Aero-engine fuel nozzle flow channel liquid abrasive particle flow finishing machining method

Abstract

The invention discloses an aero-engine fuel nozzle flow channel liquid abrasive flow finishing machining method which comprises the following steps that S1, a fuel nozzle is installed in an abrasive flow clamp, an upper flow equalizing grinding core is arranged in an inner hole of the fuel nozzle, and a lower flow equalizing grinding core is arranged at the lower end of the fuel nozzle; s2, liquid abrasive particle flow is used for machining the fuel nozzle, and the machining time is 40-60 s; the processing pressure is 7-8 MPa; s3, part cleaning is conducted, specifically, ultrasonic cleaning is conducted for 45-50 min, and the equipment frequency is 50-60 Hz; and S4, performance testing is conducted on the machined part. The liquid abrasive particle proportion and machining parameters suitable for the nozzle of the fuel nozzle are greatly improved, the surface quality of the nozzle and the performance of the fuel nozzle are greatly improved, the percent of pass of the spray cone angle of the fuel nozzle reaches 100%, the percent of pass of distribution unevenness is improved to 60% from 0, the surface smoothness consistency is good, and the product quality is improved. The atomization effect of the fuel nozzle is effectively improved, and the ignition performance of the fuel nozzle is guaranteed.

Description

Technical Field

[0001] The invention relates to the field of parts finishing, and more specifically to a liquid abrasive flow finishing method for a fuel nozzle flow channel of an aircraft engine. Background Art

[0002] The aircraft engine fuel nozzle is an ignition device for the engine. The fuel is sprayed out from the nozzle of the fuel nozzle. The atomization effect formed after the fuel is sprayed out determines the performance of the engine ignition and combustion, and the smoothness of the inner surface of the nozzle flow channel determines the atomization effect of the fuel after spraying. Figure 1 As shown, its structure is a contraction-expansion structure with small size, complex shape, and complex processing technology. The flow channel aperture is small, with a diameter of 0.3mm. Due to the small aperture, machining is difficult, and a tiny tool is used during cutting, which is prone to vibration, resulting in an uneven flow channel surface after processing, and tiny burrs that are invisible to the naked eye on the edge of the orifice. Such flow channel surface and orifice burrs cannot be removed manually. Even if the burrs are removed manually, the shape of the nozzle flow channel orifice will be irregular, and the arc transition at point A of the nozzle will have a great influence on the spray performance of the fuel nozzle. During manual polishing, it is difficult to ensure the consistency of the transition arc, which affects the atomization effect of the fuel sprayed from the nozzle of the fuel nozzle and is unstable, resulting in poor ignition effect of the aircraft engine.

[0003] At present, abrasive flow technology has been widely used in the field of burr removal, but the commonly used abrasive flow is solid abrasive flow, which has large abrasive particle size, high abrasive ratio, high viscosity, and high grinding force on parts. For the φ0.3 micro-hole of the fuel nozzle, solid abrasive flow can easily cause the hole to deform.

[0004] Invention patent CN115169059B discloses a method for designing and processing an engine fuel nozzle, which obtains the surface roughness of the engine fuel nozzle, obtains the abrasive specifications, processing pressure and processing time corresponding to the surface roughness, establishes a surface roughness regression model according to the surface roughness and the abrasive specifications, processing pressure and processing time corresponding to the surface roughness, and optimizes the abrasive flow polishing process parameters for processing the engine fuel nozzle using the surface roughness regression model. The invention does not provide a specific range or specific values ​​of processing parameters (such as abrasive specifications, processing pressure, processing time, etc.), resulting in the need for operators to explore and adjust parameters by themselves in actual operation, which increases the complexity and uncertainty of the operation. Summary of the invention

[0005] The present invention mainly aims at the problem that in the prior art, during the finishing operation of the flow channel in the fuel nozzle, the abrasive flow is solid, the grinding force on the parts is large, and the hole deformation is easily caused. A liquid abrasive flow finishing processing method for the flow channel of the fuel nozzle of an aircraft engine is proposed.

