A liquid abrasive flow finishing method for a fuel nozzle flow channel of an aircraft engine

Abstract

The present invention discloses a liquid abrasive flow finishing method for the flow channel of an aircraft engine fuel nozzle. The method comprises the following steps: S1: installing the fuel nozzle in an abrasive flow fixture, disposing an upper flow-uniform grinding core in the inner hole of the fuel nozzle, and disposing a lower flow-uniform grinding core at the lower end of the fuel nozzle; S2: machining the fuel nozzle using a liquid abrasive flow, with a machining time of 40 to 60 seconds and a machining pressure of 7 to 8 MPa; S3: parts cleaning: ultrasonic cleaning for 45 to 50 minutes, with an equipment frequency of 50 to 60 Hz; S4: performance testing of the machined parts. The present invention proposes a liquid abrasive ratio and processing parameters suitable for the fuel nozzle orifice, which significantly improves the surface quality of the nozzle orifice and the performance of the fuel nozzle. The qualified rate of the fuel nozzle spray cone angle reaches 100%, the qualified rate of distribution unevenness increases from 0 to 60%, and the surface finishing consistency is good, effectively improving the atomization effect of the fuel nozzle and ensuring the ignition performance of the fuel nozzle.

Description

Technical Field

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

[0002] The fuel nozzle of an aircraft engine is an ignition device for the engine. The fuel is ejected from the nozzle of the fuel nozzle. The atomization effect after the fuel is ejected determines the performance of the engine ignition and combustion. The smoothness of the inner surface of the nozzle flow channel determines the atomization effect of the fuel after the fuel is ejected. 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. 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] Abrasive flow technology is currently widely used for deburring. However, the commonly used abrasive flow is solid abrasive flow, which has large abrasive particle size, a high abrasive content, high viscosity, and a high grinding force on parts. For the tiny 0.3mm diameter orifice of a fuel nozzle, solid abrasive flow can easily cause orifice deformation.

[0004] Invention patent CN115169059B discloses a method for designing and processing an engine fuel nozzle. This method obtains the surface roughness of the engine fuel nozzle, determines the abrasive grain size, processing pressure, and processing time corresponding to the surface roughness, establishes a surface roughness regression model based on the surface roughness and the corresponding abrasive grain size, processing pressure, and processing time, and uses the surface roughness regression model to optimize the abrasive flow polishing process parameters for processing the engine fuel nozzle. This invention does not provide specific ranges or values ​​for processing parameters (such as abrasive grain size, processing pressure, and processing time). Consequently, in actual operation, operators must independently explore and adjust the parameters, increasing operational complexity and uncertainty. 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 orifice is easily deformed. 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 an aircraft engine fuel nozzle flow channel comprises the following steps:

[0008] S1: Install the fuel nozzle in the abrasive flow fixture, set an upper flow-averaging grinding core in the inner hole of the fuel nozzle, and set 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 40~60s; the processing pressure is 7~8MPa;

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

[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 particle size of the solid abrasive is 70-80 μm.

[0017] Furthermore, before 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, and 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 diameter of the throat of the fuel nozzle.

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

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

[0021] Furthermore, the fitting gap 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 nozzle of a fuel 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 This is a schematic diagram of the fuel nozzle nozzle;

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

[0026] Figure 3 Schematic diagram of the abrasive flow fixture structure;

[0027] Figure 4 Schematic diagram of the upper and lower flow-equalizing grinding core structure;

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

[0029] Figure 6 Schematic diagram of the upper mold inlet structure;

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

[0031] Figure 8 Schematic diagram of the lower mold discharge port structure;

[0032] Figure 9 This is a flow chart of a liquid abrasive flow finishing method for an aircraft engine fuel nozzle flow channel;

[0033] Among them: 1. Conical structure contraction section; 2. Throat; 3. Nozzle expansion section; 4. Upper mold; 5. Fuel nozzle; 6. Upper uniform flow grinding core; 7. Lower uniform flow grinding core; 8. Lower mold; 9. Abrasive; 10. Feed port; 11. Feed port 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 conjunction with the accompanying drawings. Many specific details are described in the following description to facilitate a full understanding of the present application. However, the present application can also be implemented in other ways different from those described herein. Therefore, the scope of protection of the present application is not limited by the specific embodiments disclosed below. In addition, in the description of the present application, it should be understood that the terms "center", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "axial", "radial", "circumferential" and the like indicate the orientation or position relationship based on the orientation or position relationship shown in the accompanying drawings. They are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation. Therefore, they should not be understood as limiting the present application. In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly indicate the number of technical features indicated. Therefore, features defined as "first" and "second" can explicitly or implicitly include one or more of such 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 expressly 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 with reference to the 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 an appropriate manner in any one or more embodiments or examples.

