A pressure test method for a combustion chamber with inner and outer casing structures

Abstract

The present invention discloses a pressure testing method for a combustion chamber with an inner and outer casing structure. The pressure testing method uses anti-wear hydraulic oil as a medium for transmitting pressure. By adjusting the oil pressure, the strength of the outer casing of the combustion chamber is tested at 2.0 times the maximum working pressure to prevent the casing from rupturing or bursting, resulting in gas leakage and affecting flight safety; the stability of the combustion chamber casing is tested at 1.5 times the maximum working pressure to prevent the casing from becoming unstable and deforming. The testing method can effectively conduct pressure testing research on the combustion chamber casing, and the casing tested by this method has been implemented and applied on this type of turboprop engine, and the performance is good.

Description

Technical Field

[0001] The present invention relates to the technical field of aircraft engine combustion chamber casing testing, and more particularly to a pressure testing method for a combustion chamber with an inner and outer casing structure. Background Art

[0002] Currently, testers conduct casing pressure tests to verify whether the engine casing has sufficient strength reserves, and understand the strength and failure modes of the engine casing and major load-bearing parts by measuring the strain and deformation of specified parts.

[0003] The combustion chamber of a certain engine model consists of a combustion chamber casing and a rear outer casing. The rear outer casing is the rear section of the combustion chamber casing. The combustion chamber casing is an integral welded part. The inner and outer casings are welded together by 10 support plates. It is the main load-bearing casing of the engine. Figure 1 As shown, the combustion chamber structure is unique, consisting of an inner and outer casing. The outer casing primarily comprises the front and rear casings, serving as the primary load-bearing components of the casing. The inner casing primarily comprises components such as ball bearing seats, roller bearing seats, and tapered beams. To reduce weight, the inner casing utilizes extensively 1.5mm-thick sheet metal, significantly thinner than the outer casing, which has a minimum wall thickness of 2.5mm. A stress analysis of the engine combustion chamber reveals that the combustion chamber primarily withstands flight maneuvering loads, its own pressure, and temperature loads. The outer casing experiences significant loads, including circumferential internal aerodynamic forces, thermal stresses, and axial forces and torques from the front and rear mounting edges. Compared to the outer casing, the inner casing does not experience forces transmitted from the turbine and compressor casings through the front and rear mounting edges, resulting in relatively lower loads. Therefore, testing the combustion chamber of this turboprop engine at twice the conventional maximum operating pressure is considered excessively harsh for the inner casing.

[0004] Invention application CN110926921A discloses a pressure test system for the outer casing of a combustion chamber. The application performs a pressure load test on the outer casing of the combustion chamber, but does not test the pressure load of the inner casing of the combustion chamber. In addition, no pressure test has been conducted on a casing with a special structure of inner and outer casings in China so far. Therefore, a pressure test method for a combustion chamber with an inner and outer casing structure is urgently needed. Summary of the Invention

[0005] In order to solve the above technical problems, the present invention provides a pressure testing method for a combustion chamber with an inner and outer casing structure.

[0006] The purpose of the present invention is achieved through the following technical solutions:

[0007] A pressure test method for a combustion chamber having an inner and outer casing structure comprises the following steps:

[0008] Inner casing pressure test:

[0009] S1. Install the test adapter section 1 and the test adapter section 2 on the combustion chamber;

[0010] S2, injecting hydraulic oil into the combustion chamber through the oil injection hole to apply pressure load;

[0011] S3. Preload: Load the load step by step at 5-10% increments to 40-50% of the test load at 1.5 times the maximum working pressure, and then unload the load step by step after loading.

[0012] S4, Simulated load: Load step by step every 5-10% to 100% of the test load;

[0013] Outer casing pressure test:

[0014] S1. Install the second test adapter section on the combustion chamber and seal the oil return pipe;

[0015] S2, injecting hydraulic oil into the combustion chamber through the oil injection hole to apply pressure load;

[0016] S3. Preload: Load the load step by step by 5-10% at 2 times the maximum working pressure until it reaches 40-50% of the test load. Unload the load step by step after completion.