[0006] In view of the above technical problems, the technical solutions of the present invention are as follows:

[0007] A liquid abrasive flow finishing method for a flow channel of an aircraft engine fuel nozzle comprises the following steps:

[0008] S1: Install the fuel nozzle in the abrasive flow fixture, arrange an upper flow-averaging grinding core in the inner hole of the fuel nozzle, and arrange a lower flow-averaging grinding core at the lower end of the fuel nozzle;

[0009] S2: Use liquid abrasive flow to process the fuel nozzle, the processing time is 40 to 60 seconds, and the processing pressure is 7 to 8 MPa;

[0010] S3: Parts cleaning: Ultrasonic cleaning for 45-50 minutes, equipment frequency 50-60Hz;

[0011] S4: Perform performance test on processed parts;

[0012] The liquid abrasive flow includes solid abrasive, abrasive solution and abrasive additives. The volume fraction of the solid abrasive is 25-35%, the volume fraction of the abrasive solution is 50-60%, and the volume fraction of the abrasive additive is 5-15%.

[0013] Furthermore, the solid abrasive is one or more of aluminum oxide, silicon carbide, boron carbide, and diamond; the abrasive solution is dimethyl silicone oil; the abrasive additive includes a thickener, a dispersant, and a surfactant, and the volume fraction ratio of the thickener to the dispersant and the surfactant is 3:5:7; the thickener is an ethylene-propylene rubber polymer; the dispersant is polyethylene glycol; and the surfactant is alkylphenol polyoxyethylene ether OP-7.

[0014] Furthermore, the fuel nozzle flow channel includes a conical structure contraction section, a throat connected to the conical structure contraction section, and a nozzle expansion section connected to the throat.

[0015] Furthermore, the performance test in S4 includes appearance inspection and flow rate, spray cone angle and distribution unevenness test.

[0016] Furthermore, the solid abrasive particle size is 70-80 μm.

[0017] Furthermore, before the step S1, the process further includes: stirring the liquid abrasive flow for 20 to 30 minutes.

[0018] Furthermore, the abrasive flow fixture includes an upper mold and a lower mold, the upper and lower molds are provided with positioning circular holes and fixed by positioning pins; the upper mold is provided with an inlet, which is a circular hole evenly arranged along the circumference of the upper uniform flow grinding core; the lower mold is provided with a discharge port, which is a circular hole evenly arranged along the circumference of the lower uniform flow grinding core, and the diameter of the circular hole is consistent with the throat diameter of the fuel nozzle.

[0019] Furthermore, the upper flow-averaging grinding core is clearance-matched with the nozzle swirl chamber and the conical surface structure contraction section.

[0020] Furthermore, the lower flow-averaging grinding core is clearance-matched with the nozzle expansion section.

[0021] Furthermore, the fitting clearance is 1 / 3 of the nozzle diameter.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] The present invention proposes a liquid abrasive ratio and processing parameters suitable for the fuel nozzle nozzle, the surface quality of the nozzle and the performance of the fuel nozzle are greatly improved, the qualified rate of the spray cone angle of the fuel nozzle reaches 100%, the qualified rate of distribution unevenness is increased from 0 to 60%, and the surface finish consistency is good, which effectively improves the atomization effect of the fuel nozzle and ensures the ignition performance of the fuel nozzle. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of the fuel nozzle nozzle;

[0025] Figure 2 It is a schematic diagram of the flow path of the fuel nozzle nozzle;

[0026] Figure 3 It is the schematic diagram of the abrasive flow fixture structure;

[0027] Figure 4 It is a schematic diagram of the structure of the upper and lower flow-equalizing grinding core;

[0028] Figure 5 It is a top view of the upper mold;

[0029] Figure 6 This is a schematic diagram of the upper mold inlet structure;

[0030] Figure 7 It is a top view of the lower mold;

[0031] Figure 8 This is a schematic diagram of the structure of the lower mold outlet;

[0032] Fig. 9 A flow chart of a liquid abrasive flow finishing method for a fuel nozzle flow channel of an aircraft engine;

[0033] Among them: 1. conical structure contraction section; 2. throat; 3. nozzle expansion section; 4. upper mold; 5. fuel nozzle; 6. upper flow-averaging grinding core; 7. lower flow-averaging grinding core; 8. lower mold; 9. abrasive; 10. feed inlet; 11. feed inlet circular hole; 12. discharge port; 13. discharge port circular hole. DETAILED DESCRIPTION

[0034] In order to clearly illustrate the technical features of this solution, the present invention is described in detail below through specific implementation methods and in combination with the accompanying drawings. In the following description, many specific details are described to facilitate a full understanding of the present application, but the present application can also be implemented in other ways different from those described herein, so the protection scope 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 orientation or position relationship indicated by the terms "center", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "axial", "radial", "circumferential", etc. is based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, the features defined as "first" and "second" can explicitly or implicitly include one or more of the features. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to the specific circumstances. In this application, unless otherwise clearly specified and limited, the first feature "on" or "under" the second feature may be that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. In the description of this specification, the description of the reference terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in a suitable manner in any one or more embodiments or examples.

