Lubricating oil system and method for removing aero-engine metal filings

Abstract

The invention provides a lubricating oil system and method for removing aero-engine metal filings, in the lubricating oil system, the oil outlet end of an external lubricating oil tank, an oil supply pump, a lubricating oil operation unit, an oil scavenger pump and the oil return end of the external lubricating oil tank are sequentially communicated through pipelines, and the lubricating oil tank is communicated with a pipeline between the lubricating oil operation unit and the oil scavenger pump through a pipeline. According to the lubricating oil system for removing the aero-engine metal filings, the external lubricating oil tank is adopted for testing, the smudginess degree of the engine lubricating oil tank is effectively reduced, according to the method for removing the aero-engine metal filings, on the basis of the external lubricating oil tank, the normal working oil pressure of the aero-engine is increased to 1.2 Mpa or above, and the service life of the aero-engine is prolonged. And the engine stays for a set time in a state corresponding to the resonance rotating speed, so that the service life of the engine is guaranteed, vibration operation with different frequencies is carried out in combination with a common rotating speed interval of the engine, and metal filing is removed through a resonance phenomenon.

Description

Technical Field

[0001] The invention belongs to the technical field of aircraft engines, and in particular relates to a lubricating oil system and method for removing metal chips from aircraft engines. Background Art

[0002] The metal chips in the aircraft engine mainly come from the following sources: parts casing residue, foreign objects during assembly and use, normal metal wear, etc. Excess metal chips may cause abnormal wear of the engine, or enter the lubricating oil system and be detected by the magnetic chip detector and filtered by the lubricating oil filter, or sink to the bottom of the lubricating oil tank and contaminate the lubricating oil. In addition, some metal chips will not fall off in a short period of time during factory testing, but will fall off under the influence of multiple factors after installation and use. Regardless of the consequences caused by excess metal chips, they increase the probability of engine failure, the difficulty and cost of field maintenance. Therefore, it is necessary to remove excess metal chips in the engine before it leaves the factory.

[0003] In addition, since the engine oil tank is designed as an integrated whole with the rest of the engine casing, it is affected by other engine accessories, pipes, lines, and the structural limitations of the oil tank itself, which directly leads to the difficulty in cleaning the metal chips accumulated in the oil tank.

[0004] And currently there is no method or concept specifically for removing excess metal chips from aircraft engines. Summary of the invention

[0005] In view of the above problems, the present invention proposes a lubricating oil system for removing metal chips from aircraft engines, comprising: a lubricating oil tank, an oil supply pump, a lubricating oil operation unit, and an oil return pump. The lubricating oil system also includes: an external lubricating oil tank;

[0006] The oil outlet end of the external lubricating oil tank, the oil supply pump, the lubricating oil working unit, the oil return pump, and the oil return end of the external lubricating oil tank are connected in sequence through pipelines, and the lubricating oil tank is connected to the pipeline between the lubricating oil working unit and the oil return pump through the pipeline.

[0007] Furthermore, the volume of the external oil tank is 1.5-2.5 times the volume of the oil tank.

[0008] Furthermore, a defoamer is installed in the external lubricating oil tank.

[0009] Furthermore, the lubricating oil system further comprises a three-way valve, the lubricating oil tank is connected to the first port of the three-way valve through a first pipeline, the lubricating oil operation unit is connected to the second port of the three-way valve through a second pipeline, the third port of the three-way valve is connected to the oil return pump through a pipeline, and a chip detector and a lubricating oil filter are installed on the first pipeline and the second pipeline;

[0010] A lubricating oil filter is also installed on the pipeline between the oil supply pump and the lubricating oil operating unit.

