A machining process for the inner curved surface of a wind tunnel rotating nozzle

Abstract

This invention belongs to the field of internal curved surface machining, and provides a machining process for the internal curved surface of a wind tunnel rotating nozzle. The process includes: assembling and positioning a front nozzle and a rear nozzle, wherein the diameter of the front end of the front nozzle and the rear nozzle is larger than the diameter of the rear end; continuously precision machining from the larger end of the front nozzle towards the smaller end, precision machining to a predetermined distance inward from the larger end of the rear nozzle, while simultaneously machining a straight edge; disassembling the front nozzle and assembling and positioning the next nozzle segment at the smaller end of the rear nozzle; finding the straight edge as the starting point for precision machining at a predetermined distance inward from the larger end of the rear nozzle; measuring the diameter of the straight edge, determining the feed rate, aligning it with the predetermined distance, and precision machining the entire rear nozzle segment to achieve a complete curved surface on the internal profile of the rear nozzle. This invention effectively eliminates forward and reverse steps, satisfying the curvature requirements of the overall internal profile of the nozzle.

Description

Technical Field

[0001] This invention belongs to the field of internal curved surface processing, and particularly relates to a processing technology for the internal curved surface of a wind tunnel rotating nozzle. Background Technology

[0002] Wind tunnel rotating nozzles are used in heater nozzles in aircraft wind tunnel experimental systems to provide uniform, hypersonic airflow for aircraft during experimental research.

[0003] In existing technologies, several nozzle sections are individually machined, subjected to stress-relieving annealing, and precision machining before being assembled together. However, due to measurement errors, there are forward and reverse steps at the joints of adjacent nozzle ends, which prevents the wind tunnel from obtaining the airflow required for the experiment. Summary of the Invention

[0004] This invention provides a machining process for the inner curved surface of the nozzle of a wind tunnel rotating body, aiming to solve the above-mentioned technical problems.

[0005] This invention is implemented as follows, including:

[0006] The front nozzle and the rear nozzle are combined and positioned, wherein the diameter of the front end port of the front nozzle and the rear nozzle is larger than the diameter of the rear end port.

[0007] The nozzle is continuously precision machined from the large port to the small port of the front nozzle, and then precision machined to the large port of the rear nozzle and then machined inward a predetermined distance. At the same time, the straight edge is corrected.

[0008] Disassemble the front nozzle section and assemble and position the next nozzle section at the small port of the rear nozzle section.

[0009] Find the straight edge for calibration at a predetermined distance inward from the large end of the rear nozzle;

[0010] Measure the diameter of the corrected straight edge, determine the feed amount, connect it with the pre-machined preset distance, and finish machine the entire rear nozzle section to make the inner surface of the rear nozzle section form a complete curvature.

[0011] Furthermore, the positioning of the front nozzle and the rear nozzle assembly includes:

[0012] The front nozzle and the rear nozzle are assembled and fixed using positioning components;

[0013] The positioning assembly includes a concave-convex stop, a positioning pin, a pin hole, a connecting bolt group, and a screw hole. The front nozzle and the rear nozzle are positioned by the combination of the positioning pin and the pin hole, as well as the continuous bolt group and the screw hole.

[0014] Furthermore, the measured diameter of the corrected straight edge, determining the feed rate, includes:

[0015] The measured diameter of the corrected straight edge is compared with the theoretical value.

[0016] The feed rate is determined based on the difference between the theoretical value and the measured diameter.

[0017] Furthermore, it also includes:

[0018] After the inner surfaces of all nozzles are machined, they are assembled together and 3D scanned to determine the surface flatness of the overall inner surfaces of the nozzles.

[0019] Furthermore, the nozzle is continuously precision-machined from the large port to the small port of the front nozzle, and then precision-machined to a predetermined distance inward from the large port of the rear nozzle. Simultaneously, the straight edges are machined and corrected, including:

[0020] From the large port of the front nozzle towards the small port, precision machining is performed according to the inner surface curve data;

[0021] During the precision machining process, based on the internal profile curve data, the machining continues until the large end of the rear nozzle is 5- meters inward.