[0035] Example 1

[0036] The following is combined with Figure 1 ~Attached Fig. 9 This embodiment provides a liquid abrasive flow finishing method for an aircraft engine fuel nozzle flow channel.

[0037] As attached Figure 2 As shown in the figure, the nozzle flow channel of a certain aircraft engine fuel nozzle can be divided into three parts according to the size of the flow channel aperture, including a conical structure contraction section 1, a throat 2 connected to the conical structure contraction section, and a nozzle expansion section 3 connected to the throat. The aperture sizes of the three parts are quite different, which leads to uneven abrasive flow and affects the consistency of the flow channel surface finishing. In addition, the diameter of the throat 2 is only 0.3 mm, which is not conducive to the flow and grinding of the abrasive flow.

[0038] In order to effectively remove burrs and improve the performance qualification rate of fuel nozzles, this embodiment provides a liquid abrasive flow finishing method for a flow channel of an aircraft engine fuel nozzle, comprising the following steps:

[0039] S1: Install the fuel nozzle in the abrasive flow fixture, an upper flow-averaging grinding core 6 is arranged in the inner hole of the fuel nozzle 5, and a lower flow-averaging grinding core 7 is arranged at the lower end of the fuel nozzle 5;

[0040] S2: using liquid abrasive flow to process the fuel nozzle 5, the processing time is 40s; the processing pressure is 7MPa;

[0041] S3: Parts cleaning: Ultrasonic cleaning for 45 minutes, equipment frequency 50Hz, cleaning medium is hydrocarbon solution;

[0042] S4: Perform performance test on processed parts;

[0043] The liquid abrasive flow includes solid abrasive, abrasive solution and abrasive additives. The volume fraction of the solid abrasive is 25%, the volume fraction of the abrasive solution is 60%, and the volume fraction of the abrasive additive is 15%.

[0044] Because the material of the aircraft engine fuel nozzle is 9Cr18Mo, which is a martensitic stainless steel material with large plastic deformation and low thermal conductivity, it is a difficult-to-process material. In order to ensure good grinding performance, the solid abrasive is silicon carbide; the abrasive solution is dimethyl silicone oil; the abrasive additive includes a thickener, a dispersant, and a surfactant, and the volume fraction ratio of the thickener to the dispersant and the surfactant is 3:5:7; the thickener is an ethylene-propylene rubber polymer; the dispersant is polyethylene glycol; and the surfactant is alkylphenol polyoxyethylene ether OP-7.

[0045] As attached Figure 3 ~Attached Figure 8As shown, the abrasive flow fixture includes an upper mold 4 and a lower mold 8, and the upper and lower molds are provided with positioning circular holes, which are fixed by positioning pins to prevent rotational dislocation between the upper and lower molds during operation; the upper mold 4 is provided with an inlet 10, which is an inlet circular hole 11 evenly arranged along the circumference of the upper flow-equalizing grinding core 6; the lower mold 8 is provided with a discharge port 12, which is a discharge port circular hole 13 evenly arranged along the circumference of the lower flow-equalizing grinding core 7, and the diameters of the inlet circular hole 11 and the discharge circular hole 13 are consistent with the throat diameter of the fuel nozzle; a fuel nozzle 5 is placed between the upper and lower molds, an upper flow-equalizing grinding core 6 is installed in the inner hole of the nozzle, and a lower flow-equalizing grinding core 7 is installed at the lower end of the nozzle, when the abrasive with a certain pressure evenly passes through the small hole into the gap between the upper and lower grinding cores and the nozzle, a uniform flow is generated, and the burrs on the nozzle surface are polished.

[0046] The smaller the abrasive particle size, the more obvious the scratches on the surface to be processed, resulting in a decrease in the surface quality after processing. When the channel formed by the fixture and the part is small or the processed aperture is small, the particle size is too small, which will make it difficult for the abrasive to pass through, thereby reducing the grinding efficiency. For precise tiny holes such as the nozzle of a fuel nozzle, the diameter of the small hole is φ0.3mm, the surface roughness is required to be less than Ra0.4, and the solid abrasive particle size should be 70μm.

[0047] The performance test in S4 includes visual inspection of the fuel nozzle and flow rate, spray cone angle and distribution unevenness test.