[0011] The present invention also provides a method for removing metal chips from an aircraft engine lubricating oil system, comprising the following steps:

[0012] Obtaining the steady-state speed of the free turbine of the engine in the lubricating oil operating unit;

[0013] Start the engine in the lubricating oil working unit to conduct slow acceleration and deceleration test and fast acceleration and deceleration test, and then obtain the gas generator resonance speed of the engine in the lubricating oil working unit;

[0014] Obtaining the resonance frequency corresponding to the resonance speed of the gas generator of the engine, and determining the residence time according to the resonance frequency;

[0015] Adjust the injection pressure of the lubricating oil nozzle of the engine in the lubricating oil operation unit to above 1.2Mpa;

[0016] The engine, oil supply pump and oil return pump in the lubricating oil operation unit are started synchronously, the free turbine of the engine in the lubricating oil operation unit rotates at a steady speed, and the gas generator of the engine rotates at a resonant speed;

[0017] The lubricating oil flows through the external lubricating oil tank, the oil supply pump, the lubricating oil working unit, and the oil return pump through the pipeline in turn to form a pipeline circulation. The engine in the lubricating oil working unit stops after running for a certain period of time to complete the chip removal operation.

[0018] Furthermore, the steady-state speed of the free turbine of the engine includes a minimum steady-state speed, a rated steady-state speed, and a maximum steady-state speed.

[0019] Furthermore, the slow acceleration and deceleration test is as follows: the gas generator is accelerated from the lowest steady-state speed to the highest steady-state speed, and then decelerated from the highest steady-state speed to the lowest steady-state speed, with an acceleration less than or equal to 1% of the maximum speed of the gas generator;

[0020] The rapid acceleration and deceleration test is as follows: taking a time less than or equal to 0.5s as the speed change time, accelerating the gas generator from the lowest steady-state speed to the maximum steady-state speed within the speed change time, and decelerating the gas generator from the maximum steady-state speed to the lowest steady-state speed within the speed change time.

[0021] Furthermore, the determination condition for obtaining the resonant speed of the gas generator of the engine in the lubricating oil operation unit is:

[0022] When the vibration peak value of the gas generator rotor is greater than 1.5 times the average vibration value of the gas generator rotor in the previous 5 seconds, or when the vibration peak value of the gas generator rotor is greater than 0.7 times the allowable vibration limit value, the speed corresponding to the gas generator rotor is the resonant speed.

[0023] Furthermore, the calculation formula for obtaining the resonance frequency corresponding to the resonance speed of the gas generator of the engine is:

[0024]

[0025] HZ expresses the resonant frequency corresponding to the resonant speed; H represents the constant ratio; N represents the resonant speed of the engine gas generator rotor; and P represents the standby frequency number of the engine gas generator speed at the combustion chamber nozzle.

[0026] Furthermore, the residence time is calculated as:

[0027]

[0028] T represents the dwell time that the engine needs to run; V represents the high cycle fatigue life of the engine turbine blades; HZ represents the resonant frequency corresponding to the resonant speed.

[0029] Furthermore, when the gas generator of the engine rotates at a resonant speed, the steady-state fluctuation of the gas generator speed is ±0.1%.

[0030] Compared with the prior art, the embodiments of the present invention have at least the following advantages:

[0031] 1. The lubricating oil system for removing metal chips from aircraft engines proposed by the present invention provides a new lubricating oil pipeline through an external lubricating oil tank. Compared with the lubricating oil tank of the engine, the external lubricating oil tank is easier to clean when the test is carried out, which effectively reduces the degree of dirtiness of the engine lubricating oil tank, realizes the maintenance of the original lubricating oil system, facilitates the effective removal of excess metal chips in the aircraft engine body, reduces the probability of engine failure, reduces the difficulty and cost of field maintenance, meets the test requirements of high pressure and high flow, and reduces the loss of the lubricating oil tank;

