A method for ruling out carbon deposit blockage fault of an aero-engine fuel manifold

Abstract

The application discloses a kind of methods for excluding aero-engine fuel manifold carbon deposition blockage fault, first using cleaning fluid flushing, then using tap water rinsing, again through pure water rinsing, finally again using compressed air to blow dry fuel manifold;Fuel manifold is washed positively after using cleaning fluid, and the fuel manifold is installed on the vibration backwashing test device, the vibration motor is started while starting backwashing equipment, and the main and auxiliary oil circuits of the fuel manifold are respectively vacuumed, after backwashing is finished, reverse flushing is carried out again;When vacuuming, the fuel manifold is vacuumed in reverse, when reverse flushing, the inlet pipe is connected to the nozzle of the fuel manifold, the outlet pipe is connected to the main and auxiliary oil circuits of the fuel manifold, and reverse flushing is carried out.The beneficial effects of the present application are: to prevent the product performance from being unqualified due to carbon deposition blockage of fuel manifold, to save the cost of replacing parts, to improve the stability of engine fuel combustion during the use period after repair, and to improve the safety of aero-engine use.

Description

Technical Field

[0001] This invention relates to carbon buildup in the fuel manifold, and more particularly to a method for troubleshooting carbon buildup in the fuel manifold of an aircraft engine. Background Technology

[0002] The aircraft engine's fuel manifold is located in the main combustion chamber and supplies fuel to 28 centrifugal fuel nozzles. There are two fuel manifolds: a main fuel manifold and a secondary fuel manifold. The fuel manifold is equipped with 28 centrifugal nozzles, such as... Figure 1 As shown, the fuel manifold is located within the main combustion chamber. To prevent damage from high temperatures, it has three layers of insulation on its outer surface: the first layer is fiberglass, the second is asbestos cloth, and the third is a metal partition. The fuel manifold determines the fuel supply to the entire main combustion chamber. A malfunction in the fuel manifold will cause uneven fuel supply, affecting the quality of fuel combustion and the temperature distribution within the main combustion chamber. This, in turn, will affect the engine's operational stability and quality, and may even jeopardize the aircraft's flight safety.

[0003] The fuel manifold operates in a high-temperature environment. After fuel supply stops, residual fuel remains inside. Under high temperatures, this fuel carbonizes, producing carbon deposits that accumulate on the inner wall of the manifold. During product use, carbon deposits on the inner wall will affect the engine's stability and safety. During product repair, carbon deposits inside the manifold can cause blockages, affecting product performance during testing. If the carbon deposits cannot be removed, the test performance will fail, necessitating the scrapping of the fuel manifold. The cost of a single fuel manifold for an aircraft engine is high; replacing it would significantly increase repair costs. Statistics show that the cost of replacing a fuel manifold due to unresolved carbon deposit issues exceeds 1 million yuan annually. Furthermore, the fuel manifold is a one-piece cast structure and cannot be disassembled for repair.

[0004] The existing method for removing carbon deposits from the fuel manifold only uses flushing equipment and ordinary kerosene as the flushing fluid. Relying solely on the impact force of the liquid flow to remove carbon deposits from the pipe wall is inefficient and ineffective in removing some stubborn carbon deposits. This results in some fuel manifold internal carbon buildup on the pipe walls, causing blockages and ultimately leading to performance failures during testing. In such cases, replacement with new fuel manifolds is necessary, but new fuel manifolds are expensive, with annual replacement costs exceeding 1 million RMB due to this problem. Furthermore, even when some fuel manifolds pass testing and are delivered, incompletely removed carbon deposits accumulate and thicken with engine use, affecting combustion stability and engine quality. Therefore, there is an urgent need to develop a method for efficiently and quickly removing carbon deposits from the inner walls of the fuel manifold, improving the safety and reliability of the product after repair, while simultaneously reducing replacement costs. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a method for eliminating carbon buildup and blockage in the fuel manifold of an aircraft engine.

