A method for removing weight from a centrifugal compressor impeller with a circular-arc profile

Abstract

The present application relates to a kind of centrifugal compressor circular arc profile impeller's weight removal method, for solving the problem that the weight removal amount cannot be determined by now directly through manual polishing processing impeller.The present application includes the following steps: step 1, identify the impeller with circular arc profile, and place the impeller with circular arc profile on the vertical lathe workstation of machine tool;Step 2, the impeller with circular arc profile is divided into single circular arc impeller, double circular arc impeller and three circular arc impeller according to the number of circular arc;Step 3, determine the weight removal characteristic curve and weight removal characteristic body corresponding to single circular arc impeller, double circular arc impeller and three circular arc impeller respectively;Step 4, review the weight removal characteristic body obtained;If appropriate, go to step 5;If not appropriate, go to step 3;Step 5, the data of weight removal characteristic body in step 4 is input to the control center corresponding to machine tool to complete the weight removal processing of impeller.

Description

Technical Field

[0001] This invention relates to a method for machining and designing an impeller, specifically a method for reducing weight in a centrifugal compressor impeller with an arc-shaped profile. Background Technology

[0002] After the centrifugal compressor impeller is processed, it needs to undergo a low-speed balancing test. During the test, due to the machining and welding precision of the impeller, there will be an imbalance. It is necessary to remove the imbalance to meet the test requirements.

[0003] The existing methods for removing the imbalance of centrifugal compressor impellers mainly involve grinding the marked weight-removing areas on the impeller using angle grinders and straight grinders.

[0004] The different profiles of impellers make grinding difficult, making it hard to process large batches of impellers simultaneously.

[0005] For centrifugal compressor impellers with arc-shaped profiles, the method of manually grinding the de-weighted areas using angle grinders and straight grinders can lead to unreliable weight reduction, resulting in excessive weight removal or repeated de-weighting, while also producing poor surface appearance quality of the impeller. Summary of the Invention

[0006] This invention provides a method for removing weight from the arc-shaped profile impeller of a centrifugal compressor, which solves the problems of uncertain weight removal and poor surface appearance quality caused by directly grinding the impeller by hand.

[0007] To achieve the above objectives, the technical solution of the present invention is as follows:

[0008] A method for removing weight from an arc-shaped impeller of a centrifugal compressor, characterized by the following steps:

[0009] Step 1: Identify the impeller with an arc-shaped outline and place it on the vertical lathe worktable of the machine tool, making the offset between the impeller rotation center line and the de-weighting turning center line h.

[0010] Step 2: Based on the arc shape of the impeller's outer contour, simulate the corresponding de-weighting characteristic curve and de-weighting characteristic body.

[0011] Step 4: Verify whether the obtained deduplication feature body meets the requirements;

[0012] Step 5: Input the data of the de-duplication feature body that meets the requirements into the machine tool's control center. The control center controls the cutting tool to perform turning, and finally completes the de-duplication process of the impeller.

[0013] Furthermore, in step 1, the de-weighting area is marked on the impeller, and the central axis of the de-weighting area intersects with the impeller rotation center line and the de-weighting turning center line;

[0014] The de-weighting area on the impeller is placed on the side farther from the de-weighting turning center line.

[0015] Furthermore, in step 3, based on the arc shape of the impeller's outer contour, the impeller includes a single arc impeller, a double arc impeller, and a triple arc impeller.

[0016] Further, in step 3, when the impeller is a single-circular-arc impeller, the de-weighting characteristic curve and de-weighting characteristic body of the single-circular-arc impeller are simulated based on the arc shape of the impeller's outer contour, specifically as follows:

[0017] Step 3.1, determine the starting point of the deduplication characteristic curve.

[0018] The starting point of the outer circular arc curve of the original contour of the single circular arc impeller is offset by 10mm as the starting point B of the weight reduction feature circular arc curve.

[0019] Step 3.2, determine the endpoint of the deduplication characteristic curve.

[0020] The endpoint of the weight-removal characteristic curve of a single circular arc impeller is the same as the endpoint of the original profile curve of the impeller, both being A;

[0021] Step 3.3, Determine the deduplication characteristic curve

[0022] The radius Rt_in of the weight-removing characteristic curve of the single circular arc impeller is initially determined, such that Rt_in is smaller than the value of the radius Rt of the original profile curve of the impeller. Then, the weight-removing characteristic curve is initially determined by the starting point B, the ending point A, and the radius Rt_in.