[0032] 2. The method for removing metal chips from an aircraft engine proposed in the present invention increases the normal operating oil pressure of the aircraft engine to above 1.2 MPa on the basis of an external lubricating oil tank, thereby increasing the injection pressure of the lubricating oil nozzle, enhancing the ability to remove metal chips, and allowing the engine to stay in a state corresponding to the resonant speed for a set time. While ensuring the service life of the engine, the metal chips are shaken off through the resonance phenomenon. In combination with the commonly used engine speed range, vibration operations of different frequencies are performed, and the engine gas temperature is changed in a short time to achieve the thermal expansion and contraction effect of the metal. While ensuring the accuracy of the resonant speed data, excess metal chips in the aircraft engine body are further removed. The lubricating oil flows through the external lubricating oil tank, the oil supply pump, the lubricating oil operation unit, and the oil return pump in sequence through the pipeline to form a pipeline circulation. While effectively realizing the cleaning operation of the engine metal chips, the pollution of the original lubricating oil tank by metal chips is avoided.

[0033] Other features and advantages of the present invention will be described in the following description, and partly become obvious from the description, or be understood by implementing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures pointed out in the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0035] Figure 1 A schematic diagram of a lubricating oil system for removing metal chips from an aircraft engine according to an embodiment of the present invention is shown;

[0036] Figure 2 A schematic diagram of a chip removal process for removing metal chips from an aircraft engine in an embodiment of the present invention is shown.

[0037] In the figure, there are a lubricating oil tank 1, an oil supply pump 2, a lubricating oil operating unit 3, an oil return pump 4, and an external lubricating oil tank 5. DETAILED DESCRIPTION

[0038] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are 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.

[0039] The present invention provides a lubricating oil system and method for removing metal chips from an aircraft engine. Figure 1 A schematic diagram of a lubricating oil system for removing metal chips from an aircraft engine in an embodiment of the present invention is shown. Figure 1 In the invention, the lubricating oil system for removing metal chips from an aircraft engine comprises a lubricating oil tank 1, a fuel supply pump 2, a lubricating oil operation unit 3, and a return oil pump 4. The lubricating oil system also comprises: an external lubricating oil tank 5;

[0040] The oil outlet end of the external lubricating oil tank 5, the oil supply pump 2, the lubricating oil working unit 3, the oil return pump 4, and the oil return end of the external lubricating oil tank 5 are connected in sequence through pipelines, and the lubricating oil tank 1 is connected to the pipeline between the lubricating oil working unit 3 and the oil return pump 4 through a pipeline.

[0041] The present application provides a new lubricating oil pipeline through an external lubricating oil tank 5, reduces the loss of the lubricating oil tank 1, meets the test requirements of high pressure and high flow, and the external lubricating oil tank 5 has the function of convenient cleaning and connection. The placement height of the external lubricating oil tank 5 is consistent with the original lubricating oil tank 1. The lubricating oil drawn back by the return oil pump 4 flows into the top of the external lubricating oil tank 5, and the oil supply pump 2 draws the lubricating oil from the bottom of the external lubricating oil tank. Compared with the lubricating oil tank 1 of the engine, the external lubricating oil tank 5 is easier to clean when testing, which effectively reduces the degree of dirtiness of the engine lubricating oil tank 1, realizes the maintenance of the original lubricating oil system, facilitates the effective removal of excess metal chips in the aircraft engine body, reduces the probability of engine failure, and reduces the difficulty and cost of field maintenance.

[0042] In order to further improve the efficiency of the lubricating oil system of the present application in cleaning metal chips, the lubricating oil pressure and the lubricating oil circulation volume in the lubricating oil system can be directly increased, and the upper limit of the speed of the engine in the lubricating oil system during operation can be increased. In this case, the lubricating oil flow rate in the lubricating oil pipeline will increase and the amount of air mixed with the inner wall of the lubricating oil will also increase, thereby causing a large number of bubbles to be generated in the lubricating oil. For this reason, the volume of the external lubricating oil tank 5 is set to be 1.5-2.5 times the volume of the lubricating oil tank 1. By expanding the volume of the external lubricating oil tank 5, the requirements of high pressure and large lubricating oil circulation volume in the lubricating oil system of the present application can be met.