[0035] Example 1

[0036] The following is combined with Figure 1 ~Attached Figure 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 section 2 connected to the conical structure contraction section, and a nozzle expansion section 3 connected to the throat. The large difference in the aperture sizes of the three parts leads to uneven abrasive flow, affecting the consistency of the flow channel surface finishing. In addition, the diameter of the throat section 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 the flow channel of an aircraft engine fuel nozzle, comprising the following steps:

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

[0040] S2: The fuel nozzle 5 is processed using a liquid abrasive flow, with a processing time of 40 seconds and a processing pressure of 7 MPa;

[0041] S3: Parts cleaning: Ultrasonic cleaning for 45 minutes, equipment frequency 50Hz, cleaning medium is hydrocarbon solution; S4: Performance test of processed parts;

[0042] The liquid abrasive flow includes solid abrasive particles, an abrasive solution and an abrasive additive. The volume fraction of the solid abrasive particles is 25%, the volume fraction of the abrasive solution is 60%, and the volume fraction of the abrasive additive is 15%.

[0043] Because the material of the aircraft engine fuel nozzle is 9Cr18Mo, which is a martensitic stainless steel material, the material has large plastic deformation and low thermal conductivity, and is a difficult-to-process material. In order to ensure good grinding performance, the solid abrasive is selected from 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.

[0044] As attached Figure 3 ~Attached Figure 8As shown, the abrasive flow fixture includes an upper mold 4 and a lower mold 8. The upper and lower molds are provided with positioning circular holes and 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 uniform flow grinding core 6; the lower mold 8 is provided with a discharge port 12, which is a discharge circular hole 13 evenly arranged along the circumference of the lower uniform flow 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 uniform flow grinding core 6 is installed in the inner hole of the nozzle, and a lower uniform flow 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 to perform a finishing operation on the burrs on the nozzle surface.

[0045] The smaller the abrasive particle size, the more obvious the scratches on the surface to be machined, resulting in a decrease in the surface quality after machining. When the channel formed by the fixture and the part is small or the machining aperture is small, the particle size is too small, which makes 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.

[0046] The performance test in S4 includes visual inspection of the fuel nozzle and flow rate, spray cone angle and distribution unevenness test.

[0047] Example 2

[0048] The following is combined with Figure 1 ~Attached Figure 9 This embodiment provides a liquid abrasive flow finishing method for an aircraft engine fuel nozzle flow channel, comprising the following steps:

[0049] S1: Install the fuel nozzle 5 in the abrasive flow fixture, and set an upper flow-uniform grinding core 6 in the inner hole of the fuel nozzle 5 and a lower flow-uniform grinding core 7 at the lower end of the fuel nozzle 5;

[0050] S2: The fuel nozzle 5 is processed using a liquid abrasive flow, the processing time is 60s, and the processing pressure is 8MPa;

[0051] S3: Parts cleaning: ultrasonic cleaning for 50 minutes, equipment frequency 60Hz, cleaning medium is hydrocarbon solution; S4: Performance test of processed parts;

[0052] 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.

[0053] The liquid abrasive flow includes solid abrasive particles, an abrasive solution and an abrasive additive. The volume fraction of the solid abrasive particles is 35%, the volume fraction of the abrasive solution is 50%, and the volume fraction of the abrasive additive is 15%.

[0054] 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.

[0055] The particle size of the solid abrasive is selected to be 80 μm.

[0056] Example 3

[0057] The following is combined with Figure 1 ~Attached Figure 9 This embodiment provides a liquid abrasive flow finishing method for an aircraft engine fuel nozzle flow channel, comprising the following steps:

[0058] S1: Install the fuel nozzle 5 in the abrasive flow fixture, and set an upper flow-uniform grinding core 6 in the inner hole of the fuel nozzle 5 and a lower flow-uniform grinding core 7 at the lower end of the fuel nozzle 5;

[0059] S2: The fuel nozzle 5 is processed using a liquid abrasive flow, the processing time is 50 seconds, and the processing pressure is 7.5 MPa;

[0060] S3: Parts cleaning: Ultrasonic cleaning for 48 minutes, equipment frequency 55Hz, cleaning medium is hydrocarbon solution; S4: Performance test of processed parts;

[0061] The liquid abrasive flow includes solid abrasive particles, an abrasive solution and an abrasive additive. The volume fraction of the solid abrasive particles is 30%, the volume fraction of the abrasive solution is 55%, and the volume fraction of the abrasive additive is 15%.