[0023] Step 3.4, Simulate the deduplication feature body

[0024] In the simulation software, the z-axis is defined as the impeller rotation center line, and an axis parallel to the z-axis is defined as the de-lamination turning center line, with an offset h between the z-axis and the axis.

[0025] On the side of the axis away from the z-axis, the original profile curve of the impeller and the weight removal feature curve are drawn. The original profile curve of the impeller is rotated with the z-axis as the rotation axis to obtain the impeller model without flow channels.

[0026] Select the deduplication feature curve, rotate it around the axis as the rotation axis to obtain the deduplication feature surface;

[0027] By trimming the impeller model using the deduplication feature surface, the deduplication feature body of the impeller was obtained, and the angle of the deduplication region of the deduplication feature body is ≤90 degrees.

[0028] Step 4 specifically involves: analyzing the material properties of the impeller and the weight-removing feature body to obtain the mass of the weight-removing feature body;

[0029] If the quality of the deduplicated feature meets the weight requirement, proceed to step 5; otherwise, adjust Rt_in and return to step 3.1.

[0030] Furthermore, in step 3, the impeller is a double-arc impeller. Based on the arc shape of the double-arc impeller's outer contour, the de-weighting characteristic curve and de-weighting characteristic body of the double-arc impeller are simulated, specifically as follows:

[0031] Step 3.1, determine the starting point of the deduplication characteristic curve.

[0032] The starting point P1 of the original profile curve of the double circular arc impeller is offset by 10mm as the starting point C of the weight reduction feature curve.

[0033] Step 3.2, determine the endpoint of the deduplication characteristic curve.

[0034] The endpoint of the weight-removal characteristic curve of the double-circular arc impeller is the same as the endpoint of the original profile curve of the impeller, both being A1;

[0035] Step 3.3, Determine the deduplication characteristic curve

[0036] The intersection point B1 of the first and second arcs in the original impeller profile curve is horizontally shifted by △X to the side of the de-weighting turning center line to position B1', thereby determining the intersection point B1' of the first and second arcs in the de-weighting characteristic curve.

[0037] By selecting start point C as the starting point of the first arc segment and B1' as the ending point of the first arc segment, the radius Rt1_in of the first arc segment in the weight reduction characteristic curve is equal to the radius Rt1 of the first arc segment in the original impeller profile curve. By selecting end point A1 as the starting point of the second arc segment in the weight reduction characteristic curve and B1' as the ending point of the second arc segment in the weight reduction characteristic curve, the radius Rt2_in of the second arc segment in the weight reduction characteristic curve is equal to the radius Rt2 of the second arc segment in the original impeller profile curve. Finally, the weight reduction characteristic curve of the double-arc impeller is determined by start point C, end point A1, ΔX, and radii Rt1_in and Rt2_in.

[0038] Step 3.4, Simulate the deduplication feature body

[0039] In the simulation software, the z-axis is defined as the impeller rotation center line, and an axis parallel to the z-axis is defined as the de-lamination turning center line, with an offset h between the z-axis and the axis.

[0040] On the side of the axis away from the z-axis, the original profile curve of the impeller and the weight removal feature curve are drawn. The original profile curve of the impeller is rotated with the z-axis as the rotation axis to obtain the impeller model without flow channels.

[0041] Select the deduplication feature curve, rotate it around the axis as the rotation axis to obtain the deduplication feature surface;

[0042] By trimming the impeller model using the de-duplication feature surface, the de-duplication feature body of the impeller was obtained, and the de-duplication region angle Z of the de-duplication feature body is ≤90°;

[0043] Step 4 specifically involves: analyzing the material properties of the impeller and the weight-removing feature body to obtain the mass of the weight-removing feature body;

[0044] If the quality of the deduplicated feature meets the weight requirement, proceed to step 5; otherwise, adjust Rt_in and return to step 3.1.

[0045] Furthermore, in step 3, the impeller is a three-circular-arc impeller. Based on the arc shape of the three-circular-arc impeller's outer contour, the de-weighting characteristic curve and de-weighting characteristic body of the three-circular-arc impeller are simulated, specifically as follows:

[0046] Step 3.1, determine the starting point of the deduplication characteristic curve.

[0047] The starting point P2 of the original profile curve of the three-circular arc impeller is offset by 10mm as the starting point D of the weight reduction feature curve.

[0048] Step 3.2, determine the endpoint of the deduplication characteristic curve.

