A hydraulic turbine runner and a method of manufacturing the same

Abstract

The application discloses a water turbine runner manufacturing method and relates to the field of water turbines.The runner comprises coaxially arranged inner ring segments, middle ring segments and outer ring segments; the inner ring segments are formed by welding upper crown inner blade discs and lower ring inner blade discs, both of which are integrally cast into blades, and the blades are formed into complete inner blades after butt joint; the middle ring segments and the outer ring segments are integrally cast into shapes.Adjacent segments are butt jointed to form connecting parts and corresponding welds, and the welds are located on the low stress area cylindrical surface coaxial with the runner; the manufacturing method adopts segmented casting, precise positioning assembly, step-by-step welding and stress relief annealing, and a robot is used for welding outside the circumferential welds, and a robot is used for welding the long rod welding gun after the blade welds are horizontally placed.The application can improve the welding process performance of the runner in a narrow space, avoid the size exceeding the size range of the machining equipment and the size range of the casting quality control, and improve the casting quality stability and reliability.

Description

Technical Field

[0001] This invention relates to the field of water turbines, and more specifically to a method for manufacturing a water turbine runner. Background Technology

[0002] Large runners are generally made of cast-welded upper crown, lower ring and blades; runners in narrow spaces are generally made of upper crown bladed disk, lower ring bladed disk and inner and outer ring bladed disk; however, due to the limitations of welding equipment size, grinding equipment size and poor welding process, the welding and manufacturing of runners is very difficult. The main disadvantages of runners with cast-welded upper crown, lower ring and blades are: (1) The runner adopts a cast-welded upper crown, lower ring and blades structure, the amount of welding and grinding of the runner is large, especially for runners with narrow flow channels and narrow space, it is even impossible to weld; (2) For runners in narrow spaces, the traditional structure is used, the line of sight at the root of the weld is poor, and the welding quality cannot be guaranteed; (3) The weld is located in the high stress area of ​​the runner operation, which brings greater operational risks; (4) Using upper crown or lower ring for ring division cannot effectively reduce the amount of welding, the welding manufacturing process is complicated, the manufacturing cycle is long, and it cannot quickly meet the owner's needs. The main disadvantages of the full-disc structure runner are: (1) The upper crown disc, lower ring disc or inner and outer disc structure is limited by the size of the welding equipment and the size of the grinding equipment, making the processing and manufacturing relatively inconvenient.

[0003] Chinese patent document CN116652535A, published on August 29, 2023, discloses a method for manufacturing segmented blades of a low-specific-speed mixed-flow turbine runner. It indirectly discloses a method for manufacturing a turbine runner, in which the runner is cast and machined into four parts: an upper crown blade disk, a lower inner ring blade disk, a lower outer ring blade disk, and short blades. The long blades are divided into upper and lower segments by a rotating cutting surface along the fitted centerline of the upper crown and lower ring flow channels. The short blades are the remaining portion of the blade after removing the transition steps at the root of the upper crown blade disk side, the lower inner ring blade disk side, and the lower outer ring blade disk side. This invention improves the accessibility of the runner for welding, grinding, and non-destructive testing.

[0004] However, the aforementioned technical solutions suffer from significant tortuosity and axial height in the inlet to middle section of the long blade flow channel. Regardless of whether integral casting or separate CNC machining is used, the machining space for the complex tortuous blade profile in the inner cavity is limited, and the tool accessibility of the tortuous blade profile in the inner cavity is poor. During subsequent welding and assembly, some welds are located in the narrow flow channel area, which restricts the posture of the welding torch or welding robot, making it difficult to carry out high-quality welding and thus making it difficult to guarantee the welding quality. At the same time, the welds in the connection area between the blade and the upper crown and lower ring are close to the blade root and the high-stress area of ​​the blade, which makes the runner have a greater risk of fatigue damage under alternating hydraulic loads. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention proposes a method for manufacturing a turbine runner. By dividing the runner radially into an inner ring section, a middle ring section, and an outer ring section, and then casting the blades in the middle and outer ring sections integrally with their corresponding ring bodies, this method improves the welding processability of the runner in confined spaces, reduces the number of welds in the blade area, lowers the impact of welding residual stress and welding defects on runner performance, and avoids dimensions exceeding the range of processing equipment and casting quality control dimensions. This enhances welding accessibility and welding quality stability while simultaneously improving casting quality stability and reliability.