[0006] The objective of this invention is achieved through the following technical solution: a method for eliminating carbon buildup and blockage in the fuel manifold of an aircraft engine, comprising the following steps: Cleaning fluid circulation flushing: During flushing, add cleaning fluid into the flushing equipment, then flush with cleaning fluid first, then rinse with tap water, then rinse with pure water, and finally dry the fuel main pipe with compressed air. Vacuum back-drafting and reverse flushing of fuel main: After the fuel main is flushed in the forward direction with cleaning fluid, the fuel main is installed on the vibration back-drafting and flushing tester. The vibration motor is turned on while the back-flushing equipment is started to evacuate the main and auxiliary oil circuits of the fuel main. After the back-drafting is completed, reverse flushing is performed at a pressure of 4.5 kgf / cm2~5.5 kgf / cm2 for 4min~6min. Vacuum back-drafting and back-flushing: During vacuum back-drafting, the back-drafting pipeline is connected to the main and auxiliary fuel lines of the fuel main pipe to perform reverse vacuuming of the fuel main pipe. During back-flushing, the fuel inlet pipeline is connected to the nozzle of the fuel main pipe, and the fuel outlet pipeline is connected to the main and auxiliary fuel lines of the fuel main pipe to perform reverse flushing.

[0007] Optionally, during rinsing, the rinsing time with cleaning solution shall not be less than 10 minutes, while the rinsing time with tap water shall be 18 to 22 minutes, and the rinsing time with pure water shall be 4 to 6 minutes.

[0008] Optionally, the rinsing time is 20 minutes with tap water or 5 minutes with pure water.

[0009] Optionally, the main and auxiliary fuel lines of the fuel main can be evacuated for 5 minutes, and the pressure during backflushing is 5 kgf / cm2, which is maintained for 5 minutes.

[0010] Optionally, the cleaning solution can be formulated as follows: sodium hydroxide: 0.5~1.5wt%; industrial sodium phosphate: 1.5-2.5wt%; sodium tripolyphosphate: 2.5-3.5wt%; the remainder is water.

[0011] Optionally, the cleaning solution can be formulated as follows: potassium hydroxide 0.5-1.5 wt%; industrial sodium phosphate 1.5-2.5 wt%; sodium tripolyphosphate 2.5-3.5 wt%; the remainder being water.

[0012] Optionally, the cleaning solution can be formulated as follows: sodium hydroxide: 1 wt%; industrial sodium phosphate: 2 wt%; sodium tripolyphosphate: 3 wt%; the remainder is water.

[0013] Optionally, the cleaning solution can be prepared as follows: potassium hydroxide: 1 wt%; industrial sodium phosphate: 2 wt%; sodium tripolyphosphate: 3 wt%; the remainder is water.

[0014] Optionally, the backflushing equipment includes a pressurized flushing section, a vibrating table, and a back-extraction section. A fuel main pipe is placed on the vibrating table. The back-extraction section is connected to the main fuel line and the auxiliary fuel line through pipelines. The main fuel line and the auxiliary fuel line are respectively connected to the nozzles of the fuel main pipe. The pressurized flushing section is connected to the nozzles of the main pipe through an oil inlet pipeline.

[0015] This invention offers the following advantages: The method for troubleshooting carbon buildup blockage in the fuel manifold uses a specialized cleaning fluid instead of kerosene. Besides relying on the liquid flow to impact the carbon deposits, it also dissolves the carbon deposits on the pipe wall through chemical action, without causing corrosion or other damage, thus improving flushing efficiency and quality. Furthermore, a vibration-assisted reverse flushing method is developed, where the fuel manifold, after forward flushing, is vibrated while simultaneously undergoing reverse vacuuming and reverse flushing to prevent larger carbon particles from becoming stuck inside the manifold. This method eliminates performance defects caused by carbon buildup blockage in the fuel manifold, saves on replacement costs, improves the fuel combustion stability of the engine during its post-repair service life, and ultimately enhances the safety of aircraft engines. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the fuel main pipe. Figure 2 A schematic diagram illustrating the vacuuming and backwashing principles of a backwashing device; Figure 3 This is a schematic diagram showing the connection between the nozzle and the oil passage; Figure 4 This is a schematic diagram of the quick connector. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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 some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0018] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0019] It should be noted that, unless otherwise specified, the embodiments and features described in this invention can be combined with each other.