[0049] The endpoint of the weight-removing characteristic curve of the three-circular arc impeller is the same as the endpoint of the original profile curve of the impeller, both being A2;

[0050] Step 3.3, Determine the deduplication characteristic curve

[0051] The intersection point B2 of the first and second arc segments and the intersection point C1 of the second and third arc segments in the original impeller profile curve are horizontally shifted by △X1 and △X2 to the de-weighting turning center line to the positions of B2' and C1', respectively. This determines the intersection point B2' of the first and second arc segments and the intersection point C1' of the second and third arc segments in the de-weighting characteristic curve.

[0052] By selecting start point D as the starting point of the first arc in the de-weighting characteristic curve and C1' as the ending point of the first arc in the de-weighting characteristic curve, the radius Rt3_in of the first arc in the de-weighting characteristic curve is equal to the radius Rt3 of the first arc in the original impeller profile curve. By selecting C1' as the starting point of the second arc in the de-weighting characteristic curve and B2' as the ending point of the second arc in the de-weighting characteristic curve, the radius Rt4_in of the second arc in the de-weighting characteristic curve is equal to the radius Rt4 of the second arc in the original impeller profile curve. By selecting A2 as the starting point of the third arc in the de-weighting characteristic curve and B2' as the ending point of the third arc in the de-weighting characteristic curve, the radius Rt5_in of the third arc in the de-weighting characteristic curve is equal to the radius Rt5 of the original impeller profile curve. Finally, the de-weighting characteristic curve is determined by the starting point D, the ending point A2, the offsets △X1 and △X2, and the radii Rt3_in, Rt4_in, and Rt5_in.

[0053] Step 3.4, Simulate the deduplication feature body

[0054] In the simulation software, the z-axis is defined as the impeller rotation center line, and an axis parallel to the z-axis is defined as the de-lamination turning center line, with an offset h between the z-axis and the axis.

[0055] On the side of the axis away from the z-axis, the original profile curve of the impeller and the weight removal feature curve are drawn. The original profile curve of the impeller is rotated with the z-axis as the rotation axis to obtain the impeller model without flow channels.

[0056] Select the deduplication feature curve, rotate it around the axis as the rotation axis to obtain the deduplication feature surface;

[0057] By trimming the impeller model using the deduplication feature surface, the deduplication feature body of the impeller was obtained, and the angle of the deduplication region of the deduplication feature body is ≤90 degrees.

[0058] Step 4 specifically involves: analyzing the material properties of the impeller and the weight-removing feature body to obtain the mass of the weight-removing feature body;

[0059] If the quality of the deduplicated feature meets the weight requirement, proceed to step 5; otherwise, adjust Rt_in and return to step 3.1.

[0060] Furthermore, step 5 is detailed below:

[0061] The coordinates of the four sides of the de-weighting feature body, the starting point coordinates, the ending point coordinates, the radius of the de-weighting feature curve, the de-weighting depth, and the offset are measured and input into the machine tool's control center. The control center then controls the cutting tool, which starts cutting from the starting point coordinates and stops cutting at the ending point coordinates.

[0062] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0063] 1. The weight reduction method of this invention can accurately calculate the weight of the area to be reduced, ensuring that the impeller is de-weighted strictly in accordance with the weight reduction requirements. When the machine tool operator follows this method, there will be no situation where the impeller is under-weighted or over-weighted, thus avoiding affecting the quality and performance of the impeller.

[0064] 2. The present invention determines the weight removal method for different types of arcs on the arc-shaped profile impeller of a centrifugal compressor. The machine operator can use the parameters obtained by the weight removal method to perform impeller deflection and weight removal machining, which can ensure a smooth transition between the weight removal area and other areas of the impeller, improve the surface appearance quality, and obtain the depth and angle of the weight removal area of ​​the impeller in advance, providing a reference standard for subsequent machining. Attached Figure Description

[0065] Figure 1 This is a schematic diagram of the impeller mounted on the vertical lathe workbench in an embodiment of the present invention;

[0066] Figure 2 This is a schematic diagram of deduplication calculation for a single circular arc outline in an embodiment of the present invention;

[0067] Figure 3 This is a schematic diagram of deduplication calculation for a double-circular-arc shape in an embodiment of the present invention;

[0068] Figure 4 This is a schematic diagram of the deduplication calculation for a three-circular-arc outline in an embodiment of the present invention.