[0043] Specifically, a defoamer is installed in the external lubricating oil tank 5, and a plurality of tiny holes are provided on the surface of the defoamer. When the lubricating oil passes through the defoamer, the defoamer breaks the bubbles, causing the gas to rise under the action of buoyancy and the oil to sink under the action of gravity, thereby achieving the effect of eliminating bubbles and accelerating the separation of gas from the lubricating oil.

[0044] At the same time, the installation height of the external oil tank 1 of the present application needs to be lower than or equal to the height of the oil tank 1, and the oil outlet and return ends of the external oil tank 5 are respectively located at the bottom and top of the side walls of the external oil tank 5, forming a high-in and low-out shape for the oil, thereby avoiding the tendency of the oil in the external oil tank 5 to flow toward the oil tank 1 and improving the stability of the oil flow.

[0045] Specifically, the lubricating oil system further includes a three-way valve, the lubricating oil tank 1 is connected to the first port of the three-way valve through a first pipeline, the lubricating oil operation unit 3 is connected to the second port of the three-way valve through a second pipeline, and the third port of the three-way valve is connected to the return oil pump 4 through a pipeline. The first pipeline and the second pipeline are both equipped with a chip detector 6 and a lubricating oil filter 7 to realize metal chip detection and metal chip filtering of the lubricating oil in the lubricating oil return pipeline;

[0046] The pipeline between the oil supply pump 2 and the lubricating oil operation unit 3 is also equipped with a lubricating oil filter 7 to detect and filter metal chips from the lubricating oil in the lubricating oil supply pipeline.

[0047] It should be noted that the above-mentioned chip detector 6 is a process magnetic chip detector and the lubricating oil filter 7 is a process lubricating oil filter. By using the process magnetic chip detector and the process lubricating oil filter to replace the original engine parts, the general filtering accuracy of the original engine return oil filter is 20μm, while the filtering accuracy of the lubricating oil filter 7 of the present application is not higher than 10μm, which can effectively filter tiny metal chips and reduce the loss of the lubricating oil filter 7. Correspondingly, the use of the process magnetic chip detector also reduces the loss of the engine magnetic chip detector 6.

[0048] refer to Figure 2 The present invention also proposes a method for removing metal chips from an aircraft engine lubricating oil system, comprising the following steps:

[0049] Obtaining the steady-state speed of the free turbine of the engine in the lubricating oil operation unit 3;

[0050] Start the engine in the lubricating oil working unit 3, first start the engine gas generator rotor, adjust the speed of the gas generator from zero to slow speed and keep it stable, during the process of increasing the speed of the gas generator, the high-temperature gas blows the free turbine to rotate, start the free turbine of the engine in the lubricating oil system, so that the speed of the free turbine begins to increase and finally stabilizes, then carry out slow acceleration and deceleration tests and fast acceleration and deceleration tests, and then obtain the resonant speed of the gas generator of the engine;

[0051] Obtaining the resonance frequency corresponding to the resonance speed of the gas generator of the engine, and determining the residence time according to the resonance frequency;

[0052] Regulate the injection pressure of the lubricating oil nozzle of the engine in the lubricating oil operation unit 3 to above 1.2Mpa;

[0053] The engine, the oil supply pump 2, and the oil return pump 4 in the lubricating oil operation unit 3 are started synchronously, the free turbine of the engine in the lubricating oil operation unit 3 rotates at a steady speed, and the gas generator of the engine rotates at a resonant speed;

[0054] The lubricating oil flows through the external lubricating oil tank 5, the oil supply pump 2, the lubricating oil working unit 3, and the oil return pump 4 in turn through the pipeline to form a pipeline circulation. The engine in the lubricating oil working unit 3 stops after running for a certain period of time, completing the chip removal operation.

[0055] It should be noted that the normal working oil pressure of an aircraft engine is about 0.4Mpa, and the maximum allowable working oil pressure is generally 1.4Mpa. The present application directly adjusts the injection pressure value of the engine's oil nozzle to above 1.2Mpa, thereby increasing the oil pressure of the oil system, thereby increasing the oil circulation volume in the oil system. For example, the oil circulation volume is increased by 2-3 times, further improving the ability of the oil to carry metal chips.

