A machining method for high-precision fuel flow channel of an aero-engine fuel nozzle swirler

Abstract

The application relates to the technical field of precision machining and aero-engine manufacturing, and discloses a machining method for a high-precision fuel flow channel of an aero-engine fuel nozzle swirler, which comprises the following steps: preliminarily machining a bar material to obtain a semi-finished swirler with a stepped conical surface, and then opening a plurality of uniformly distributed rectangular fuel flow channels on the stepped conical surface. The application can avoid the problems of the remelted layer which is difficult to remove, poor precision and the rectangular fuel flow channel bottom surface in a semicircular shape and a "bell mouth" shape caused by the traditional wire cutting and electric spark machining process, effectively solve the problems of poor precision of the electric machining process and the shape not meeting the requirements, and guarantee the shape requirements and size precision of the extremely thin and high-precision fuel flow channel of the aero-engine fuel nozzle swirler.

Description

Technical Field

[0001] This invention relates to the fields of precision machining and aero-engine manufacturing technology. Specifically, it relates to a method for machining high-precision fuel flow channels in aero-engine fuel nozzle swirlers. Background Technology

[0002] In aero engines, swirlers are primarily used in the fuel supply system, especially in the fuel mixing and atomization process. They utilize the principle of rotating fluid to ensure thorough mixing of fuel and air, guaranteeing effective fuel atomization within the engine combustion chamber, thereby improving combustion efficiency and reducing emissions. Swirlers in aero engines are typically installed in front of the fuel nozzles, and their main function is to disperse fuel into small droplets using the centrifugal force generated by the rotating airflow. This increases the contact area between fuel and air, ensuring more complete and uniform combustion.

[0003] Existing processes for machining ultra-fine, high-precision fuel channels generally employ electrical discharge machining (EDM), specifically wire cutting and electrical discharge machining (EDM). EDM can result in a remelted layer on the machined surface, which is difficult to remove and leads to excessive precision tolerances. Wire cutting can cause the fuel channel surface to be semi-circular. EDM can result in a "trumpet-shaped" fuel channel. All of these drawbacks fail to meet the requirements for the shape and dimensions of ultra-fine, high-precision fuel channels, affecting the fuel injection volume and atomization cone angle of aero-engine fuel nozzles. Summary of the Invention

[0004] The purpose of this invention is to provide a high-precision fuel flow channel processing method for aero-engine fuel nozzle swirlers, solving problems such as the presence of a difficult-to-remove remelted layer and poor precision on the processed surface due to conventional processing techniques; and the semi-circular bottom surface and "trumpet mouth" shape of the rectangular fuel flow channel.

[0005] This invention is achieved through the following technical solution: a method for processing high-precision fuel flow channels in an aero-engine fuel nozzle swirler, comprising preliminary processing of a bar stock to obtain a semi-finished swirler with a stepped conical surface, and then opening multiple uniformly distributed rectangular fuel flow channels on the stepped conical surface; specifically including: Step S1: Clamp the selected bar material on the machine tool, and use the machine tool to process the bar material in sequence into four aspects: the first cylindrical surface, the first conical surface, the second cylindrical surface, the second conical surface, the oil inlet plane, and the oil guide conical surface to obtain a semi-finished hydrocyclone. Step S2: Use a clamping fixture to clamp the semi-finished hydrocyclone, and then clamp the fixture on a five-axis machining center; Step S3: The five-axis machining center uses a cutting tool to machine a rectangular fuel flow channel on the semi-finished hydrocyclone in a roughing-finishing manner. The starting end of the rectangular fuel flow channel is located on the oil inlet plane, and the ending end is located on the first cylindrical surface.

[0006] To better realize the present invention, the roughing-finishing method in step 3 is further described as follows: during roughing, a layered processing method is adopted, with the processing depth of each layer controlled at 0.3mm; then, a semi-finishing process is carried out using the same layered processing method, with the processing depth of each layer controlled at 0.1mm, leaving a margin of 0.01mm on the sides and bottom of the rectangular fuel flow channel; finally, the finishing process is carried out, which requires that the finishing process be completed in one go.

[0007] To better realize the present invention, further, in step S3, the distance from the side of the rectangular fuel flow channel to the axis of the hydrocyclone is 0.8±0.05mm, the distance from the starting end of the rectangular fuel flow channel to the axis of the hydrocyclone is 0.79±0.05mm, the width of the rectangular fuel flow channel is 0.26±0.01mm, the angle formed by the bottom surface of the rectangular fuel flow channel and the axis of the hydrocyclone is 143.2°±10′, the maximum depth of the rectangular fuel flow channel is 0.41mm, and the total length is 2.37mm.

[0008] To better realize the present invention, in step S3, the cutting length of the tool is 0.05-0.1 mm longer than the depth of the rectangular fuel flow channel.

[0009] To better realize the present invention, the ratio of the cutting length to the diameter of the tool is further 2.5:1.

[0010] To better realize the present invention, the diameter of the cutting tool is 0.2 mm and the cutting length is 0.5 mm.

[0011] To better realize the present invention, the clamping positioning accuracy of the clamping fixture in step S2 is further 0.0005mm.