[0069] The accompanying figure is labeled as follows:

[0070] 1. Impeller, 2. Vertical lathe worktable, 3. De-weighting area, 4. De-weighting turning center line, 5. Impeller rotation center line. Detailed Implementation

[0071] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0072] A method for removing weight from an arc-shaped impeller of a centrifugal compressor, the specific steps of which are as follows:

[0073] 1. Identify and place impeller 1

[0074] 1.1 Identify impeller 1 with an arc-shaped outline.

[0075] 1.2 Place the impeller 1, with an arc-shaped outline, on the vertical lathe worktable 2 of the machine tool at a certain eccentric distance and align and level it so that the distance between the impeller rotation center line 5 and the de-weighting turning center line 4 is the offset h. Figure 1 As shown.

[0076] 1.3 The central axis of the turning and weight-removing area 3 marked on the impeller 1 is passed through the impeller rotation center line 5 and the weight-removing turning center line 4 to facilitate a stable and safe cutting process. The turning and weight-removing area 3 on the impeller 1 is placed on the side farther away from the weight-removing turning center line 4, and the cutting tool is clamped on the tool holder on the vertical lathe table in preparation for cutting.

[0077] 2. Simulation Calculation Method for Weight Reduction of Impellers with Different Profiles

[0078] Simulate the deduplication feature curve and deduplication feature volume in NX software.

[0079] Impeller 1 has an arc-shaped outline, and can be further divided into single arc impeller, double arc impeller and triple arc impeller according to the outline.

[0080] 2.1 For impellers with a single circular arc outline

[0081] like Figure 2 As shown, by offsetting the impeller rotation centerline 5 by h as the de-weighting turning centerline 4, cutting needs to be performed according to the de-weighting characteristic curve during cutting. Therefore, it is necessary to first determine the de-weighting characteristic curve. The process of determining the de-weighting characteristic curve is as follows:

[0082] 2.1.1 Determine the starting point of the deduplication characteristic curve.

[0083] The starting point P of the original impeller profile curve is offset by 10mm as the starting point B of the weight removal feature curve, and the 10mm offset is used as the reference surface for turning.

[0084] 2.1.2 Determine the endpoint of the deduplication characteristic curve

[0085] The endpoint A of the weight reduction characteristic curve coincides with the endpoint of the original impeller profile curve.

[0086] 2.1.3 Determining the deduplication characteristic curve

[0087] The initial value of the radius Rt_in of the de-weighting characteristic curve of a single circular arc should, in principle, be smaller than the radius Rt of the original outer arc of the impeller. By drawing the original impeller profile curve in NX software according to the design drawings, and simultaneously selecting the start and end points of the de-weighting characteristic curve determined in steps 2.1.1 and 2.1.2, the radius Rt_in of the de-weighting characteristic curve is assigned a value smaller than the original impeller arc radius Rt, thus forming the de-weighting characteristic curve.

[0088] 2.1.4 Simulating Deduplication Feature Volume

[0089] In the NX software, create an axis parallel to the z-axis on the sketch as the deweighting turning center line 4, set the offset to h, and use the z-axis as the impeller rotation center line 5. Using the rotate command, select the original impeller profile curve, and use the z-axis as the rotation axis to obtain the original impeller model without flow channels. Select the deweighting feature curve, and use an axis parallel to the z-axis as the deweighting feature rotation axis to obtain the deweighting feature surface. Use the deweighting feature surface as a tool to trim the original impeller model, thus generating the deweighting feature body of the impeller. Through material property analysis, perform a quality analysis on the deweighting feature body to obtain the weight to be removed. Compare this to the required weight to be removed. If it does not meet the requirements, adjust the above variable parameter values, including center offset h ≤ 35mm and deweighting feature curve radius Rt_in, until the quality requirements are met. Since the angle Z of the deweighting area should not be too large, the principle is that the angle Z of the deweighting area should be ≤ 90 degrees. An excessively large deweighting angle will lead to inaccurate calculation results in the simulation. This finally determines the offset h and the radius Rt_in of the deweighting feature curve.

[0090] 2.2 For double circular arc impellers

[0091] 2.2.1 Determine the starting point of the deduplication characteristic curve

[0092] like Figure 3 As shown, the starting point P1 of the original outer circle of the impeller is offset by at least 10mm as the starting point C of the weight removal feature curve, and the reserved 10mm is used as the reference surface for turning.

[0093] 2.2.2 Determine the endpoint of the deduplication characteristic curve

[0094] The endpoint of the deduplication characteristic curve coincides with the endpoint A1 of the original impeller profile curve.