[0017] S4. Simulated load: Load step by step every 5-10% to 100% of the test load.

[0018] Furthermore, the combustion chamber includes an inner casing and an outer casing; the inner casing forms the inner wall of the combustion chamber, and the inner wall of the combustion chamber is a tubular structure with openings at both ends, and is sealed and connected by a test transition section 1 to form an inner cavity of the combustion chamber; the inner cavity of the combustion chamber is provided with an oil return pipe connected to the external environment; the outer casing forms the outer wall of the combustion chamber, and the outer wall of the combustion chamber is a tubular structure with openings at both ends, and is sealed and connected by a test transition section 2 at both ends to form an outer cavity of the combustion chamber; the test transition section 2 is provided with an oil filling hole.

[0019] Furthermore, the test transition section 1 is fixedly connected to the combustion chamber by bolts.

[0020] Furthermore, the second test transition section is fixedly connected to the combustion chamber by bolts.

[0021] Furthermore, the test transition section 2 is provided with a pressure sensor.

[0022] Furthermore, strain data collectors are provided on the inner casing and the outer casing.

[0023] Furthermore, in the inner casing pressure test S4, the load holding time at each level is ≥3s, and the holding time at the maximum load state is ≥5min.

[0024] Furthermore, in the outer casing pressure test step S4, the load holding time at each level is ≥3s, and the holding time at the maximum load state is ≥5min.

[0025] Furthermore, the inner casing and outer casing pressure test further includes unloading the pressure value to zero after the S4 simulated load is completed.

[0026] Furthermore, the inner and outer casings further include an inspection step after the S4 simulated load, and the inspection step includes inspecting the casing appearance and measuring the casing dimensions.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] The present invention proposes a new pressure test method for the structural and stress analysis of the inner and outer casings of the combustion chamber. This method conducts a strength assessment on the outer casing of the combustion chamber at 2.0 times the maximum working pressure to prevent the casing from rupturing or bursting, thereby causing gas leakage and affecting flight safety; the stability of the combustion chamber casing is assessed at 1.5 times the maximum working pressure to prevent the casing from becoming unstable and deforming. This test method can effectively conduct pressure testing research on the combustion chamber casing, and the casings that have passed the assessment by this method have been implemented and applied on this type of turboprop engine and are in good use. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a structural schematic diagram of a combustion chamber with an inner and outer casing structure;

[0030] Figure 2 This is a schematic diagram of the structure of the test transition section 1 and the test transition section 2 installed on the combustion chamber;

[0031] Figure 3 This is a flow chart of the inner casing pressure test method of the present invention;

[0032] Figure 4 This is a flow chart of the outer casing pressure test method of the present invention;

[0033] Among them: 1. Outer casing; 2. Inner casing; 3. Oil return pipe; 4. Test adapter section 1; 5. Test adapter section 2; 6. Pressure sensor; 7. Oil filling hole. DETAILED DESCRIPTION

[0034] To clearly illustrate the technical features of this solution, the present invention is described in detail below through specific implementation methods and in conjunction with the accompanying drawings. Many specific details are described in the following description to facilitate a full understanding of the present application. However, the present application can also be implemented in other ways different from those described herein. Therefore, the scope of protection of the present application is not limited by the specific embodiments disclosed below. In addition, in the description of the present application, it should be understood that the terms "center", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "axial", "radial", "circumferential", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings. They 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 operate in a specific orientation. Therefore, they should not be understood as limiting the present application. In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly indicate the number of technical features indicated. Therefore, features defined as "first" or "second" can explicitly or implicitly include one or more of such features. In the description of this application, "plurality" means two or more, unless otherwise specified or specifically defined. In this application, unless otherwise specified or defined, terms such as "mounted," "connected," "connected," and "fixed" should be interpreted broadly. For example, they can refer to fixed, removable, or integrated connections; mechanical, electrical, or communication connections; direct or indirect connections through an intermediary; internal communication between two components; or interaction between two components. A person skilled in the art will understand the specific meanings of these terms in this application based on the specific circumstances. In this application, unless otherwise specified or defined, a first feature being "above" or "below" a second feature can mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediary. In this specification, references to the terms "one embodiment," "some embodiments," "examples," "specific examples," or "some examples" mean that the specific features, structures, materials, or characteristics described in connection with that embodiment or example are included in at least one embodiment or example of this application. In this specification, schematic representations of these terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0035] Example 1