[0062] 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.

[0063] The particle size of the solid abrasive is selected to be 75 μm.

[0064] Furthermore, the upper flow-uniform grinding core 6 is clearance-matched with the nozzle swirl chamber and the conical structure contraction section, and the lower flow-uniform grinding core 7 is clearance-matched with the nozzle expansion section. The clearance 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.

[0065] For each embodiment, 6 parts from the same batch were set up for processing test.

[0066] The parts before processing in Examples 1, 2 and 3 were subjected to performance tests, and the test results are shown in the following table:

[0067] Table 1 Flow rate experimental data before liquid abrasive flow polishing

[0068]

[0069] The performance tests were conducted on the machined parts in Examples 1, 2 and 3. The test results are shown in the following table:

[0070] Table 2 Flow rate experimental data after liquid abrasive flow polishing

[0071]

[0072] The performance indicators of this fuel nozzle are flow rate 91~97g / min, spray cone angle 70°±5°, and distribution unevenness no 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, with the increase ranging from 0.9 to 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 unable to fully open and the angle being small. After abrasive flow processing, the transition point is evenly ground to form a uniform transition R, and the spray cone angle of the nozzle also increases accordingly. The cone angle increases by about 13°, all within the required range, and the qualified rate of the spray cone angle reaches 100%. Regarding spray unevenness, before AFM, burrs within the center hole significantly impacted the distribution, resulting in poor distribution unevenness. After AFM, internal burrs were removed and surface quality improved, significantly boosting distribution unevenness. The pass rate for fuel nozzle distribution unevenness increased from 0 to 60%. However, some nozzles still exhibited distribution unevenness exceeding requirements. This is because the nozzles are composed of multiple components, and distribution unevenness is related not only to the central flow channel of the secondary nozzle but also to the swirl groove of the swirler.

[0073] The embodiments are provided merely to illustrate the present invention and are not intended to limit the embodiments of the present invention. Those skilled in the art will appreciate that other variations or modifications may be made based on the above description. It is not necessary and impossible to enumerate all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention are intended to be included within the scope of protection of the claims.

Claims

1. A liquid abrasive flow finishing method for an aircraft engine fuel nozzle flow channel, characterized in that: The following steps are involved: S1: Install the fuel nozzle in the abrasive flow fixture, set an upper flow-averaging grinding core in the inner hole of the fuel nozzle, and set 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 40~60s; the processing pressure is 7~8MPa; S3: Parts cleaning: Ultrasonic cleaning for 45-50 minutes, equipment frequency 50-60 Hz; S4: Perform performance test on processed parts; The liquid abrasive flow includes solid abrasive particles, an abrasive solution and an abrasive additive, wherein the volume fraction of the solid abrasive particles is 25-35%, the volume fraction of the abrasive solution is 50-60%, and the volume fraction of the abrasive additive is 5-15%. The solid abrasive particles are 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 an alkylphenol polyoxyethylene ether OP-7.

2. The liquid abrasive flow finishing method for the flow channel of an aircraft engine fuel nozzle according to claim 1, characterized in that: The fuel nozzle flow channel includes 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.

3. The liquid abrasive flow finishing method for the flow channel of an aircraft engine fuel nozzle 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.

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 particle size of the solid abrasive is 70-80 μm.

5. The liquid abrasive flow finishing method for the flow channel of an aircraft engine fuel nozzle 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.

6. The method for liquid abrasive flow finishing of a fuel nozzle channel of an aircraft engine according to claim 1, characterized in that: The abrasive flow fixture includes an upper mold and a lower mold, and 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 diameter of the throat of the fuel nozzle.

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

8. The method for liquid abrasive flow finishing of a fuel nozzle 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.

9. A liquid abrasive flow finishing method for an aircraft engine fuel nozzle flow channel according to claim 7 or 8, characterized in that: The fitting gap is 1 / 3 of the nozzle diameter.

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