[0022] A distance of 12mm;

[0023] Continue machining the straight section for 5-12mm as a correction for the straight edge.

[0024] Furthermore, the nozzle includes an integrally formed flange, on which multiple sets of screw holes and pin holes are provided. The continuous bolt group is fixed in the multiple sets of screw holes, and the positioning pin is positioned in the pin hole.

[0025] Beneficial effects

[0026] The machining process for the inner curved surface of the nozzle of a wind tunnel rotating body disclosed in this application involves positioning and assembling the front and rear nozzle sections, then continuously precision machining the inner surface from the large end of the rear nozzle section inwards, followed by precision machining of the straight sections to obtain a corrected straight edge. The front nozzle section is disassembled, and the next nozzle section is connected. The precision machining starting point is found at the large end of the rear nozzle section. The feed rate is calculated based on the corrected straight edge, and continuous precision machining of the inner surface is performed based on the inner surface curve data until all nozzle sections are machined, thereby achieving a smooth, stepless inner surface of the entire nozzle. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of a wind tunnel rotary nozzle structure provided in an embodiment of the present invention;

[0028] Figure 2 This is a schematic diagram of the fifth nozzle 5 and the fourth nozzle 4 provided in an embodiment of the present invention;

[0029] Figure 3 This is a schematic diagram of the fourth nozzle 4 and the third nozzle 3 provided in an embodiment of the present invention;

[0030] Figure 4 This is a schematic diagram of the positioning component 6 provided in an embodiment of the present invention;

[0031] The labels in the diagram represent:

[0032] 1-First nozzle section, 2-Second nozzle section, 3-Third nozzle section, 4-Fourth nozzle section, 5-Fifth nozzle section, 6-Positioning assembly, 61-Concave-convex stop, 62-Positioning pin, 63-Continuous bolt assembly, 64-Flange, 7-Correcting straight edge. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0034] Wind tunnel rotary nozzles are mainly used in aircraft testing systems to establish ground wind tunnels and provide the specific airflow required for ground tests. Therefore, the design of wind tunnel nozzles directly affects the airflow during the test, especially the smoothness of the inner surface of the wind tunnel nozzle. If there are forward and reverse steps on the inner surface, then it is impossible to obtain uniform, hypersonic airflow.

[0035] See Figure 1 This is a schematic diagram of a wind tunnel rotating nozzle structure provided by an embodiment of the present invention. The diagram includes a first nozzle 1, a second nozzle 2, a third nozzle 3, a fourth nozzle 4, and a fifth nozzle 5. The nozzles at adjacent ends are connected and positioned by positioning components 6.

[0036] In the existing technology, when processing the inner surface of the nozzle of the wind tunnel rotating body, a process technology of processing each of the five nozzle sections separately is used. The inner surfaces of the five nozzle sections are processed separately and then assembled together. In particular, it is difficult to ensure the continuity of the inner surface curves of the five nozzle sections during the processing, which can easily cause forward and reverse steps on the inner surface.

[0037] This invention provides a machining process for the inner curved surface of a wind tunnel rotating nozzle, specifically including:

[0038] The front and rear nozzle sections are positioned together, with the diameter of the front end of each nozzle being larger than the diameter of the rear end. The front nozzle is continuously precision-machined from its larger end to its smaller end, continuing until a predetermined distance is reached from the larger end of the rear nozzle. Simultaneously, a straight edge is machined to correct the deviation. The front nozzle is disassembled, and the next nozzle section is positioned at the smaller end of the rear nozzle. A straight edge is located at a predetermined distance from the larger end of the rear nozzle, serving as the starting point for precision machining. The diameter of the straight edge is measured, the feed rate is determined, and the section is aligned with the pre-machined predetermined distance. The entire rear nozzle section is then precision-machined to ensure a complete curvature on its inner surface.