[0056] By starting the engine's gas generator to run at a resonant speed, the metal chips are shaken off by the resonance phenomenon, the cleaning effect of the metal chips is improved, and the operation time is limited, thereby protecting the service life of the turbine blades in the engine.

[0057] Among them, there will be three different standard steady-state speeds in the operation of the free turbine of an aircraft engine, namely, the steady-state speed of the engine's free turbine includes the minimum steady-state speed, the rated steady-state speed, and the maximum steady-state speed; by selecting standard values ​​at both end points of the free turbine and an average value in the middle, the simulation of various engine speeds is fully realized to achieve a comprehensive verification effect and realize the cleaning of metal chips under normal engine conditions.

[0058] In this case, there are three cases for synchronously starting the free turbine and gas generator of the engine, namely:

[0059] The free turbine rotates at a minimum steady speed, and the gas generator rotates at a resonant speed;

[0060] The free turbine rotates at a rated steady speed, and the gas generator rotates at a resonant speed;

[0061] The free turbine rotates at a maximum steady-state speed, and the gas generator rotates at a resonant speed.

[0062] Correspondingly, the slow acceleration and deceleration test in this application is: the operating state of the gas generator is changed with an acceleration less than or equal to 1% of the maximum speed of the gas generator, the free turbine is driven to accelerate from the lowest steady-state speed to the highest steady-state speed, and then decelerate from the maximum steady-state speed to the lowest steady-state speed, and the repeated process is repeated at least 3 times;

[0063] The maximum speed of the gas generator can be directly obtained through the engine parameters. The speed of the gas generator is gradually changed by taking 1% of the maximum speed of the gas generator as the acceleration. A comprehensive vibration scan is performed in the slow acceleration and deceleration test to accurately detect the resonant speed of the gas generator rotor.

[0064] The rapid acceleration and deceleration test in this application is: taking a time of less than or equal to 0.5s as the speed change time, changing the operating state of the gas generator within the speed change time, driving the gas generator to accelerate from the lowest steady-state speed to the maximum steady-state speed within the speed change time, and then driving the gas generator to decelerate from the maximum steady-state speed to the lowest steady-state speed within the speed change time, and repeating this process for at least 3 cycles;

[0065] While further determining the resonant speed of the gas generator rotor, the engine is made to experience thermal expansion and contraction in a short period of time during rapid acceleration and deceleration tests, thereby increasing the probability of metal chips falling and increasing the intensity of metal chip cleaning operations under normal engine conditions.

[0066] It should be noted that the turboshaft engine includes two rotors, one of which is the gas generator rotor, and the speed of the gas generator rotor can be infinitely adjusted between the engine slow speed state and the maximum speed state; the other is the free turbine rotor, which has three common working speeds (i.e., three gears), namely: the lowest steady-state speed np 1 , rated speed np 2 , maximum steady-state speed np 3 ; Among them, the free turbine is rotated by the high-temperature combustion gas generated by the gas generator.

[0067] During the process of changing the speed of the gas generator, the high-temperature gas generated by the gas generator will blow the free turbine to rotate, driving the free turbine of the engine to perform a rotational motion with a delayed change in speed. At the same time, the free turbine can also adjust the speed according to its own needs; and during the rotation of the free turbine, the rotation of the free turbine will synchronously feedback and affect the vibration level of the gas generator rotor itself.

[0068] In the above-mentioned slow acceleration and deceleration test and fast acceleration and deceleration test, a vibration sensor installed on the engine for measuring the fundamental frequency of the gas generator rotor is used to measure the vibration level of the gas generator rotor in real time and continuously. Correspondingly, the judgment condition in the process of obtaining the resonant speed of the gas generator of the engine in the lubricating oil working unit 3 is:

[0069] When the vibration peak value of the gas generator rotor is greater than 1.5 times the average vibration value of the gas generator rotor in the previous 5 seconds, or when the vibration peak value of the gas generator rotor is greater than 0.7 times the allowable limit value of the gas generator rotor vibration, the speed corresponding to the gas generator rotor is the resonant speed.