[0095] 2.2.3 Determine the deduplication characteristic curve

[0096] In the NX sketch, draw the original impeller profile curve based on the impeller's outer contour line in the design drawing. In UG, use the sketch to shift the intersection point B1 of the two circular arcs in the original impeller profile curve horizontally inward by a distance △X to position B1', thus determining the intersection position of the two circular arc segments in the deduplication feature curve. To ensure the smoothness of the deduplication feature curve, the radii Rt1_in and Rt2_in of the double circular arc deduplication feature curve should be equal to the radii Rt1 and Rt2 of the double circular arcs in the original impeller profile curve, respectively. Rt1_in is the radius of the first circular arc segment in the deduplication feature curve, and Rt2_in is the radius of the second circular arc segment in the deduplication feature curve. Based on the determined start and end points of the weight reduction characteristic curve and the horizontal offset point B1', by selecting the starting point C as the starting point of the first arc and B1' as the ending point of the first arc, the radius Rt1_in of the first arc is equal to the radius Rt1 of the first arc in the original impeller profile curve, thus determining the curve of the first arc in the weight reduction characteristic curve. By selecting the ending point A1 as the starting point of the second arc and B1' as the ending point of the second arc, the radius Rt2_in of the second arc in the weight reduction characteristic curve is equal to the radius Rt2 of the second arc in the original impeller profile curve, thus determining the curve of the second arc in the weight reduction characteristic curve. Finally, the weight reduction characteristic curve is determined.

[0097] 2.2.4 Simulated Deduplication Feature Volume

[0098] In the NX sketch, create an axis parallel to the z-axis as the impeller rotation centerline 5, and the z-axis as the deweighting turning centerline 4. The offset between the z-axis and the parallel axis is h. Using the rotate command, select the original impeller profile curve and use the z-axis as the rotation axis to obtain the original impeller model without flow channels. Select the deweighting feature curve and use the axis parallel to the z-axis as the deweighting feature rotation axis to obtain the deweighting feature surface. Use the deweighting feature surface as a tool to trim the original impeller model, thus generating the deweighting feature body of the impeller. By analyzing the material properties and performing a mass analysis on the deweighting feature body of the impeller, the weight to be deweighted can be obtained. Compare this to the required weight to be deweighted. If it does not meet the requirement, adjust the above variable parameter values, including the offset h and ΔX, until the weight to be deweighted is met. In principle, the angle Z of the deweighting area should be ≤ 90 degrees. This finally determines the center offset h and the horizontal cutting depth distance for deweighting.

[0099] 2.3 For three-circular-arc impellers

[0100] 2.3.1 Determine the starting point of the deduplication characteristic curve

[0101] like Figure 4 As shown, for an impeller with a three-circle-arc outer contour, three segments of the arc are selected for weight removal. The starting point P2 of the original outer circle of the impeller is offset by at least 10mm as the starting point D of the weight removal feature curve, and the reserved 10mm is used as the reference surface for turning and dialing.

[0102] 2.3.2 Determine the endpoint of the deduplication characteristic curve

[0103] The endpoint A2 of the deduplication characteristic curve coincides with the endpoint of the original impeller profile curve.

[0104] 2.3.3 Determining the deduplication characteristic curve

[0105] In the NX sketch, draw the original impeller profile curve based on the impeller's outer contour line. In UG software, use the sketch to offset the intersection points B2 and C1 of the three arc segments in the original impeller profile curve horizontally inward by distances △X1 and △X2 to positions B2' and C1', thus determining the intersection points of the three arc segments of the weight-reduction feature curve. To ensure the smoothness of the weight-reduction feature curve, the radii Rt3_in, Rt4_in, and Rt5_in of the three arc segments of the weight-reduction feature curve of the three-arc impeller should be equal to the radii Rt3, Rt4, and Rt5 of the original impeller profile curve, respectively. Based on the determined starting and ending points of the weight-reduction feature curve, and the horizontal offset points B2' and C1', starting point D is selected as the starting point of the first arc segment in the weight-reduction feature curve, and horizontal offset point C1' is selected as the ending point of the first arc segment in the weight-reduction feature curve. The radius Rt3_in of the first arc segment of the weight-reduction feature curve is equal to the radius Rt3 of the first arc segment in the original impeller profile curve. Thus, the curve of the first arc segment in the three arc segments of the weight-reduction feature curve is determined. Horizontal offset point C2' is selected as the starting point of the second arc segment in the weight-reduction feature curve, and horizontal offset point B2' is selected as the starting point of the second arc segment in the weight-reduction feature curve. The endpoint is reached when the radius Rt4_in of the second arc in the weight-reduction feature curve is equal to the radius Rt4 of the second arc in the original impeller profile curve, thus determining the curve of the second arc in the weight-reduction feature curve. By selecting endpoint A2 as the starting point of the third arc in the weight-reduction feature curve and horizontal offset B2' as the endpoint, the radius Rt5_in of the third arc in the weight-reduction feature curve is equal to the radius Rt5 of the third arc in the original impeller profile curve, thus determining the curve of the third arc in the weight-reduction feature curve. Finally, the entire weight-reduction feature curve is determined, as detailed in the appendix. Figure 4