[0039] In this embodiment of the invention, during the specific processing, see... Figure 2 , Figure 2 The diagram shows the structure of the fifth nozzle 5 and the fourth nozzle 4 provided in the embodiment of the present invention.

[0040] like Figure 2 As shown in the embodiment of the present invention, during the machining of the inner curved surface of the nozzle, the fifth nozzle segment 5 and the fourth nozzle segment 4 are first positioned by the positioning component 6. The port diameter of the fifth nozzle segment 5 is larger than the front port diameter of the fourth nozzle segment 4. Therefore, at the connection between the fifth nozzle segment 5 and the fourth nozzle segment 4, a continuous inner curved surface is required. Therefore, in the machining process disclosed in this application, after the fifth nozzle segment 5 and the fourth nozzle segment 4 are positioned by combination, the port combination of the two nozzle segments is continuously precision machined into place, and the straight edge 7 is precision machined and corrected inside the large port of the fourth nozzle segment 4.

[0041] Specifically, continuous straight precision turning involves using a data lathe to continuously precision turn the inner surfaces of the two nozzle sections according to the curve data in one go, making the connection between the inner surfaces of the two nozzle sections smooth. At the same time, straight edges are turned out to correct them. This not only eliminates the forward and reverse steps that occur during individual machining, but also provides a correction benchmark for machining the next nozzle section.

[0042] Specifically, according to Figure 1 As shown, starting from the large end of the fifth nozzle segment 5 and moving towards the small end, the inner surface curve data is used for precision machining to complete the inner surface of the fifth nozzle segment 5 in one go. Then, the large end of the fourth nozzle segment 4 is precision machined inwards by 10mm according to the curve data. Afterwards, a straight section of 10mm is precision machined inwards from the large end of the fourth nozzle segment 4 as a correction straight edge 7.

[0043] Next, disassemble the fifth nozzle section 5 and assemble and position the third nozzle section 3 and the fourth nozzle section 4. Locate the straight edge 7 10mm inward from the large end of the fourth nozzle section 4, and use it as the starting point for fine machining.

[0044] Measure the diameter of the straight edge 7 inside the four large ports of the fourth nozzle section. Compare the measured diameter of the straight edge 7 with the theoretical value. Subtract the measured diameter from the theoretical value to obtain the feed rate. Therefore, starting from the finish turning starting point, continue finish turning according to the feed rate and the inner surface data, and connect with the already finish-turned 10mm distance at the four large ports of the fourth nozzle section during the finish turning process, until the inner surface of the fourth nozzle section 4 is finished. At the same time, finish turn to the preset distance of 10mm at the three large ports of the third nozzle section 3, and then turn another 10mm of the straight edge 7.

[0045] Next, disassemble the fourth nozzle section 4, and position the second nozzle section 2 and the third nozzle section 3 together. Locate the straight edge 7 at the large end of the third nozzle section 3 inside the housing as the starting point for precision machining. Calculate the measured diameter of the straight edge 7 of the third nozzle section 3. Subtract the measured diameter from the theoretical value to obtain the feed rate. Starting from the precision machining starting point, continue precision machining according to the feed rate and the inner surface data until the inner surface of the third nozzle section 3 is finished. Simultaneously, precision machine to a preset distance of 10mm at the large end of the second nozzle section 2, and then machine the straight edge 7 for another 10mm.

[0046] Finally, disassemble the third nozzle section 3, position and combine the first nozzle section 1 and the second nozzle section 2, and repeat the above processing process until the first nozzle section 1 is processed.

[0047] After the inner surfaces of all nozzles are machined, the five nozzle segments are assembled together, and the curvature of the overall inner surface of the nozzles is determined by 3D scanning. Because the inner surface of the connection between each pair of adjacent nozzle segments is continuously precision machined, there are no forward or reverse steps at the connection between the two nozzle segments, and the curvature of the overall inner surface of the assembled five nozzle segments also meets the standard.