[0020] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0021] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this invention is in use, or the orientation or positional relationship commonly understood by those skilled in the art. They are only used for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention. In addition, the terms "first," "second," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0022] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0023] like Figure 2 As shown, a method for troubleshooting carbon buildup blockage in an aircraft engine fuel manifold includes the following steps: Cleaning fluid circulation flushing: During flushing, cleaning fluid is added to the flushing equipment, followed by flushing with the cleaning fluid, then rinsing with tap water, then rinsing with pure water, and finally drying the fuel main pipe with compressed air. In this embodiment, the flushing time with the cleaning fluid is no less than 10 minutes, while the rinsing time with tap water is 18-22 minutes, and the rinsing time with pure water is 4-6 minutes. Preferably, the rinsing time with tap water is 20 minutes, and the rinsing time with pure water is 5 minutes. In this embodiment, the ratio of the cleaning fluid is crucial. The cleaning fluid can effectively dissolve carbon deposits without causing rust or corrosion to the products, equipment, or pipelines. The cleaning fluid can be used to circulate and flush the pipelines through the existing cleaning equipment, ultimately achieving the effect of dissolving carbon deposits on the inner wall of the pipelines. Therefore, in this embodiment, the ratio of the cleaning fluid is as follows: Sodium hydroxide: 0.5-1.5 wt%; Industrial sodium phosphate: 1.5-2.5 wt%. Sodium tripolyphosphate: 2.5-3.5 wt%; the remainder is water. Preferably, the cleaning solution composition is as follows: sodium hydroxide: 1 wt%; industrial sodium phosphate: 2 wt%; sodium tripolyphosphate: 3 wt%; the remainder is water. In another embodiment, potassium hydroxide can be used instead of sodium hydroxide, that is, the cleaning solution composition is: potassium hydroxide 0.5-1.5 wt%; industrial sodium phosphate: 1.5-2.5 wt%; sodium tripolyphosphate: 2.5-3.5 wt%; the remainder is water. Preferably, the cleaning solution composition is: potassium hydroxide: 1 wt%; industrial sodium phosphate: 2 wt%; sodium tripolyphosphate: 3 wt%; the remainder is water. Fuel manifold vacuum back-drafting and reverse flushing: After the fuel manifold is flushed forward with cleaning fluid, it is mounted on a vibration back-drafting and flushing tester. The back-flushing equipment is started simultaneously with the vibration motor, and the main and auxiliary fuel lines of the fuel manifold are vacuumed separately. After back-drafting, reverse flushing is performed at a pressure of 4.5 kgf / cm²~5.5 kgf / cm² for 4-6 minutes. Preferably, the vacuuming time for the main and auxiliary fuel lines of the fuel manifold is 5 minutes, and the pressure during reverse flushing is 5 kgf / cm² for 5 minutes. Reverse vacuuming and reverse flushing are performed on the fuel manifold after forward flushing to prevent large carbon deposits that fell off during forward flushing from getting stuck in the manifold and ensuring complete removal of carbon deposits from the pipe. The vibration motor operates simultaneously during the vacuum back-drafting and reverse flushing of the fuel manifold, vibrating to loosen large carbon deposits stuck in the pipe, allowing them to be carried out during reverse vacuuming and flushing.

[0024] Vacuum back-drafting and back-flushing: During vacuum back-drafting, the back-drafting pipeline is connected to the main and auxiliary fuel lines of the fuel main pipe to perform reverse vacuuming on the fuel main pipe. During back-flushing, the fuel inlet pipeline is connected to the nozzle of the fuel main pipe, and the fuel outlet pipeline is connected to the main and auxiliary fuel lines of the fuel main pipe to perform reverse flushing. Through reverse flushing and back-drafting, the carbon deposits are flushed from two directions, further weakening the adhesion between the carbon deposits and the pipe wall, making them easier to peel off under the action of vibration.

[0025] In this embodiment, as Figure 2 As shown, the backflushing equipment includes a pressurized flushing section, a vibrating table, and a back-extraction section. A fuel main pipe is placed on the vibrating table. The back-extraction section is connected to the main fuel line and the auxiliary fuel line via pipelines. The main fuel line and the auxiliary fuel line are respectively connected to the nozzles of the fuel main pipe. The pressurized flushing section is connected to the nozzles of the fuel main pipe via an inlet pipeline. In this embodiment, as shown... Figure 3 As shown, there are 28 nozzles on the fuel main. During backflow and reverse flushing, the vibration motor is activated, driving the product to vibrate via a vibration table. Furthermore, to improve the installation efficiency of the fuel line and nozzles, such as... Figure 4 As shown, a hydraulic quick-connect coupling (male and female) is used to achieve plug-and-play connection, which is fast. Compared with the bolt connection method, the disassembly and assembly time of a single unit is reduced from 20 minutes to less than 5 minutes. After installation, there are 6 seals between the oil pipe and the nozzle. The first is the M16×1 end face seal of the product (guaranteed by a custom PTFE gasket). The second is the end face seal between the nut sleeve assembly and the male quick-connect coupling, which is guaranteed by a combination sealing gasket. The third is the seal of the quick (male and female) coupling itself. The fourth is the seal between the female quick-connect coupling and the connecting assembly, which is guaranteed by a combination sealing gasket. The fifth is the seal between the female quick-connect coupling and the inner conical low-pressure hose assembly, which is guaranteed by a 74° conical surface seal. The sixth is the seal between the inner conical low-pressure hose assembly and the oil supply line, which is guaranteed by a 74° conical surface seal. Preferably, the quick-connect coupling is made of stainless steel, and the connecting joints at both ends are made of high-quality carbon steel. The quick-connect coupling is obtained through commercial purchase.