[0070] Through comprehensive evaluation of the sudden change and absolute value of the rotor vibration level, the rotor speed corresponding to the sudden increase in vibration amplitude is obtained based on the above judgment conditions, and the speed is determined to be the resonant speed, which is convenient for chip removal operations in the later stage. Among them, the allowable vibration limit value is the maximum design vibration value of the gas generator rotor, and the allowable vibration limit values ​​of different specifications are different.

[0071] The calculation formula for obtaining the resonance frequency corresponding to the resonance speed of the gas generator of the engine is:

[0072]

[0073] HZ represents the resonant frequency corresponding to the resonant speed; H represents the constant ratio, which is 60; N represents the resonant speed of the engine gas generator rotor; and P represents the standby frequency number of the engine gas generator speed at the combustion chamber nozzle.

[0074] For example, when the gas generator speed resonates at 10 standby frequencies of the combustion chamber nozzle, when the gas generator speed is 47000 r / min, the resonant frequency is:

[0075]

[0076] Among them, on the basis of obtaining the resonant frequency corresponding to the resonant speed, the calculation formula of the residence time is:

[0077]

[0078] T represents the dwell time of the engine; V represents the high cycle fatigue life of the engine turbine blade; HZ represents the resonant frequency corresponding to the resonant speed; and the high cycle fatigue life of the turbine blade in a conventional engine is 10 7 Second-rate.

[0079] Under the premise of not damaging the engine, it can achieve maximum work under high-frequency vibration speed, so as to increase the probability of metal chips falling under long-term vibration and improve chip removal efficiency.

[0080] In order to ensure the accuracy of the above-mentioned gas generator's rotation operation while maintaining a resonant speed, taking into account the differences in specifications of different aircraft engines and the errors in actual operation, when the engine's gas generator maintains a resonant speed while rotating, the steady-state fluctuation of the gas generator speed is ±0.1%.

[0081] In combination with the above limitations, the method for removing metal chips from aircraft engines is described:

[0082] First, the steady-state speed of the free turbine of the engine in the lubricating oil operation unit 3 is obtained, including: the minimum steady-state speed np 1 , rated steady-state speed np 2 , maximum steady-state speed np 3 ;

[0083] Start the engine and conduct slow acceleration and deceleration tests and fast acceleration and deceleration tests;

[0084] In this process, when the vibration peak value of the gas generator rotor is greater than 1.5 times the average vibration value of the gas generator rotor in the previous 5 seconds, or when the vibration peak value of the gas generator rotor is greater than 0.7 times the allowable limit value of the gas generator rotor vibration, the speed corresponding to the gas generator rotor is the resonant speed. It should be noted that, during the test of conventional aircraft engines, one to five resonant speeds are conventionally obtained. This embodiment is described here with four resonant speeds, which are: ng 1 ,ng 2 ,ng 3 ,ng 4 ;

[0085] In this application, the control accuracy of the steady-state speed of the aircraft engine and the impact of the manufacturing differences of different engines on the speed are taken into consideration. The steady-state fluctuation of the gas generator speed is generally ±0.5%. In order to ensure that the engine stays near the resonant speed, the steady-state fluctuation of the gas generator speed in this application is ±0.1%.