[0036] An embodiment provided by the present invention is a method for pressure testing a combustion chamber having an inner and outer casing structure.

[0037] According to the load and strength analysis of the casing bearing parts, the casing inside the combustion chamber meets the "medium-length" shell condition, which can be expressed as:

[0038]

[0039] From this, the critical pressure q when the inner casing is unstable and deformed can be calculated KP , the expression is:

[0040]

[0041] Then, the critical pressure of the combustion chamber casing instability and the maximum working pressure q 工作max The instability assessment pressure coefficient K is calculated to be 1.5 times, and the expression is:

[0042]

[0043] Among them, E is the elastic modulus, h is the thickness of the shell, R is the radius of the shell, L is the length of the shell, and υ is Poisson's ratio.

[0044] Therefore, the inner casing of the combustion chamber is tested for stability at 1.5 times the maximum working pressure, and the outer casing is tested at twice the maximum working pressure. A pressure test method for a combustion chamber with an inner and outer casing structure includes the following steps:

[0045] Inner casing pressure test:

[0046] S1. Install the test transition section 1 4 and the test transition section 2 5 on the combustion chamber;

[0047] S2, injecting hydraulic oil into the combustion chamber through the oil injection hole 7 to apply pressure load;

[0048] S3, Preload: According to 1.5 times the maximum working pressure, load step by step every 5% to 40% of the test load, and then unload step by step after loading. Each load level is maintained for 3 seconds, and the maximum load state is maintained for 5 minutes;

[0049] S4, Simulated load: Load step by step every 5% to 100% of the test load;

[0050] Outer casing pressure test:

[0051] S1. Install the second test adapter section 5 on the combustion chamber and seal the oil return pipe 3;

[0052] S2, injecting hydraulic oil into the combustion chamber through the oil injection hole to apply pressure load;

[0053] S3, Preload: According to 2 times the maximum working pressure, load every 5 steps to 40% of the test load, and then unload step by step after loading. Each load level is maintained for 3 seconds, and the maximum load state is maintained for 5 minutes;

[0054] S4. Simulated load: Load step by step every 5% to 100% of the test load.

[0055] The combustion chamber includes an inner casing 2 and an outer casing 1; the inner casing 2 forms the inner wall of the combustion chamber, and the inner wall of the combustion chamber is a tubular structure with open ends, and is sealed and connected by a test transition section 1 4 to form the inner cavity of the combustion chamber; the inner cavity of the combustion chamber is provided with an oil return pipe 3 to communicate with the external environment; the outer casing 1 forms the outer wall of the combustion chamber, and the outer wall of the combustion chamber is a tubular structure with open ends, and is sealed and connected by a test transition section 2 5 at both ends to form the outer cavity of the combustion chamber; the test transition section 2 is provided with an oil filling hole 7.

[0056] The test transition section 1-4 is fixedly connected to the combustion chamber by bolts.

[0057] The test transition section 2 5 is fixedly connected to the combustion chamber by bolts.

[0058] After the S4 simulated load is completed, the pressure value is unloaded to zero, and the inner and outer casings are inspected. The inspection items include inspecting the appearance of the casing and measuring the dimensions of the casing.