[0026] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for troubleshooting carbon buildup blockage in the fuel manifold of an aircraft engine, characterized in that: Includes the following steps, Cleaning fluid circulation flushing: During flushing, add cleaning fluid into the flushing equipment, then flush with cleaning fluid first, then rinse with tap water, then rinse with pure water, and finally dry the fuel main pipe with compressed air. Vacuum back-drafting and reverse flushing of fuel main: After the fuel main is flushed in the forward direction with cleaning fluid, the fuel main is installed on the vibration back-drafting and flushing tester. The vibration motor is turned on while the back-flushing equipment is started to evacuate the main and auxiliary oil circuits of the fuel main. After the back-drafting is completed, reverse flushing is performed at a pressure of 4.5 kgf / cm2~5.5 kgf / cm2 for 4min~6min. Vacuum back-drafting and back-flushing: During vacuum back-drafting, the back-drafting pipeline is connected to the main and auxiliary fuel lines of the fuel main pipe to perform reverse vacuuming of the fuel main pipe. During back-flushing, the fuel inlet pipeline is connected to the nozzle of the fuel main pipe, and the fuel outlet pipeline is connected to the main and auxiliary fuel lines of the fuel main pipe to perform reverse flushing.

2. The method for troubleshooting carbon buildup blockage in the fuel manifold of an aircraft engine according to claim 1, characterized in that: During rinsing, the rinsing time with cleaning solution should be no less than 10 minutes, while the rinsing time with tap water should be 18 to 22 minutes, and the rinsing time with pure water should be 4 to 6 minutes.

3. The method for troubleshooting carbon buildup blockage in the fuel manifold of an aircraft engine according to claim 2, characterized in that: The rinsing time with tap water is 20 minutes, and the rinsing time with pure water is 5 minutes.

4. A method for troubleshooting carbon buildup blockage in the fuel manifold of an aircraft engine according to claim 3, characterized in that: The main and auxiliary fuel lines of the fuel main were evacuated for 5 minutes. During the reverse flushing, the pressure was 5 kgf / cm2 and maintained for 5 minutes.

5. A method for troubleshooting carbon buildup blockage in the fuel manifold of an aircraft engine according to claim 4, characterized in that: The cleaning solution is formulated as follows: sodium hydroxide: 0.5-1.5 wt%; industrial sodium phosphate: 1.5-2.5 wt%; sodium tripolyphosphate: 2.5-3.5 wt%; the remainder is water.

6. A method for troubleshooting carbon buildup blockage in the fuel manifold of an aircraft engine according to claim 4, characterized in that: The cleaning solution is formulated as follows: potassium hydroxide 0.5-1.5 wt%; industrial sodium phosphate 1.5-2.5 wt%; sodium tripolyphosphate 2.5-3.5 wt%; the remainder is water.

7. A method for troubleshooting carbon buildup blockage in the fuel manifold of an aircraft engine according to claim 5, characterized in that: The cleaning solution is formulated as follows: sodium hydroxide: 1 wt%; industrial sodium phosphate: 2 wt%; sodium tripolyphosphate: 3 wt%; the remainder is water.

8. A method for troubleshooting carbon buildup blockage in an aircraft engine fuel manifold according to claim 6, characterized in that: The cleaning solution is formulated as follows: potassium hydroxide: 1 wt%; industrial sodium phosphate: 2 wt%; sodium tripolyphosphate: 3 wt%; the remainder is water.

9. A method for troubleshooting carbon buildup blockage in the fuel manifold of an aircraft engine according to any one of claims 1 to 8, characterized in that: The backwashing equipment includes a pressurized flushing section, a vibrating table, and a back-extraction section. A fuel main pipe is placed on the vibrating table. The back-extraction section is connected to the main fuel line and the auxiliary fuel line through pipelines. The main fuel line and the auxiliary fuel line are respectively connected to the nozzles of the fuel main pipe. The pressurized flushing section is connected to the nozzles of the main pipe through an oil inlet pipeline.

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