[0106] 2.3.4 Simulating Deduplication Feature Volume

[0107] In the NX sketch, create an axis parallel to the z-axis as the impeller rotation centerline 5, and the z-axis as the deweighting turning centerline 4. The offset between the z-axis and the parallel axis is h. Using the rotate command, select the original impeller profile curve and use the z-axis as the rotation axis to obtain the original impeller model without flow channels. Select the deweighting feature curve and use the axis parallel to the z-axis as the deweighting feature rotation axis to obtain the deweighting feature surface. Use the deweighting feature surface as a tool to trim the original impeller model, thus generating the deweighting feature body of the impeller. By defining the material properties and performing quality analysis on the above area, the weight to be deweighted can be obtained. Compare this to the required weight to be deweighted. If it does not meet the requirements, adjust the above variable parameter values, including the center offset h, ΔX1, and ΔX2, until the quality requirements are met. In principle, the angle Z of the deweighting area should be ≤ 90 degrees. This finally determines the center offset h and the horizontal cutting depth distance for deweighting.

[0108] 3. Whether the area obtained from the review is appropriate.

[0109] By analyzing the angle of the de-weighting region and the weight of the de-weighting feature obtained above, if the theoretically calculated weight of the de-weighting is less than the actual required value, the above variable parameter values, including center offset h, Rt_in, △X, △X1 or △X2, are adjusted until the de-weighting requirement is met, 10mm≤h≤35mm, while taking into account the principle that the angle of the de-weighting region Z≤90 degrees.

[0110] When the original impeller profile curve has four or more segments, the calculation method for a three-segment impeller profile curve should be used as a reference.

[0111] 4. Obtain suitable parameters

[0112] The data obtained through the verification in step 3 is used to obtain the point coordinates, deduplication depth, and deduplication offset required during the turning process by embedding the analysis formula in NX.

[0113] 5. Begin turning

[0114] The coordinates and deduplication feature radius required during the turning process are input into the corresponding control center of the machine tool. The control center then controls the cutting tool, which starts turning from the starting coordinate and stops turning at the ending coordinate.

[0115] The weight of iron chips in the machined area deviates from the ideal weight removal weight by ≤5g, the angle of the weight removal area is consistent with the calculation, the weight removal depth is consistent with the theoretically calculated weight removal depth, and the machined surface and the non-machined surface have a smooth transition. The weight removal area meets the requirements for machining weight removal.

[0116] During the cutting process, the vertical lathe table 2 drives the cutting tool to rotate and turn the impeller 1. Through this eccentric machining, the turning amount in the weight-removing area gradually decreases from the middle to both sides, and finally transitions to the non-weight-removing area, achieving a smooth transition between the weight-removing area and the non-machined area of ​​the impeller. This improves the surface quality of the impeller and meets the requirement of weight removal due to impeller imbalance.