[0012] To better realize the present invention, the material of the bar stock in step S1 is 9Cr18Mo, and after quenching and tempering, the hardness is ≥50HRC.

[0013] Compared with the prior art, the present invention has the following advantages and beneficial effects: (1) This invention can avoid the problems caused by traditional wire cutting and electrical discharge machining processes, such as the presence of a difficult-to-remove remelted layer and poor precision on the machined surface; as well as the semi-circular bottom surface and "trumpet mouth" shape of the rectangular fuel flow channel; it can effectively solve the adverse factors such as poor precision and non-compliance of the shape in electrical discharge machining process, and can ensure the extremely fine and high-precision fuel flow channel shape and dimensional accuracy of the aero-engine fuel nozzle vortex. (2) By setting a special tool size, the present invention can speed up the production efficiency of hydrocyclones and prevent the tool from chipping. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the process of the present invention.

[0015] Figure 2 This is a schematic diagram of the overall structure of the hydrocyclone.

[0016] Figure 3 This is a frontal view of the overall structure of the hydrocyclone.

[0017] Figure 4 This is a schematic diagram of the overall structure of the hydrocyclone from the left view.

[0018] Figure 5 This is a frontal sectional view of the overall structure of the hydrocyclone.

[0019] Figure 6 This is a schematic diagram of the cutting tool structure.

[0020] Wherein: 101 - four aspects; 102 - first cylindrical surface; 103 - first conical surface; 104 - second conical surface; 105 - oil inlet plane; 106 - oil guide conical surface; 107 - second cylindrical surface; 108 - rectangular fuel flow channel; 11 - cutting tool. Detailed Implementation

[0021] 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 a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0022] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" 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] Example 1: This embodiment provides a method for machining high-precision fuel flow channels in an aero-engine fuel nozzle swirler, specifically as follows: Figures 1-6As shown, the process includes preliminary processing of the bar stock to obtain a semi-finished hydrocyclone with a stepped conical surface, followed by the opening of multiple evenly distributed rectangular fuel flow channels 108 on the stepped conical surface; in this embodiment, four rectangular fuel flow channels 108 are specifically selected. The entire hydrocyclone has the structural characteristics of a rotating body, with a maximum diameter of 5.4 mm, a minimum diameter of 0.88 mm, and a total length of 9.48 mm, specifically including: Step S1: Clamp the selected bar stock on the machine tool, and use the machine tool to process the bar stock in sequence to form four sides 101, the first cylindrical surface 102, the first conical surface 103, the second cylindrical surface 107, the second conical surface 104, the oil inlet plane 105, and the oil guide conical surface 106, to obtain a semi-finished hydrocyclone; the processing technology of the four sides 101 can be CNC milling or wire cutting, with rounded corners, and the symmetry requirement of its form and position tolerance is 0.01mm; Step S2: Use a clamping fixture to clamp the semi-finished hydrocyclone, and then clamp the fixture on a five-axis machining center. The clamping and positioning accuracy of the clamping fixture is 0.0005mm. Step S3: The five-axis machining center uses the tool 11 to machine a rectangular fuel flow channel 108 on the semi-finished hydrocyclone in a roughing and finishing manner. The starting end of the rectangular fuel flow channel 108 is located on the oil inlet plane 105, and the ending end is located on the first cylindrical surface 102. The machining is then completed.

[0024] When the cyclone separator is installed in the nozzle, the second cylindrical surface 107 is inserted into the nozzle, and the second conical surface 104 cooperates with the fuel outlet in the nozzle to form a sealing surface, ensuring that the fuel can only flow through the rectangular fuel flow channel 108. The oil guide cone surface 106 is used to control the fuel flow rate into the rectangular fuel flow channel 108. The oil guide cone surface 106 cooperates with the nozzle to form the first flow channel, where the fuel is accelerated and rotated, and then enters the second flow channel composed of multiple rectangular fuel flow channels 108, and then atomizes and sprays out.

[0025] The above processing method avoids the problems caused by wire cutting and electrical discharge machining, such as the difficult-to-remove remelted layer and out-of-tolerance precision on the machined surface; as well as the semi-circular and "trumpet mouth" shape of the bottom surface of the rectangular fuel flow channel 108. It can effectively solve the adverse factors such as poor precision and non-compliance with shape requirements of electrical discharge machining, and can ensure the extremely fine and high-precision fuel flow channel shape requirements and dimensional accuracy of the aero-engine fuel nozzle vortex.

[0026] Example 2: This embodiment further expands upon the above embodiment. The roughing-finishing method in step 3 specifically involves: roughing in layers, with each layer's depth controlled at 0.3mm; followed by semi-finishing in layers, with each layer's depth controlled at 0.1mm, leaving a 0.01mm allowance on the sides and bottom of the rectangular fuel flow channel 108; finally, finishing is performed, requiring a single, complete machining operation. This method reduces the contact stress between the tool 11 and the hydrocyclone, preventing damage to the tool 11, while simultaneously balancing machining speed and quality.

[0027] The other parts of this embodiment are the same as those in the above embodiments, and will not be described again.