[0048] like Figure 2 and Figure 4 As shown, the positioning component 6 includes a concave-convex stop 61, a positioning pin 62, a pin hole, and a connecting bolt group 63. A flange 64 is provided on the outer periphery of the nozzle. The flange 64 is integrally formed with the nozzle. Multiple sets of screw holes and pin holes are provided on the flange 64. The continuous bolt group 63 is respectively set in the multiple sets of screw holes for fixing. The positioning pin 62 is set in the pin hole for positioning.

[0049] The flanges 64 of two adjacent nozzle sections are respectively provided with raised face plates 61. One nozzle section flange 64 is provided with a notch, and the other nozzle section flange 64 is provided with a convex face plate. When the two nozzle sections are connected, the raised face plates 64 are closed by the raised face plates 61, which can play a sealing role.

[0050] As described above, during the machining of the nozzle inner surface, the inner surface of the rear nozzle is continuously precision machined into place by positioning and combining the front and rear nozzle sections, and then precision machined to a preset distance inward from the large end of the rear nozzle to obtain the straight edge 7. This ensures that the inner surfaces of the front and rear nozzle sections are flat without any steps, while also meeting the curvature requirements of the overall nozzle inner surface.

[0051] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A machining process for the inner curved surface of a wind tunnel rotating nozzle, characterized in that, include: The front nozzle and the rear nozzle are combined and positioned, wherein the diameter of the front end port of the front nozzle and the rear nozzle is larger than the diameter of the rear end port. The nozzle is continuously precision machined from the large port to the small port of the front nozzle, and then precision machined to the large port of the rear nozzle and then precision machined inward at a predetermined distance. The straight edge is then corrected by precision machining inward at the predetermined distance from the large port of the rear nozzle. Disassemble the front nozzle section and assemble and position the next nozzle section at the small port of the rear nozzle section. Find the straight edge for calibration at a predetermined distance inward from the large end of the rear nozzle; Measure the diameter of the corrected straight edge, determine the feed amount, connect it with the pre-machined preset distance, and finish machine the entire rear nozzle section to make the inner surface of the rear nozzle section form a complete curvature.

2. The machining process for the inner curved surface of the wind tunnel rotating body nozzle according to claim 1, characterized in that, The method of assembling and positioning the front nozzle and the rear nozzle includes: The front nozzle and the rear nozzle are assembled and fixed using positioning components; The positioning assembly includes a concave-convex stop, a positioning pin, a pin hole, a connecting bolt group, and a screw hole. The front nozzle and the rear nozzle are positioned by the combination of the positioning pin and the pin hole, as well as the continuous bolt group and the screw hole.

3. The machining process for the inner curved surface of the wind tunnel rotating body nozzle according to claim 1, characterized in that, The measured diameter of the corrected straight edge is used to determine the feed rate, including: The measured diameter of the corrected straight edge is compared with the theoretical value. The feed rate is determined based on the difference between the theoretical value and the measured diameter.

4. The machining process for the inner curved surface of the wind tunnel rotating body nozzle according to claim 1, characterized in that, Also includes: After the inner surfaces of all nozzles are machined, they are assembled together and 3D scanned to determine the surface flatness of the overall inner surfaces of the nozzles.

5. The machining process for the inner curved surface of the wind tunnel rotating body nozzle according to claim 1, characterized in that, The nozzle is continuously precision-machined from the large port to the small port of the front nozzle, and then precision-machined inwards at a predetermined distance from the large port of the rear nozzle. Finally, precision-machined inwards at the predetermined distance from the large port of the rear nozzle to correct the straight edge, including: From the large port of the front nozzle towards the small port, precision machining is performed according to the inner surface curve data; During the precision machining process, based on the inner surface curve data, continuously precision machine to a distance of 5-12mm inward from the large end of the rear nozzle; Continue machining the straight section for 5-12mm as a correction for the straight edge.

6. The machining process for the inner curved surface of the wind tunnel rotating nozzle according to claim 2, characterized in that, The nozzle includes an integrally formed flange with multiple sets of screw holes and pin holes. The continuous bolt group is fixed in the multiple sets of screw holes, and the positioning pin is positioned in the pin hole.

Images