[0006] This invention is achieved using the following technical solution: The first aspect of this invention provides a turbine runner, comprising an inner ring section, a middle ring section, and an outer ring section. The inner ring section includes an upper crown inner bladed disk and a lower ring inner bladed disk welded together. The upper crown inner bladed disk includes an upper crown inner ring and upper crown inner blades, which are integrally cast. The lower ring inner bladed disk includes a lower ring inner ring and lower ring inner blades, which are integrally cast. The upper crown inner blades and lower ring inner blades are correspondingly connected and welded together. The inner blades are fixed and welded together to form several complete inner blades. The middle ring section of the rotor includes an upper crown middle ring, a lower ring middle ring, and several middle blades evenly distributed circumferentially between the upper crown middle ring and the lower ring middle ring. The upper crown middle ring, the lower ring middle ring, and the middle blades are integrally cast into one piece. The outer ring section of the rotor includes an upper crown outer ring, a lower ring outer ring, and several outer blades evenly distributed circumferentially between the upper crown outer ring and the lower ring outer ring. The upper crown outer ring, the lower ring outer ring, and the outer blades are integrally cast into one piece. The outer circumferential surface of the inner ring section of the rotor is connected to the inner circumferential surface of the middle ring section of the rotor to form a first connecting part, and is welded to form a first connecting part weld; the outer circumferential surface of the middle ring section of the rotor is connected to the inner circumferential surface of the outer ring section of the rotor to form a second connecting part, and is welded to form a second connecting part weld. The first connecting weld includes the first annular weld of the upper crown connection, the first annular weld of the lower ring connection, and the first blade connection weld; the second connecting weld includes the second annular weld of the upper crown connection, the second annular weld of the lower ring connection, and the second blade connection weld. The weld of the first connecting part is located entirely on the same axis as the rotating wheel, and the weld of the second connecting part is located entirely on the second cylindrical surface coaxial with the rotating wheel. The diameter of the first cylindrical surface is smaller than the diameter of the second cylindrical surface.

[0007] The first cylindrical surface is located at 45% to 55% of the radial length of the blade, and the second cylindrical surface is located at 70% to 80% of the radial length of the blade, taking into account the optimal manufacturing process of casting, machining and welding.

[0008] The welding grooves between the upper inner blade disk and the lower inner blade disk, between the middle blade and the outer blade, and between the middle blade and the inner blade are X-shaped grooves. The circumferential welds between the inner ring section and the middle ring section of the runner, and between the middle ring section and the outer ring section of the runner are outer U-shaped grooves.

[0009] The first connecting annular weld of the upper crown is a butt weld between the outer circumferential surface of the inner ring of the upper crown and the inner circumferential surface of the middle ring of the upper crown; the first connecting annular weld of the lower ring is a butt weld between the outer circumferential surface of the inner ring of the lower ring and the inner circumferential surface of the middle ring of the lower ring; the first connecting weld of the blades is a butt weld between the outer edge of the inner blade and the inner edge of the middle blade; the second connecting annular weld of the upper crown is a butt weld between the outer circumferential surface of the middle ring of the upper crown and the inner circumferential surface of the outer ring of the upper crown; the second connecting annular weld of the lower ring is a butt weld between the outer circumferential surface of the middle ring of the lower ring and the inner circumferential surface of the outer ring of the lower ring; the second connecting weld of the blades is a butt weld between the outer edge of the middle blade and the inner edge of the outer blade.

[0010] The inner blade, middle blade, and outer blade correspond one-to-one, and the inner blade, middle blade, and outer blade transition smoothly at the joint. After being welded together in sequence, they form a complete rotor blade.

[0011] The number of inner blades, middle blades, and outer blades are all 9-30 pieces.

[0012] The thickness of the inner blade, middle blade, and outer blade is 10mm-150mm.

[0013] The inner cavity height of the rotor is 50mm-250mm.

[0014] The wrap angle of the complete blade is 30°-180°.

[0015] The diameter of the entire upper crown, after connecting the inner ring, middle ring, and outer ring, is 500mm-5000mm; the diameter of the entire lower ring, after connecting the inner ring, middle ring, and outer ring, is 500mm-5000mm.

