Aero-engine lubricating oil system and fuel oil system bearing cavity sealing detection method

Abstract

The invention belongs to the field of sealing detection, and particularly relates to an aero-engine lubricating oil system and fuel oil system bearing cavity sealing detection method, which comprises the following steps: in a pressure maintaining stage, performing leakage detection on a detected cavity through an ultrasonic leakage detector within pressure maintaining time, and determining a leakage position; after the pressure maintaining stage is finished, recording pressure change data, comparing the pressure change data with a pressure value at the end of the pressure stabilizing time, judging whether the change value is greater than an allowable value or not, and considering that the sealing performance of the measured cavity is good; and if the pressure change data is greater than the allowable value after the pressure maintaining is finished, determining a leakage point by using an ultrasonic leakage instrument. Qualified inspection criteria are quantified through a direct pressure method airtight detection technology, the reliability of sealing inspection is improved, the sealing inspection capability of a large bearing cavity of a lubricating oil system and a fuel oil system is achieved, acoustic emission and a direct pressure method are combined, the position of a leakage source is rapidly and accurately positioned, the accuracy of leakage position judgment is improved, and the reliability of sealing inspection is improved. And meanwhile, the sealing detection efficiency is improved by more than 90%.

Description

Technical Field

[0001] This application belongs to the field of sealing testing, and specifically relates to a method for testing the sealing of bearing cavities in the lubricating oil system and fuel system of an aero-engine. Background Technology

[0002] The fuel and lubricating oil systems of aircraft engines are two important systems, and their sealing performance is crucial. Local seal failure can cause significant leakage and endanger flight safety.

[0003] Existing sealing systems have the following disadvantages:

[0004] (1) Poor reliability of sealing inspection

[0005] Currently, the results of engine lubricating oil system seal inspections cannot be quantified, human observation has a large consistency error, the inspection results are greatly affected by the inspectors, and the testing efficiency is extremely low.

[0006] (2) Poor accuracy in determining the location of the leak

[0007] Minor leaks are difficult to locate accurately through human observation, making it easy to miss them.

[0008] (3) Inspection measures for the lack of sealing in the fuel system and large bearing cavities

[0009] Currently, there are no sealing inspection measures after the fuel system is assembled, and large bearing cavities, due to their high oil consumption, also lack sealing inspection measures after assembly, making it impossible to guarantee assembly quality.

[0010] Therefore, researching an efficient and reliable method for testing the seals of fuel and lubricating oil systems is of great significance to improving the delivery cycle and quality of aero-engines. Summary of the Invention

[0011] To address the aforementioned issues, this application provides a method for detecting the seals of bearing cavities in the lubricating oil system and fuel system of an aero-engine, thereby resolving the problem of low efficiency in the prior art for detecting the seals of the lubricating oil system and fuel system.

[0012] The technical solution of this application is: a method for detecting the seal of bearing cavity in the lubricating oil system and fuel system of an aero-engine, comprising:

[0013] During the pressurization phase, air is introduced into the cavity under test until the air pressure value of the cavity under test meets the preset target value.

[0014] During the pressure holding phase, an ultrasonic leak detector is used to detect leaks in the tested cavity within the pressure holding time to determine the location of the leak.

[0015] After the pressure holding phase ends, record the pressure change data and compare it with the pressure value at the end of the stabilization time. Determine whether the change value is greater than the allowable value. If so, the tested cavity is considered to have good sealing performance. If the pressure change data is greater than the allowable value after the pressure holding phase ends, use an ultrasonic leak detector to determine the leak point.

[0016] If a leakage is confirmed, the leak point should be repaired and the sealing should be checked again.

[0017] Preferably, a pressure stabilization stage is set between the pressure holding stage and the pressure supply stage. In the pressure stabilization stage, the main valve of the nitrogen pressurization equipment is closed, and the pressure change data is observed after 1 minute. If the pressure change difference meets the set value, the gas pressure in the measured cavity is considered to be stable.

[0018] Preferably, the leakage detection of the cavity under test using an ultrasonic leak detector specifically involves:

[0019] Turn on the ultrasonic leak detector and adjust the receiving frequency to between 20 and 40 Hz. Place the ultrasonic leak detector 1 meter away from the cavity being tested, keeping it parallel to the cavity, and observe the leak point markings on the screen. When a leak point marking appears, it is considered a leak point.

[0020] Preferably, the specific method for filling the tested cavity with air during the pressurization stage is as follows: confirm that the throttle valve is in the closed state, open the main valve of the nitrogen pressurization equipment, adjust the throttle valve, and set the air pressure of the tested cavity to the required value.

[0021] Preferably, after the pressure holding stage is completed, a preset exhaust speed is set, and exhaust is performed by connecting the measured cavity to the external atmosphere through a control valve. The exhaust speed is less than or equal to the preset exhaust speed.

[0022] Preferably, the pressure holding time is 15 minutes, the allowable value is 0.01 MPa, and the pressure stabilization time is 1 minute.