[0028] Example 3: This embodiment further extends the above embodiment, specifically as follows: Figure 4 As shown, in step S3, the final distance between the side of the rectangular fuel flow channel 108 and the axis of the hydrocyclone is 0.8±0.05mm, the distance between the starting end of the rectangular fuel flow channel 108 and the axis of the hydrocyclone is 0.79±0.05mm, the width of the rectangular fuel flow channel 108 is 0.26±0.01mm, the angle between the bottom surface of the rectangular fuel flow channel 108 and the axis of the hydrocyclone is 143.2°±10′, the maximum depth of the rectangular fuel flow channel 108 is 0.41mm, and the total length is 2.37mm.

[0029] The other parts of this embodiment are the same as those in the above embodiments, and will not be described again.

[0030] Example 4: This embodiment further extends the above embodiment. Since the diameter of the tool 11 needs to be smaller than the width of the rectangular fuel flow channel 108, and its cutting length needs to be greater than the depth of the rectangular fuel flow channel 108 in order to complete the machining in one go and ensure sufficiently high precision, the cutting length of the tool 11 in step S3 is 0.05-0.1mm longer than the depth of the rectangular fuel flow channel 108. The ratio of the cutting length to the diameter of the tool 11 is 2.5:1. Specifically, the diameter of the tool 11 is 0.2mm and the cutting length is 0.5mm.

[0031] The other parts of this embodiment are the same as those in the above embodiments, and will not be described again.

[0032] Example 5: This embodiment further expands upon the above embodiment. The material of the bar stock in step S1 is 9Cr18Mo, which is a high-carbon chromium martensitic stainless steel. After quenching and tempering, the hardness is ≥50HRC, which has high hardness and wear resistance. It has small deformation, good dimensional stability, and strong corrosion resistance, which can ensure that the hydrocyclone works stably under the working parameters.

[0033] The other parts of this embodiment are the same as those in the above embodiments, and will not be described again.

[0034] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications or equivalent changes made to the above embodiments based on the technical essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. A method for machining a high-precision fuel flow channel in an aero-engine fuel nozzle swirler, characterized in that, This includes preliminary processing of bar stock to obtain a semi-finished hydrocyclone with a stepped conical surface, followed by the creation of multiple uniformly distributed rectangular fuel flow channels (108) on the stepped conical surface; specifically including: Step S1: The selected bar material is clamped on the machine tool, and the machine tool is used to process the bar material in sequence to form four aspects (101), the first cylindrical surface (102), the first conical surface (103), the second cylindrical surface (107), the second conical surface (104), the oil inlet surface (105), and the oil guide conical surface (106) to obtain a semi-finished hydrocyclone. Step S2: Use a clamping fixture to clamp the semi-finished hydrocyclone, and then clamp the fixture on a five-axis machining center. Step S3: The five-axis machining center uses a cutting tool (11) to machine a rectangular fuel flow channel (108) on the semi-finished hydrocyclone in a roughing and finishing manner. The starting end of the rectangular fuel flow channel (108) is located on the oil inlet plane (105), and the ending end is located on the first cylindrical surface (102). The roughing-finishing method in step S3 is as follows: during roughing, a layered processing method is used, with the processing depth of each layer controlled at 0.3mm; then, a semi-finishing process is also performed using a layered processing method, with the processing depth of each layer controlled at 0.1mm, leaving a allowance of 0.01mm on the sides and bottom of the rectangular fuel flow channel (108); finally, the finishing process is performed, which requires that the finishing be completed in one go. In step S3, the final rectangular fuel flow channel (108) has a side distance of 0.8 ± 0.05 mm from the axis of the hydrocyclone, a starting end distance of 0.79 ± 0.05 mm from the axis of the hydrocyclone, a width of 0.26 ± 0.01 mm, an angle of 143.2° ± 10′ between the bottom surface of the rectangular fuel flow channel (108) and the axis of the hydrocyclone, a maximum depth of 0.41 mm, and a total length of 2.37 mm.

2. The method for machining a high-precision fuel flow channel for an aero-engine fuel nozzle swirler according to claim 1, characterized in that: The cutting length of the cutter (11) in step S3 is 0.05-0.1 mm longer than the depth of the rectangular fuel flow channel (108).

3. The method for machining a high-precision fuel flow channel for an aero-engine fuel nozzle swirler according to claim 2, characterized in that: The ratio of the blade length to the diameter of the cutting tool (11) is 2.5:

1.

4. The method for machining a high-precision fuel flow channel for an aero-engine fuel nozzle swirler according to claim 3, characterized in that: The diameter of the cutting tool (11) is 0.2 mm and the blade length is 0.5 mm.

5. The method for machining a high-precision fuel flow channel for an aero-engine fuel nozzle swirler according to claim 1, characterized in that: The clamping and positioning accuracy of the clamping fixture in step S2 is 0.0005mm.

6. The method for machining a high-precision fuel flow channel for an aero-engine fuel nozzle swirler according to claim 1, characterized in that: The bar material mentioned in step S1 is 9Cr18Mo, and after quenching and tempering, its hardness is ≥50HRC.

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