[0016] A second aspect of the present invention provides a method for manufacturing a water turbine runner, comprising the following steps: S1. The rotor to be manufactured is coaxially divided into an inner ring section, a middle ring section, and an outer ring section along the radial direction of the rotor. S2. The middle ring section of the rotor is integrally cast to obtain a rotor middle ring section with an integrally formed upper crown middle ring, middle blade and lower ring middle ring; S3. The outer ring section of the rotor is integrally cast to obtain an outer ring section of the rotor with an integrally formed upper crown outer ring, outer blade and lower ring outer ring; S4. The inner ring section of the rotor is separately cast to form the upper crown inner blade disk blank and the lower ring inner blade disk blank, and after being independently precision machined, the two are positioned, assembled and welded, and then stress-relief annealing is performed to obtain the inner ring section of the rotor. S5. Using the design axis of the wheel as a reference, the inner ring section, the middle ring section and the outer ring section of the wheel are coaxially assembled in the radial direction from the inside to the outside. The outer circumferential surface of the inner ring section is connected to the inner circumferential surface of the middle ring section to form the first connecting part, and the outer circumferential surface of the middle ring section is connected to the inner circumferential surface of the outer ring section to form the second connecting part. S6. The first connecting part and the second connecting part are welded in sequence to form the weld of the first connecting part. After forming the weld of the first connecting part, a second stress-relief annealing treatment is performed. After forming the weld of the second connecting part, a third stress-relief annealing treatment is performed to weld the inner ring section, the middle ring section and the outer ring section of the runner into one piece to obtain the turbine runner.

[0017] In S4, during positioning and assembly, the inner blade disk of the upper crown and the inner blade disk of the lower ring are positioned by axial pin sleeves. Three sets of axial pin sleeves are provided and evenly distributed along the circumference of the wheel at 120°.

[0018] In S5, during coaxial assembly, the inner ring section, middle ring section, and outer ring section of the wheel are positioned by radial positioning pins. Three sets of radial positioning pins are provided and evenly distributed along the circumference of the wheel at 120°.

[0019] In S6, the first connecting weld includes an upper crown connecting annular weld one, a lower ring connecting annular weld one, and a blade connecting weld one, and the second connecting weld includes an upper crown connecting annular weld two, a lower ring connecting annular weld two, and a blade connecting weld two.

[0020] When welding the first and second annular welds of the upper crown and lower ring, a robot is used to perform argon arc welding on the outside of the wheel space, with single-sided welding and double-sided forming. Then, a robot is used for gas-shielded welding. For the first and second blade connection welds, the wheel is rotated 90° to a horizontal position, and a robot is used to perform argon arc welding on the bottom layer, with single-sided welding and double-sided forming. Then, a robot is used for gas-shielded welding.

[0021] The specially designed long-rod welding torch is 450mm-550mm long and 25mm-35mm in diameter.

[0022] Compared with the prior art, the advantages of the present invention are as follows: 1. Compared with existing technologies represented by CN116652535A, this invention employs a completely different segmented manufacturing method for the rotor. The rotor is radially divided into coaxial inner, middle, and outer ring segments. The welds are primarily concentrated on two cylindrical surfaces coaxial with the rotor and precisely positioned in the low-stress zone of the blade profile, avoiding the maximum stress section of the blade. This fundamentally reduces the risk of weld fatigue cracking. Furthermore, the inner, middle, and outer ring segments can be produced in parallel, resulting in higher production efficiency, effectively shortening the casting and machining cycle, and reducing the difficulty of machining and casting. This invention addresses the risks associated with casting turbine runners that exceed the dimensions of the machining equipment and the casting quality control dimensions, ensuring the machining range, precision, and efficiency of the inner, middle, and outer ring sections of the runner, and improving the stability and reliability of casting quality. Existing technologies, such as CN116652535A, have numerous weld seams along the flow channel, resulting in high welding difficulty and low efficiency. This invention addresses the welding challenges of turbine or pump-turbine runners in confined spaces by structurally modifying the weld seam position, changing the weld seams along the flow channel to weld seams perpendicular to the flow channel, thus improving the welding processability and grinding processability in confined spaces.

[0023] 2. This invention addresses the pain points of large blade twist, high axial height, and poor accessibility of internal cavity machining tools in the inner ring section of the impeller. It separates the inner ring section into an upper crown inner bladed disk with semi-airfoil blades and a lower ring inner bladed disk, which are cast separately. The blade surfaces of the two bladed disks can be precision machined separately, solving the problem that the twisted blades in the inner cavity of the whole inner ring section cannot be fully machined, and the machining cost increases by more than 3 times. The inner blades, middle blades, and outer blades are welded together to form a complete and continuous blade. The flow surface is smooth without misalignment or steps, which greatly reduces water flow eddies and hydraulic losses.