[0023] The method for detecting the bearing cavity seal of the lubricating oil system and fuel system of an aircraft engine disclosed in this application has the following advantages:

[0024] By using direct pressure air tightness testing technology to quantify the inspection qualification criteria, the reliability of seal inspection is improved. It also has the ability to inspect the seals of large bearing cavities in lubricating oil systems and fuel systems. By combining acoustic emission with direct pressure method, the location of the leak source can be quickly and accurately located, improving the accuracy of leak location judgment, while increasing the seal inspection efficiency by more than 90%.

[0025] By combining the ultrasonic mechanism generated by the turbulence of leaking gas with the acoustic emission detection method and the direct pressure method, the location of the leak source can be quickly and accurately located, solving the problem that it is difficult to obviously detect minor leaks in existing sealing inspection methods and improving the accuracy of leak location determination. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the overall process of this application. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions in the embodiments of this application will be described in more detail below with reference to the accompanying drawings. In the drawings, the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The described embodiments are only some, not all, of the embodiments of this application. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application. The embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0028] The first aspect of this application provides a method for detecting the seal of the bearing cavity in the lubricating oil system and fuel system of an aircraft engine, such as... Figure 1 As shown, it includes the following steps:

[0029] In step S100, during the pressurization stage, air is introduced into the cavity to be tested until the air pressure value of the cavity meets the preset target value.

[0030] The pressurization phase is the air filling and evacuation process in the airtightness testing of the engine's external fuel lines and oil chamber. During the pressurization process, when the actual pressure value of the tested cavity is lower than the target pressure value, the system connects a positive pressure source to pressurize the tested cavity, increasing the pressure inside the cavity. By adjusting the total amount of air in the tested cavity, the system controls the pressure inside the cavity, ultimately ensuring that the pressure value inside the tested cavity meets the preset target value.

[0031] The specific operating procedure is as follows: confirm that the throttle valve is in the closed state, open the main valve of the nitrogen pressurization equipment, adjust the throttle valve, and set the inflation pressure of the chamber to be tested to the required value, which is related to the working pressure of the chamber to be tested, and is generally not greater than 0.6 MPa.

[0032] Preferably, a pressure stabilization phase is set between the pressure holding phase and the pressure supply phase. This stabilization phase serves as a buffer and transition point during the airtightness testing of the engine's external fuel lines and engine casing lubricating oil chamber. Generally, at the instant the inflation stops, the gas pressure in the tested cavity experiences a rapid rise or fall. Therefore, to ensure the accuracy of the airtightness test, a pressure stabilization phase is needed during the testing process to provide the time required for the gas in the tested cavity to stabilize and complete heat exchange.

[0033] The pressure stabilization time is required to be 1 minute. During the stabilization phase, close the main valve of the nitrogen pressurization equipment and observe the pressure change data after 1 minute. If the pressure change difference meets the set value, the gas pressure in the tested cavity is considered stable. The set value is set based on experience to ensure that the pressure fluctuation in the tested cavity is small.

[0034] In step S200, during the pressure holding stage, the cavity under test is tested for leakage using an ultrasonic leak detector within the pressure holding time to determine the location of the leak.

[0035] The pressure holding phase is a testing step in the process of checking the airtightness of the engine's external fuel lines and oil chamber. The change in gas pressure within the tested cavity is directly proportional to its leakage rate. The pressure change within the tested cavity is observed during the pressure holding period. The pressure holding time must be no less than 15 minutes.

[0036] If the pressure change in the tested cavity before and after the pressure holding stage exceeds the allowable value, further investigation to determine the leak location is necessary. The leak location is determined using the principle of acoustic emission; an ultrasonic leak detector is used to determine the leak location by detecting the ultrasound generated by the gas ejected from the leak.

[0037] Preferably, the leakage detection of the cavity under test using an ultrasonic leak detector specifically involves:

[0038] Turn on the ultrasonic leak detector and adjust the receiving frequency to between 20 and 40 Hz. Place the ultrasonic leak detector 1 meter away from the cavity being tested, keeping it parallel to the cavity, and observe the leak point markings on the screen. When a leak point marking appears, it is considered a leak point.

[0039] Preferably, a field pressure stage is set after the pressure holding stage. The field pressure stage is the atmospheric venting process during the airtightness testing of the engine's external fuel lines and the oil chamber of the casing. A preset exhaust speed is set. After the airtightness test of the pressure holding stage is completed, the chamber under test is connected to the external atmosphere through a control valve to exhaust the air. The exhaust speed must be less than or equal to the preset exhaust speed; otherwise, it may lead to unknown accidents. This completes one airtightness testing cycle.

[0040] Step S300: After the pressure holding phase ends, record the pressure change data and compare it with the pressure value at the end of the stabilization time. Determine if the change value is greater than the allowable value. If so, the tested cavity is considered to have good sealing performance and no leakage. If the pressure change data is greater than the allowable value after the pressure holding phase ends, use an ultrasonic leak detector to determine the leak point. The allowable value is 0.01 MPa.