[0059] Example 2

[0060] This embodiment provides a pressure test method for a combustion chamber having an inner and outer casing structure, wherein the test is performed by changing the test loading pressure parameters, including the following steps:

[0061] Inner casing pressure test:

[0062] S1. Install the test transition section 1 4 and the test transition section 2 5 on the combustion chamber;

[0063] S2, injecting hydraulic oil into the combustion chamber through the oil injection hole 7 to apply pressure load;

[0064] S3. Preload: According to 1.5 times the maximum working pressure, load step by step every 10% to 50% of the test load. After loading, unload step by step. Each load level is maintained for 10 seconds, and the maximum load state is maintained for 10 minutes;

[0065] S4, Simulated load: Load step by step every 10% to 100% of the test load;

[0066] Outer casing pressure test:

[0067] S1. Install the second test adapter section 5 on the combustion chamber and seal the oil return pipe 3;

[0068] S2, injecting hydraulic oil into the combustion chamber through the oil injection hole 7 to apply pressure load;

[0069] S3. Preload: Load at 2 times the maximum working pressure, step by step, 10% at a time, to 50% of the test load. After loading, unload step by step. Each load level is maintained for 10 seconds, and the maximum load state is maintained for 10 minutes.

[0070] S4. Simulated load: Load step by step every 10% to 100% of the test load.

[0071] The combustion chamber includes an inner casing 2 and an outer casing 1; the inner casing 2 forms the inner wall of the combustion chamber, and the inner wall of the combustion chamber is a tubular structure with open ends, and is sealed and connected by a test transition section 4 to form the inner cavity of the combustion chamber; the inner cavity of the combustion chamber is provided with an oil return pipe 3 to communicate with the external environment; the outer casing 1 forms the outer wall of the combustion chamber, and the outer wall of the combustion chamber is a tubular structure with open ends, and is sealed and connected with a test transition section 2 5 at both ends to form the outer cavity of the combustion chamber; the test transition section 2 5 is provided with an oil filling hole 7.

[0072] The test transition section 1-4 is fixedly connected to the combustion chamber by bolts.

[0073] The test transition section 2 5 is fixedly connected to the combustion chamber by bolts.

[0074] After the S4 simulated load is completed, the pressure value is unloaded to zero, and the inner and outer casings are inspected. The inspection items include inspecting the appearance of the casing and measuring the dimensions of the casing.

[0075] Example 3

[0076] This embodiment provides a pressure test method for a combustion chamber having an inner and outer casing structure. Unlike the second embodiment, this embodiment adds a strain data collector and a pressure sensor to monitor the test process, including the following steps:

[0077] Inner casing pressure test:

[0078] S1. Install the test transition section 1 4 and the test transition section 2 5 on the combustion chamber;

[0079] S2, injecting hydraulic oil into the combustion chamber through the oil injection hole 7 to apply pressure load;

[0080] S3. Preload: According to 1.5 times the maximum working pressure, load step by step every 10% to 50% of the test load. After loading, unload step by step. Each load level is maintained for 10 seconds, and the maximum load state is maintained for 10 minutes;

[0081] S4, Simulated load: Load step by step every 10% to 100% of the test load;

[0082] Outer casing pressure test:

[0083] S1. Install the second test adapter section 5 on the combustion chamber and seal the oil return pipe 3;

[0084] S2, injecting hydraulic oil into the combustion chamber through the oil injection hole 7 to apply pressure load;

[0085] S3. Preload: Load at 2 times the maximum working pressure, step by step, 10% at a time, to 50% of the test load. After loading, unload step by step. Each load level is maintained for 10 seconds, and the maximum load state is maintained for 10 minutes.

[0086] S4. Simulated load: Load step by step every 10% to 100% of the test load.

[0087] The combustion chamber includes an inner casing 2 and an outer casing 1; the inner casing 2 forms the inner wall of the combustion chamber, and the inner wall of the combustion chamber is a tubular structure with open ends, and is sealed and connected by a test transition section 4 to form the inner cavity of the combustion chamber; the inner cavity of the combustion chamber is provided with an oil return pipe 3 to communicate with the external environment; the outer casing 1 forms the outer wall of the combustion chamber, and the outer wall of the combustion chamber is a tubular structure with open ends, and is sealed and connected with a test transition section 2 5 at both ends to form the outer cavity of the combustion chamber; the test transition section 2 5 is provided with an oil filling hole 7.