Claims

1. A method for removing weight from an arc-shaped profile impeller of a centrifugal compressor, characterized in that, Includes the following steps: Step 1: Identify the impeller (1) with an arc-shaped outline and place it on the vertical lathe worktable (2) of the machine tool, making the offset between the impeller rotation center line (5) and the de-weighting turning center line (4) h; mark the de-weighting area on the impeller (1), and the central axis of the de-weighting area intersects the impeller rotation center line (5) and the de-weighting turning center line (4); place the de-weighting area on the impeller (1) on the side farther away from the de-weighting turning center line (4); Step 2: Based on the arc shape of the impeller (1)'s outer contour, simulate the de-duplication feature curve and de-duplication feature body corresponding to the arc shape; the arc shape of the impeller (1)'s outer contour includes a single arc impeller, a double arc impeller, and a triple arc impeller; specifically: Determine the starting point of the deduplication feature curve; determine the ending point of the deduplication feature curve; preliminarily determine the deduplication feature curve using the starting point, ending point, offset, and radius; obtain the deduplication feature body using the deduplication feature curve and the deduplication feature surface; Step 3: Verify whether the obtained deduplication feature body meets the requirements; Step 4: Input the data of the de-duplication feature body that meets the requirements into the machine tool control center. The control center controls the cutting tool to perform turning, and finally completes the de-duplication process of the impeller (1). Specifically: The coordinates of the four sides of the de-weighting feature body, the starting point coordinates, the ending point coordinates, the radius of the de-weighting feature curve, the de-weighting depth, and the offset are measured and input into the machine tool's control center. The control center then controls the cutting tool, which starts cutting from the starting point coordinates and stops cutting at the ending point coordinates.

2. The method for removing weight from an arc-shaped profile impeller of a centrifugal compressor according to claim 1, characterized in that: In step 2, when the impeller (1) is a single circular arc impeller, the de-weighting characteristic curve and de-weighting characteristic body of the single circular arc impeller are simulated according to the circular arc shape of the outer contour of the single circular arc impeller, specifically: Step 2.1, determine the starting point of the deduplication characteristic curve. The starting point of the outer circular arc curve of the original contour of the single circular arc impeller is offset by 10mm as the starting point B of the weight reduction feature circular arc curve. Step 2.2, determine the endpoint of the deduplication characteristic curve. The endpoint of the weight-removal characteristic curve of a single circular arc impeller is the same as the endpoint of the original profile curve of the impeller, both being A; Step 2.3, determine the deduplication characteristic curve The radius Rt_in of the weight-removing characteristic curve of the single circular arc impeller is initially determined, such that Rt_in is smaller than the value of the radius Rt of the original profile curve of the impeller. Then, the weight-removing characteristic curve is initially determined by the starting point B, the ending point A, and the radius Rt_in. Step 2.4, Simulate the deduplication feature body In the simulation software, the z-axis is defined as the impeller rotation center line (5), and an axis parallel to the z-axis is defined as the de-weighting turning center line (4). An offset h is set between the z-axis and the axis. On the side of the axis away from the z-axis, the original profile curve of the impeller and the weight removal feature curve are drawn. The original profile curve of the impeller is rotated with the z-axis as the rotation axis to obtain the impeller model without flow channels. Select the deduplication feature curve, rotate it around the axis as the rotation axis to obtain the deduplication feature surface; By trimming the impeller model using the deduplication feature surface, the deduplication feature body of the impeller was obtained, and the angle of the deduplication region of the deduplication feature body is ≤90 degrees. Step 3 specifically involves: analyzing the material properties of the impeller and the weight-removing feature body to obtain the mass of the weight-removing feature body; If the quality of the deduplicated feature meets the weight requirement, proceed to step 4; otherwise, adjust Rt_in and return to step 2.

1.

3. The method for removing weight from an arc-shaped profile impeller of a centrifugal compressor according to claim 1, characterized in that, In step 2, the impeller (1) is a double-arc impeller. Based on the arc shape of the outer contour of the double-arc impeller, the weight reduction characteristic curve and weight reduction characteristic body of the double-arc impeller are simulated, specifically as follows: Step 2.1, determine the starting point of the deduplication characteristic curve. The starting point P1 of the original profile curve of the double circular arc impeller is offset by 10mm as the starting point C of the weight reduction feature curve. Step 2.2, determine the endpoint of the deduplication characteristic curve. The endpoint of the weight-removal characteristic curve of the double-circular arc impeller is the same as the endpoint of the original profile curve of the impeller, both being A1; Step 2.3, determine the deduplication characteristic curve The intersection point B1 of the first and second arcs in the original profile curve of the impeller is horizontally shifted by △X to the B1' position on the side of the de-weighting turning center line (4), thereby determining the intersection point B1' of the first and second arcs in the de-weighting characteristic curve. By selecting start point C as the starting point of the first arc segment and B1' as the ending point of the first arc segment, the radius Rt1_in of the first arc segment in the weight reduction characteristic curve is equal to the radius Rt1 of the first arc segment in the original impeller profile curve. By selecting end point A1 as the starting point of the second arc segment in the weight reduction characteristic curve and B1' as the ending point of the second arc segment in the weight reduction characteristic curve, the radius Rt2_in of the second arc segment in the weight reduction characteristic curve is equal to the radius Rt2 of the second arc segment in the original impeller profile curve. Finally, the weight reduction characteristic curve of the double-arc impeller is determined by start point C, end point A1, ΔX, and radii Rt1_in and Rt2_in. Step 2.4, Simulate the deduplication feature body In the simulation software, the z-axis is defined as the impeller rotation center line (5), and an axis parallel to the z-axis is defined as the de-weighting turning center line (4). An offset h is set between the z-axis and the axis. On the side of the axis away from the z-axis, the original profile curve of the impeller and the weight removal feature curve are drawn. The original profile curve of the impeller is rotated with the z-axis as the rotation axis to obtain the impeller model without flow channels. Select the deduplication feature curve, rotate it around the axis as the rotation axis to obtain the deduplication feature surface; By trimming the impeller model using the de-duplication feature surface, the de-duplication feature body of the impeller was obtained, and the de-duplication region angle Z of the de-duplication feature body is ≤90°; Step 3 specifically involves: analyzing the material properties of the impeller and the weight-removing feature body to obtain the mass of the weight-removing feature body; If the quality of the deduplicated feature meets the weight requirement, proceed to step 4; otherwise, adjust Rt_in and return to step 2.