[0024] 3. In this invention, X-shaped groove welding is used between the inner blade of the upper crown and the inner blade of the lower ring, between the middle blade and the outer blade, and between the middle blade and the inner blade. This results in more complete fusion and higher welding strength, which can significantly improve the overall structural rigidity and torsional resistance of the inner ring section of the impeller and prevent weld cracking in the inner ring section under high speed and high head conditions. The circumferential weld adopts an outer U-shaped groove, with a small root gap and stable forming quality. This makes it easy for the robot to perform single-sided welding and double-sided forming on the outer side without entering the inner cavity of the impeller for welding, thus solving the problem of welding in confined spaces. Furthermore, the outer bevel design provides a spacious and accessible welding operation area, facilitating observation of the molten pool and control of the weld bead, significantly improving welding quality and flaw detection pass rate. These features, along with the segmented structure of the inner, middle, and outer ring sections of the runner, ensure the connection strength of the blades and ring sections while transferring the main welding operations to areas easily accessible to the welding equipment. This balances the overall structural load-bearing capacity, welding accessibility, and welding quality stability of the runner, avoiding the difficulty of simultaneously meeting the strength requirements of different connection parts and the welding requirements in confined spaces when using only one bevel design.

[0025] 4. In this invention, the upper and lower inner blade disks are positioned using three sets of axial pins evenly distributed along the circumference at 120°, and adjacent segments are positioned using three sets of radial positioning pins evenly distributed along the circumference at 120°. This three-point datum positioning method can ensure the coaxiality tolerance of each segment assembly, while precisely controlling the circumferential alignment accuracy of the blades, avoiding blade misalignment during assembly, and ensuring the smooth continuity of the blades after welding from the assembly stage. The positioning structure is simple to operate and can greatly improve assembly efficiency.

[0026] 5. In this invention, the inner ring section is first welded, then subjected to a first stress-relief annealing, then the middle ring section is welded and subjected to a second stress-relief annealing, and finally the outer ring section is welded and subjected to a third stress-relief annealing. This step-by-step process can completely release the welding stress generated by each welding process, avoiding the problem of stress superposition caused by concentrated welding of multiple welds, and ensuring the overall dimensional stability of the wheel. At the same time, step-by-step welding can correct the deformation of single-step welding in real time, avoiding the accumulation of errors that would lead to product scrap.

[0027] 6. In this invention, the circumferential welds are welded by a robot on the outside of the runner, and the blade welds are welded by a robot with the runner placed horizontally and a specially designed long-rod welding torch. This robotic welding scheme perfectly adapts to the narrow welding space between blades, solving the problems of insufficient depth and large fluctuations in welding quality caused by manual welding. The welding process, which uses argon arc welding for the root pass, single-sided welding for double-sided forming, and gas shielded welding for filling and covering the surface, eliminates the need to enter the inner cavity of the runner. This ensures the forming quality of the back of the weld and avoids welding defects such as incomplete penetration and slag inclusion. At the same time, robotic welding can ensure the consistency and stability of weld quality, meeting the fatigue life requirements of long-term full-load operation of hydropower stations. Attached Figure Description

[0028] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments, wherein: Figure 1 This is a schematic diagram of the cross-sectional structure of the impeller of the present invention; Figure 2 This is a schematic diagram of the first and second cylindrical surfaces of the present invention; Figure 3 This is a top view of the rotating wheel of the present invention; Figure 4 This is a cross-sectional view of section AA. Figure 5 for Figure 1 Enlarged view of area I; Figure 6 for Figure 1 Enlarged view of the middle Q area; Figure 7 This is a three-dimensional schematic diagram of the rotating wheel of the present invention; Marked in the image: 1. Inner ring section of the rotor; 2. Middle ring section of the rotor; 3. Outer ring section of the rotor; 4. Inner ring of the upper crown; 5. Inner ring of the lower ring; 6. Inner blade of the upper crown; 7. Inner blade of the lower ring; 8. Inner blade weld; 9. Middle ring of the upper crown; 10. Middle ring of the lower ring; 11. Middle blade; 12. Outer ring of the upper crown; 13. Outer ring of the lower ring; 14. Outer blade; 15. First circumferential weld of the upper crown connection; 16. First circumferential weld of the lower ring connection; 17. First blade weld; 18. Second circumferential weld of the upper crown connection; 19. Second circumferential weld of the lower ring connection; 20. Second blade weld; 21. First cylindrical surface; 22. Second cylindrical surface; 23. X-shaped bevel; 24. Outer U-shaped bevel. Detailed Implementation

