizing the surface tension of water between the diffuser and the upper and lower sealing rings.

[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 a cotton cloth dipped in water, 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 air bubbles adsorbed on the surface of the diffuser with a cotton cloth.

[0058] S6. Adjust the control valve of the airtightness tester, adjust the air supply pressure to the set value and maintain it for a period of time. Observe whether there are bubbles emerging from the diffuser surface. If no bubbles emerge, it is qualified; if bubbles emerge, it is unqualified. Mark the unqualified areas for subsequent analysis of the reasons for the unqualified.

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

[0060] After the test, a crane was used to remove the clamps and diffuser from the water tank. After loosening the first nut 8 and the second nut 10, the cover plate 4 was removed, the diffuser was taken out and dried.

[0061] The above description is merely a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the present invention's specification and drawings under the inventive concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A test fixture for the airtightness of the annular channel of a combustion chamber diffuser, characterized in that, It includes 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 press 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 configured as a screw section (7a). The screw section (7a) extends out from the center hole of the cover plate (4) and is screwed with a first nut (8). Multiple studs (11) are installed on the base plate (1). The upper end of the stud (11) passes through the cover plate (4) and is screwed with a second nut (10). An air nozzle (5) is installed on the cover plate (4). After the diffuser is assembled into the airtightness test fixture, the air nozzle (5) is connected to the annular channel of the diffuser. The base plate (1) includes an inner ring (1a) and an outer ring (1b); the lower sealing ring (2) is bonded to the top surface of the outer ring (1b); the inner ring (1a) and the outer ring (1b) are connected by eight support plates (1c), and a first relief hole (1d) is formed between two adjacent support plates (1c); a plurality of second relief holes (4b) are evenly distributed in a ring on the cover plate (4). A stud mounting hole (1e) is provided on the support plate (1c); after the lower end of the stud (11) is screwed into the stud mounting hole (1e), it is spot welded, and the number of welds is 3 to 5. A column mounting hole (1f) is provided at the center of the inner ring (1a); a plug section (7b) and a flange plate (7c) are provided at the lower end of the column (7); The plug 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 the third screw (14).

2. The airtightness test fixture for the annular channel of a combustion chamber diffuser as described in claim 1, characterized in that, The middle section of the column (7) is a sliding fit section (7d); the central hole of the cover plate (4) is in sliding fit with the outer cylindrical surface of the sliding fit section (7d).

3. The airtightness test fixture for the annular channel of a combustion chamber diffuser as described in claim 1, characterized in that, A first washer (9) is provided between the first nut (8) and the cover plate (4). The first washer (9) is mounted on the cover plate (4) by a first screw (15). A U-shaped notch is provided on the first washer (9). The first washer (9) can rotate around the first screw (15) so that the U-shaped notch on the first washer (9) is engaged on the screw section (7a). The diameter of the central hole of the cover plate (4) is larger than the outer diameter of the first nut (8).

4. The airtightness test fixture for the annular channel of a combustion chamber diffuser as described in claim 1, characterized in that, A stud through hole (4a) is provided on the cover plate (4), and the upper end of the stud (11) passes through the stud through hole (4a). A second washer (12) is provided between the second nut (10) and the cover plate (4). The second washer (12) is installed on the cover plate (4) by the second screw (13). A U-shaped notch is provided on the second washer (12). The second washer (12) can rotate around the second screw (13) so that the U-shaped notch on the second washer (12) is locked on the stud (11). The diameter of the stud through hole (4a) is larger than the outer diameter of the second nut (10).

5. The airtightness test fixture for the annular channel of a combustion chamber diffuser as described in claim 1, characterized in that, The lower end of the air nozzle (5) is provided with an external thread and screwed onto the cover plate (4). A sealing gasket (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. The longitudinal section of the outer peripheral surface of the connecting pipe is serrated, and the outer diameter of the lower end of the connecting pipe is larger than the outer diameter of the upper end.

6. A method for testing the airtightness of the annular channel of a combustion chamber diffuser, characterized in that, The airtightness test fixture according to any one of claims 1 to 5 includes the following steps: S1. Machin the upper and lower end faces of the diffuser. The runout of the upper and lower end faces of the diffuser should be 0.

05. S2. Use a crane to lift the airtightness test fixture and diffuser into the water tank for wetting, 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 a cotton cloth dipped in water, 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). S4. Connect 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 air bubbles adsorbed on the surface of the diffuser with a cotton cloth. S6. Adjust the control valve of the airtightness tester, adjust the air supply pressure to the set value and continue for a period of time, observe whether there are bubbles emerging on the surface of the diffuser. If no bubbles emerge, it is qualified; if bubbles emerge, it is unqualified.

7. The airtightness test method for the annular channel of a combustion chamber diffuser as described in claim 6, characterized in that, In step S6, the gas supply pressure setting value is MPa, duration not less than 5 minutes.

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