[0088] The test transition section 1 5 is fixedly connected to the combustion chamber by bolts.

[0089] The test transition section 2 5 is fixedly connected to the combustion chamber by bolts.

[0090] After the S4 simulated load is completed, the pressure value is unloaded to zero, and the inner and outer casings are inspected. The inspection items include inspecting the appearance of the casing and measuring the dimensions of the casing.

[0091] Furthermore, the test adapter section 2 6 is provided with a pressure sensor, and the inner casing 2 and the outer casing 1 are provided with a strain data collector, which can collect and record the pressure data and strain data during the test, facilitate the monitoring of the pressure and casing load conditions during the test, and facilitate subsequent test analysis.

[0092] Obviously, the above embodiments of the present invention are merely examples for the purpose of clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. Those skilled in the art will appreciate that other variations or modifications can be made based on the above description. It is not necessary and impossible to enumerate all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the claims of the present invention.

Claims

1. A pressure test method for a combustion chamber with an inner and outer casing structure, characterized in that: The following steps are involved: Inner casing pressure test: S1. Install the test transition section 1 and the test transition section 2 on the combustion chamber, wherein the combustion chamber includes an inner casing and an outer casing; the inner casing forms the inner wall of the combustion chamber, which is a tubular structure with open ends and is sealed and connected by the test transition section 1 to form the combustion chamber cavity; the combustion chamber cavity is provided with an oil return pipe connected to the external environment; the outer casing forms the outer wall of the combustion chamber, which is a tubular structure with open ends and is sealed and connected by the test transition section 2 at both ends to form the combustion chamber cavity; the test transition section 2 is provided with an oil filling hole; S2, injecting hydraulic oil into the combustion chamber through the oil injection hole to apply pressure load; S3. Preload: According to 1.5 times the maximum working pressure, load step by step every 5~10% to 40~50% of the test load, and unload step by step after loading; S4, Simulated load: Load step by step every 5~10% to 100% of the test load; Outer casing pressure test: S1. Install the second test adapter section on the combustion chamber and seal the oil return pipe; S2, injecting hydraulic oil into the combustion chamber through the oil injection hole to apply pressure load; S3. Preload: Load the load step by step by 5-10% at 2 times the maximum working pressure until it reaches 40-50% of the test load. Unload the load step by step after completion. S4. Simulated load: Load step by step every 5~10% to 100% of the test load.

2. A pressure test method for a combustion chamber with an inner and outer casing structure according to claim 1, characterized in that: The test transition section 1 is fixedly connected to the combustion chamber via bolts.

3. A pressure test method for a combustion chamber with an inner and outer casing structure according to claim 1, characterized in that: The second test transition section is fixedly connected to the combustion chamber by bolts.

4. A pressure test method for a combustion chamber with an inner and outer casing structure according to claim 1, characterized in that: The second test transition section is provided with a pressure sensor.

5. The pressure test method for a combustion chamber with an inner and outer casing structure according to claim 1, characterized in that: The inner casing and the outer casing are provided with strain data collectors.

6. A pressure test method for a combustion chamber with an inner and outer casing structure according to claim 1, characterized in that: In the inner casing pressure test S4, each load level is maintained for ≥3s, and the maintenance time under the maximum load state is ≥5min.

7. A pressure test method for a combustion chamber with an inner and outer casing structure according to claim 1, characterized in that: In the outer casing pressure test S4, each load level is maintained for ≥3s, and the maintenance time under the maximum load state is ≥5min.

8. The pressure test method for a combustion chamber with an inner and outer casing structure according to claim 1, characterized in that: The inner casing and outer casing pressure test also includes unloading the pressure value to zero after the S4 simulated load is completed.

9. A pressure test method for a combustion chamber with an inner and outer casing structure according to claim 1, characterized in that: The inner and outer casings further include an inspection step after the S4 simulated load, and the inspection step includes inspecting the casing appearance and measuring the casing dimensions.

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