[0086] The corresponding resonant frequencies at the resonant speed are: HZ 1 , HZ 2 , HZ 3 , HZ 4 ;

[0087] The calculation formula of the resonance frequency is:

[0088]

[0089] The calculation formula based on the residence time is:

[0090]

[0091] T represents the dwell time of the engine, V represents the high cycle fatigue life of the turbine blades in the engine, and HZ represents the resonant frequency corresponding to the resonant speed. In this embodiment, the high cycle fatigue life of the turbine blades is 10 7 Second-rate;

[0092] The obtained residence time is: T 1 , T 2 , T 3 , T 4 ;

[0093] In the synchronous lubricating oil operation unit 3, the engine, the oil supply pump 2 and the oil return pump 4 are started, and the following operations are performed in sequence:

[0094] The injection pressure of the lubricating oil nozzle of the engine in the lubricating oil operation unit 3 is regulated to be 1.2Mpa;

[0095] Start the engine free turbine to maintain the minimum steady-state speed ng1 Rotate, the engine gas generator keeps ng 1 Rotate at a speed to maintain T 1 Duration; then adjust the engine gas generator to maintain ng 1 -1% of the speed to rotate, maintaining T 1 Duration; then adjust the engine gas generator to maintain ng 1 +1% speed to rotate, maintain T 1 Duration;

[0096] Start the engine free turbine to maintain the minimum steady-state speed np 2 Rotate, the engine gas generator keeps ng 2 Rotate at a speed of T 2 Duration; then adjust the engine gas generator to maintain ng 2 -1% of the speed to rotate, maintaining T 2 Duration; then adjust the engine gas generator to maintain ng 2 +1% speed to rotate, maintain T 2 Duration;

[0097] Start the engine free turbine to maintain the minimum steady-state speed np 3 Rotate, the engine gas generator keeps ng 3 Rotate at a speed to maintain T 3 Duration; then adjust the engine gas generator to maintain ng 3 -1% of the speed to rotate, maintaining T 3 Duration; then adjust the engine gas generator to maintain ng 3 +1% speed to rotate, maintain T 3 Duration;

[0098] The operation of the engine, the oil supply pump 2 and the oil return pump 4 is stopped to complete the chip removal operation.

[0099] The present invention proposes a method for removing metal chips from an aircraft engine based on the above-mentioned lubricating oil system for removing metal chips from an aircraft engine, which increases the normal working oil pressure of the aircraft engine to above 1.2 Mpa, thereby increasing the injection pressure of the lubricating oil nozzle, enhancing the ability to remove metal chips, and allowing the engine to stay in a state corresponding to the resonant speed for a set time, thereby ensuring the service life of the engine and shaking off the metal chips;

[0100] In addition, by combining the commonly used engine speed range, performing vibration operations of different frequencies, and changing the engine gas temperature in a short period of time to realize the thermal expansion and contraction effect of the metal, while ensuring the accuracy of the resonant speed data, further remove excess metal chips in the aircraft engine body, effectively realize the cleaning operation of the engine metal chips, and reduce the chance of engine failure.

[0101] Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent substitutions for some of the technical features therein; and these modifications or substitutions do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A lubricating oil system for removing metal chips from an aircraft engine, comprising: A lubricating oil tank (1), an oil supply pump (2), a lubricating oil operation unit (3), and an oil return pump (4), wherein the lubricating oil system further comprises: an external lubricating oil tank (5); The oil outlet end of the external lubricating oil tank (5), the oil supply pump (2), the lubricating oil operation unit (3), the oil return pump (4), and the oil return end of the external lubricating oil tank (5) are connected in sequence through pipelines, and the lubricating oil tank (1) is connected to the pipeline between the lubricating oil operation unit (3) and the oil return pump (4) through the pipeline.

2. The lubricating oil system for removing metal chips from aircraft engines according to claim 1, characterized in that: The volume of the external lubricating oil tank (5) is 1.5-2.5 times the volume of the lubricating oil tank (1).

3. The lubricating oil system for removing metal chips from aircraft engines according to claim 2, characterized in that: A defoamer is installed in the external lubricating oil tank (5).