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4. The method for removing weight from an arc-shaped profile impeller of a centrifugal compressor according to claim 1, characterized in that: In step 2, the impeller (1) is a three-circular-arc impeller. Based on the arc shape of the three-circular-arc impeller's outer contour, the weight reduction characteristic curve and weight reduction characteristic body of the three-circular-arc impeller are simulated, specifically as follows: Step 2.1, determine the starting point of the deduplication characteristic curve. The starting point P2 of the original profile curve of the three-circular arc impeller is offset by 10mm as the starting point D of the weight reduction feature curve. Step 2.2, determine the endpoint of the deduplication characteristic curve. The endpoint of the weight-removing characteristic curve of the three-circular arc impeller is the same as the endpoint of the original profile curve of the impeller, both being A2; Step 2.3, determine the deduplication characteristic curve The intersection point B2 of the first and second arcs in the original profile curve of the impeller and the intersection point C1 of the second and third arcs are horizontally shifted to the side of the de-weighting turning center line (4) by △X1 and △X2 to the positions of B2' and C1' respectively, thereby determining the intersection point B2' of the first and second arcs in the de-weighting characteristic curve and the intersection point C1' of the second and third arcs; By selecting start point D as the starting point of the first arc in the de-weighting characteristic curve and C1' as the ending point of the first arc in the de-weighting characteristic curve, the radius Rt3_in of the first arc in the de-weighting characteristic curve is equal to the radius Rt3 of the first arc in the original impeller profile curve. By selecting C1' as the starting point of the second arc in the de-weighting characteristic curve and B2' as the ending point of the second arc in the de-weighting characteristic curve, the radius Rt4_in of the second arc in the de-weighting characteristic curve is equal to the radius Rt4 of the second arc in the original impeller profile curve. By selecting A2 as the starting point of the third arc in the de-weighting characteristic curve and B2' as the ending point of the third arc in the de-weighting characteristic curve, the radius Rt5_in of the third arc in the de-weighting characteristic curve is equal to the radius Rt5 of the original impeller profile curve. Finally, the de-weighting characteristic curve is determined by the starting point D, the ending point A2, the offsets △X1 and △X2, and the radii Rt3_in, Rt4_in, and Rt5_in. Step 2.4, Simulate the deduplication feature body In the simulation software, the z-axis is defined as the impeller rotation center line (5), and an axis parallel to the z-axis is defined as the de-weighting turning center line (4). An offset h is set between the z-axis and the axis. On the side of the axis away from the z-axis, the original profile curve of the impeller and the weight removal feature curve are drawn. The original profile curve of the impeller is rotated with the z-axis as the rotation axis to obtain the impeller model without flow channels. Select the deduplication feature curve, rotate it around the axis as the rotation axis to obtain the deduplication feature surface; By trimming the impeller model using the deduplication feature surface, the deduplication feature body of the impeller was obtained, and the angle of the deduplication region of the deduplication feature body is ≤90 degrees. Step 3 specifically involves: analyzing the material properties of the impeller and the weight-removing feature body to obtain the mass of the weight-removing feature body; If the quality of the deduplicated feature meets the weight requirement, proceed to step 4; otherwise, adjust Rt_in and return to step 2.1.

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