[0048] Example 2

[0049] The following is combined with Figure 1 ~Attached Fig. 9 This embodiment provides a liquid abrasive flow finishing method for a fuel nozzle flow channel of an aircraft engine, comprising the following steps:

[0050] S1: Install the fuel nozzle 5 in the abrasive flow fixture, an upper flow-averaging grinding core 6 is arranged in the inner hole of the fuel nozzle 5, and a lower flow-averaging grinding core 7 is arranged at the lower end of the fuel nozzle 5;

[0051] S2: using liquid abrasive flow to process the fuel nozzle 5, the processing time is 60s and the processing pressure is 8MPa;

[0052] S3: Parts cleaning: Ultrasonic cleaning for 50 minutes, equipment frequency 60Hz, cleaning medium is hydrocarbon solution;

[0053] S4: Perform performance test on processed parts;

[0054] Furthermore, before the step S1, the process further includes: stirring the liquid abrasive flow for 20 to 30 minutes to allow the abrasive to fully circulate.

[0055] The liquid abrasive flow includes solid abrasive, abrasive solution and abrasive additives. The volume fraction of the solid abrasive is 35%, the volume fraction of the abrasive solution is 50%, and the volume fraction of the abrasive additive is 15%.

[0056] The solid abrasive is silicon carbide; the abrasive solution is dimethyl silicone oil; the abrasive additives include a thickener, a dispersant, and a surfactant, and the volume fraction ratio of the thickener to the dispersant and the surfactant is 3:5:7; the thickener is an ethylene-propylene rubber polymer; the dispersant is polyethylene glycol; and the surfactant is alkylphenol polyoxyethylene ether OP-7.

[0057] The particle size of the solid abrasive is selected to be 80 μm.

[0058] Example 3

[0059] The following is combined with Figure 1 ~Attached Fig. 9 This embodiment provides a liquid abrasive flow finishing method for a fuel nozzle flow channel of an aircraft engine, comprising the following steps:

[0060] S1: Install the fuel nozzle 5 in the abrasive flow fixture, an upper flow-averaging grinding core 6 is arranged in the inner hole of the fuel nozzle 5, and a lower flow-averaging grinding core 7 is arranged at the lower end of the fuel nozzle 5;

[0061] S2: using liquid abrasive flow to process the fuel nozzle 5, the processing time is 50s; the processing pressure is 7.5MPa;

[0062] S3: Parts cleaning: Ultrasonic cleaning for 48 minutes, equipment frequency 55Hz, cleaning medium is hydrocarbon solution;

[0063] S4: Perform performance test on processed parts;

[0064] The liquid abrasive flow includes solid abrasive, abrasive solution and abrasive additives. The volume fraction of the solid abrasive is 30%, the volume fraction of the abrasive solution is 55%, and the volume fraction of the abrasive additive is 15%.

[0065] The solid abrasive is silicon carbide; the abrasive solution is dimethyl silicone oil; the abrasive additives include a thickener, a dispersant, and a surfactant, and the volume fraction ratio of the thickener to the dispersant and the surfactant is 3:5:7; the thickener is an ethylene-propylene rubber polymer; the dispersant is polyethylene glycol; and the surfactant is alkylphenol polyoxyethylene ether OP-7.

[0066] The particle size of the solid abrasive is selected to be 75 μm.

[0067] Furthermore, the upper flow-averaging grinding core 6 is gap-matched with the nozzle swirl chamber and the conical structure contraction section, and the lower flow-averaging grinding core 7 is gap-matched with the nozzle expansion section. The matching gap is 1 / 3 of the nozzle diameter, which allows the abrasive flow to fully contact the inner cavity and improves the utilization rate of the abrasive.

[0068] For each embodiment, 6 parts from the same batch are set for processing test

[0069] The parts before processing in Examples 1, 2 and 3 were tested for performance, and the test results are shown in the following table:

[0070] Table 1 Flow rate experimental data before liquid abrasive flow polishing

[0071]

[0072]

[0073] The performance tests were performed on the processed parts in Examples 1, 2 and 3, and the test results are shown in the following table:

[0074] Table 2 Flow rate experimental data after liquid abrasive flow polishing

[0075]