[0041] In step S400, if leakage is confirmed, the leakage point is repaired and the sealing check is performed again. Leakage can be repaired by welding or replacing parts.

[0042] Some of the terms are defined as follows:

[0043] Pressure stabilization time: During the sealing inspection process, the gas pressure in the tested cavity is adjusted to the required value by adjusting the throttle valve, and the time from the moment the inflation stops to the moment the pressure stops fluctuating.

[0044] Pressure holding time: During the sealing inspection, the specified measurement time is taken after the gas pressure in the tested cavity stops fluctuating. If there is no leakage in the tested cavity during this time period, the pressure inside the cavity remains unchanged; if there is leakage in the sealed cavity, the change in gas pressure inside the tested cavity is proportional to the amount of leakage.

[0045] Pressure value: During the sealing inspection, the gas pressure value of the tested cavity is displayed through the pressure gauge at the output end of the throttle valve.

[0046] Required value: During the seal inspection process, the initial pressure setting of the tested cavity is related to the working pressure of the tested cavity, and generally should not exceed 0.6 MPa.

[0047] The allowable value is used to characterize the sealing effect of the tested cavity. If the working medium in the tested cavity is fuel oil or lubricating oil, the allowable value is generally 0.01 MPa / 15 min.

[0048] The testing process involves the following steps, as shown in Table 1:

[0049] Table 1. Equipment involved in the testing process

[0050]

[0051] In summary, this application has the following advantages:

[0052] This paper proposes a process method for inspecting the sealing performance of aero-engine fuel and lubricating oil systems using direct pressure gas sealing. It quantifies the criteria for passing the test, avoids the influence of human factors on the test results, improves the reliability of aero-engine fuel and lubricating oil system sealing inspection, and has the capability to inspect the sealing performance of large bearing cavities in the lubricating oil system and the fuel system.

[0053] By combining the ultrasonic mechanism generated by the turbulence of leaking gas with the acoustic emission detection method and the direct pressure method, the location of the leak source can be quickly and accurately located. This solves the problem that it is difficult to obviously detect small leaks in existing sealing inspection methods, improves the accuracy of leak location determination, and increases the sealing detection efficiency by more than 90%.

[0054] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for detecting the seal of bearing cavities in the lubricating oil system and fuel system of an aero-engine, characterized in that, include: During the pressurization phase, air is introduced into the cavity under test until the air pressure value of the cavity under test meets the preset target value. During the pressure holding phase, an ultrasonic leak detector is used to detect leaks in the tested cavity within the pressure holding time to determine the location of the leak. After the pressure holding phase ends, record the pressure change data and compare it with the pressure value at the end of the stabilization time. Determine whether the change value is greater than the allowable value. If so, the tested cavity is considered to have good sealing performance. If the pressure change data is greater than the allowable value after the pressure holding phase ends, use an ultrasonic leak detector to determine the leak point. If a leakage is confirmed, the leak point should be repaired and the sealing should be checked again.

2. The method for detecting the seal of bearing cavity in the lubricating oil system and fuel system of an aero-engine as described in claim 1, characterized in that, A pressure stabilization stage is set between the pressure holding stage and the pressure supply stage. During the pressure stabilization stage, the main valve of the nitrogen pressurization equipment is closed, and the pressure change data is observed after 1 minute. If the pressure change difference meets the set value, the gas pressure in the measured cavity is considered to be stable.

3. The method for detecting the seal of bearing cavity in the lubricating oil system and fuel system of an aero-engine as described in claim 1, characterized in that, The specific steps for detecting leaks in the tested cavity using an ultrasonic leak detector are as follows: Turn on the ultrasonic leak detector and adjust the receiving frequency to between 20 and 40 Hz. Place the ultrasonic leak detector 1 meter away from the cavity being tested, keeping it parallel to the cavity, and observe the leak point markings on the screen. When a leak point marking appears, it is considered a leak point.

4. The method for detecting the seal of bearing cavity in the lubricating oil system and fuel system of an aero-engine as described in claim 1, characterized in that, The specific method for filling the tested cavity with air during the pressurization stage is as follows: confirm that the throttle valve is closed, open the main valve of the nitrogen pressurization equipment, adjust the throttle valve, and set the air pressure of the tested cavity to the required value.

5. The method for detecting the seal of bearing cavity in the lubricating oil system and fuel system of an aero-engine as described in claim 1, characterized in that, After the pressure holding stage is completed, a preset exhaust speed is set, and the measured cavity is connected to the outside atmosphere through the control valve to exhaust the gas. The exhaust speed is less than or equal to the preset exhaust speed.

6. The method for detecting the seal of bearing cavity in the lubricating oil system and fuel system of an aero-engine as described in claim 1, characterized in that, The pressure holding time is 15 minutes, the allowable value is 0.01 MPa, and the pressure stabilization time is 1 minute.

Images