4. The lubricating oil system for removing metal chips from aircraft engines according to claim 1, characterized in that: The lubricating oil system also includes a three-way valve, the lubricating oil tank (1) is connected to a first port of the three-way valve through a first pipeline, the lubricating oil operation unit (3) is connected to a second port of the three-way valve through a second pipeline, and the third port of the three-way valve is connected to an oil return pump (4) through a pipeline, and a chip detector (6) and a lubricating oil filter (7) are installed on the first pipeline and the second pipeline; A lubricating oil filter (7) is also installed on the pipeline between the oil supply pump (2) and the lubricating oil operation unit (3).

5. A method for removing metal chips from an aircraft engine based on the lubricating oil system for removing metal chips from an aircraft engine according to any one of claims 1 to 4, characterized in that: The steps include: Obtaining the steady-state speed of the free turbine of the engine in the lubricating oil operating unit (3); Starting the engine in the lubricating oil working unit (3) to perform a slow acceleration and deceleration test and a fast acceleration and deceleration test, thereby obtaining the gas generator resonance speed of the engine in the lubricating oil working unit (3); Obtaining the resonance frequency corresponding to the resonance speed of the gas generator of the engine, and determining the residence time according to the resonance frequency; Regulating the injection pressure of the lubricating oil nozzle of the engine in the lubricating oil operation unit (3) to a value above 1.2 MPa; Synchronously start the engine and the oil supply pump (2) in the lubricating oil operation unit (3) 、 The oil return pump (4) rotates the free turbine of the engine in the lubricating oil working unit (3) at a steady speed, and the gas generator of the engine rotates at a resonant speed; The lubricating oil flows through the external lubricating oil tank (5), the oil supply pump (2), the lubricating oil operation unit (3), and the oil return pump (4) in sequence through the pipeline to form a pipeline circulation. The engine in the lubricating oil operation unit (3) stops running after a dwell time, completing the chip removal operation.

6. The method for removing metal chips from an aircraft engine according to claim 5, characterized in that: The steady-state speed of the free turbine of the engine includes a minimum steady-state speed, a rated steady-state speed, and a maximum steady-state speed.

7. The method for removing metal chips from an aircraft engine according to claim 6, characterized in that: The slow acceleration and deceleration test is as follows: using an acceleration less than or equal to 1% of the maximum speed of the gas generator as the acceleration, accelerating the gas generator from the lowest steady-state speed to the highest steady-state speed, and then decelerating from the maximum steady-state speed to the lowest steady-state speed; The rapid acceleration and deceleration test is as follows: taking a time less than or equal to 0.5 s as the speed change time, accelerating the gas generator from the lowest steady-state speed to the maximum steady-state speed within the speed change time, and decelerating the gas generator from the maximum steady-state speed to the lowest steady-state speed within the speed change time.

8. The method for removing metal chips from an aircraft engine according to claim 7, characterized in that: The determination condition for obtaining the resonant speed of the gas generator of the engine in the lubricating oil operation unit (3) is: When the vibration peak value of the gas generator rotor is greater than 1.5 times the average vibration value of the gas generator rotor in the previous 5 seconds, or when the vibration peak value of the gas generator rotor is greater than 0.7 times the allowable vibration limit value, the speed corresponding to the gas generator rotor is the resonant speed.

9. The method for removing metal chips from an aircraft engine according to claim 8, characterized in that: The calculation formula for obtaining the resonance frequency corresponding to the resonance speed of the gas generator of the engine is: HZ expresses the resonant frequency corresponding to the resonant speed; H represents the constant ratio; N represents the resonant speed of the engine gas generator rotor; and P represents the standby frequency number of the engine gas generator speed at the combustion chamber nozzle.

10. The method for removing metal chips from an aircraft engine according to claim 9, characterized in that: The calculation formula of the residence time is: T represents the dwell time that the engine needs to run; V represents the high cycle fatigue life of the engine turbine blades; HZ represents the resonant frequency corresponding to the resonant speed.

11. The method for removing metal chips from an aircraft engine according to claim 1, characterized in that: When the gas generator of the engine rotates at a resonant speed, the steady-state fluctuation of the gas generator speed is ±0.1%.

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