[0076] The performance indicators of the fuel nozzle are flow rate 91~97g / min, spray cone angle 70°±5°, and distribution unevenness not more than 30%. By comparing the data before and after abrasive flow processing, the flow rate of the fuel nozzle increased after abrasive flow processing, and the increase was between 0.9~1.7g / min. The increased nozzle flow rate is still within the qualified range. Due to the small size of the nozzle, it is difficult to achieve a smooth transition between the oil outlet and the inner cone surface, resulting in the spray cone angle of the processed nozzle cannot be fully opened, and the angle is small. After abrasive flow processing, the transition is evenly ground to form a uniform transition R, and the spray cone angle of the nozzle also increases. The cone angle increases by about 13°, all within the required range, and the qualified rate of the spray cone angle reaches 100%. Regarding the uneven distribution of the spray, before abrasive flow processing, the burrs in the center hole had a greater impact on the uneven distribution, so the uneven distribution was poor. After abrasive flow processing, the internal burrs were removed and the surface quality was improved, the uneven distribution was greatly improved, and the pass rate of the uneven distribution of the fuel nozzle was increased from 0 to 60%. The uneven distribution of some nozzles still exceeded the requirements. This is because the nozzle is composed of multiple parts. The uneven distribution is not only related to the central flow channel of the auxiliary nozzle, but also to the swirl groove of the swirler.

[0077] The embodiments are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A liquid abrasive flow finishing method for a fuel nozzle flow channel of an aircraft engine, characterized in that: The following steps are involved: S1: Install the fuel nozzle in the abrasive flow fixture, arrange an upper flow-averaging grinding core in the inner hole of the fuel nozzle, and arrange a lower flow-averaging grinding core at the lower end of the fuel nozzle; S2: Use liquid abrasive flow to process the fuel nozzle, the processing time is 40 to 60 seconds, and the processing pressure is 7 to 8 MPa; S3: Parts cleaning: Ultrasonic cleaning for 45-50 minutes, equipment frequency 50-60Hz; S4: Perform performance test on processed parts; The liquid abrasive flow includes solid abrasive, abrasive solution and abrasive additives. The volume fraction of the solid abrasive is 25-35%, the volume fraction of the abrasive solution is 50-60%, and the volume fraction of the abrasive additive is 5-15%.

2. The method for liquid abrasive flow finishing of a fuel nozzle flow channel of an aircraft engine according to claim 1, characterized in that: The solid abrasive is one or more of aluminum oxide, silicon carbide, boron carbide, and diamond; the abrasive solution is dimethyl silicone oil; the abrasive additive includes a thickener, a dispersant, and a surfactant, and the volume fraction ratio of the thickener to the dispersant and the surfactant is 3:5:7; the thickener is an ethylene-propylene rubber polymer; the dispersant is polyethylene glycol; and the surfactant is alkylphenol polyoxyethylene ether OP-7.

3. The method for liquid abrasive flow finishing of a fuel nozzle flow channel of an aircraft engine according to claim 1, characterized in that: The fuel nozzle flow channel comprises a conical surface structure contraction section, a throat connected to the conical surface structure contraction section, and a nozzle expansion section connected to the throat.

4. The method for liquid abrasive flow finishing of a fuel nozzle flow channel of an aircraft engine according to claim 1, characterized in that: The performance test in S4 includes appearance inspection and flow rate, spray cone angle and distribution unevenness test.

5. The method for liquid abrasive flow finishing of a fuel nozzle flow channel of an aircraft engine according to claim 1, characterized in that: The solid abrasive particle size is 70-80 μm.

6. The method for liquid abrasive flow finishing of a fuel nozzle flow channel of an aircraft engine according to claim 1, characterized in that: Before the step S1, the method further includes: stirring the liquid abrasive flow for 20 to 30 minutes.

7. The method for liquid abrasive flow finishing of a fuel nozzle flow channel of an aircraft engine according to claim 1, characterized in that: The abrasive flow fixture includes an upper mold and a lower mold, the upper and lower molds are provided with positioning circular holes and fixed by positioning pins; the upper mold is provided with an inlet, which is a circular hole evenly arranged along the circumference of the upper uniform flow grinding core; the lower mold is provided with a discharge port, which is a circular hole evenly arranged along the circumference of the lower uniform flow grinding core, and the diameter of the circular hole is consistent with the throat diameter of the fuel nozzle.

8. The method for liquid abrasive flow finishing of a fuel nozzle flow channel of an aircraft engine according to claim 1, characterized in that: The upper flow-averaging grinding core is clearance-matched with the nozzle swirl chamber and the conical surface structure contraction section.

9. The method for liquid abrasive flow finishing of a fuel nozzle flow channel of an aircraft engine according to claim 1, characterized in that: The lower flow-averaging grinding core is clearance-matched with the nozzle expansion section.

10. A liquid abrasive flow finishing method for a fuel nozzle flow channel of an aircraft engine according to claim 8 or 9, characterized in that: The fitting clearance is 1 / 3 of the nozzle diameter.

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