[0029] Example 1 As a preferred embodiment of the present invention, refer to Figures 1-3 This embodiment provides a turbine runner, including an inner ring section 1, a middle ring section 2, and an outer ring section 3. The inner ring section 1 includes an upper crown inner blade disk and a lower ring inner blade disk welded together, all three being coaxially arranged. The upper crown inner blade disk includes an integrally cast upper crown inner ring 4 and an upper crown inner blade 6. The lower ring inner blade disk includes an integrally cast lower ring inner ring 5 and a lower ring inner blade 7. The upper crown inner blade 6 and the lower ring inner blade 7 are connected and welded together one-to-one to form an inner blade weld seam 8, forming 9 complete inner blades. (Refer to...) Figure 4 The welding bevels between the inner blade disc of the upper crown and the inner blade disc of the lower ring, between the middle blade and the outer blade, and between the middle blade and the inner blade are X-type bevels 23; The wheel middle ring section 2 includes an integrally cast upper crown middle ring 9, a lower ring middle ring 10, and 9 middle blades 11 located between the upper crown middle ring 9 and the lower ring middle ring 10 and evenly distributed along the circumference. The middle blades 11 are in a straight line with an axial height of 50mm. The outer ring section 3 of the rotor includes an integrally cast upper crown outer ring 12, a lower outer ring 13, and nine outer blades 14 located between the upper crown outer ring 12 and the lower outer ring 13 and evenly distributed along the circumference. The outer blades 14 are in a straight line and have an axial height of 50 mm. The outer circumferential surface of the inner ring section 1 of the rotor is connected to the inner circumferential surface of the middle ring section 2 of the rotor to form a first connecting part, and is welded to form a first connecting part weld; the outer circumferential surface of the middle ring section 2 of the rotor is connected to the inner circumferential surface of the outer ring section 3 of the rotor to form a second connecting part, and is welded to form a second connecting part weld; both the first connecting part weld and the second connecting part weld are outer U-shaped bevels 24, as shown in the reference. Figure 5 A schematic diagram of the U-shaped bevel on the outer side of the circumferential weld of the lower ring; refer to... Figure 6 A schematic diagram of the U-shaped bevel on the outer side of the circumferential weld of the upper crown; The first connecting weld includes an upper crown connecting annular weld 15, a lower ring connecting annular weld 16, and a blade connecting weld 17. The second connecting weld includes an upper crown connecting annular weld 18, a lower ring connecting annular weld 19, and a blade connecting weld 20. The upper crown connecting annular weld 15 is a butt weld between the outer circumferential surface of the upper crown inner ring 4 and the inner circumferential surface of the upper crown middle ring 9. The lower ring connecting annular weld 16 is a butt weld between the outer circumferential surface of the lower ring inner ring 5 and the lower ring middle ring 17. The butt welds on the inner circumferential surfaces are as follows: the blade connection weld 17 is the butt weld between the outer edge of the inner blade and the inner edge of the middle blade 11; the upper crown connection annular weld 18 is the butt weld between the outer circumferential surface of the upper crown middle ring 9 and the inner circumferential surface of the upper crown outer ring 12; the lower ring connection annular weld 19 is the butt weld between the outer circumferential surface of the lower ring middle ring 10 and the inner circumferential surface of the lower ring outer ring 13; and the blade connection weld 20 is the butt weld between the outer edge of the middle blade 11 and the inner edge of the outer blade 14. The weld of the first connecting part is entirely located on the first cylindrical surface 21, which is coaxial with the rotor, and the weld of the second connecting part is entirely located on the second cylindrical surface 22, which is coaxial with the rotor. The diameter of the first cylindrical surface 21 is smaller than the diameter of the second cylindrical surface 22, and both the first cylindrical surface 21 and the second cylindrical surface 22 are located in the low stress zone of the rotor blade profile. The first cylindrical surface 21 is located at 45% of the radial length of the blade, and the second cylindrical surface 22 is located at 70% of the radial length of the blade.

[0030] The inner blade, middle blade 11, and outer blade 14 correspond one-to-one. The thickness of the inner blade, middle blade 11, and outer blade 14 is 10mm. The complete blade wrap angle is 30°. The inner blade, middle blade 11, and outer blade 14 smoothly transition at the joint. After being welded together in sequence, they form 9 complete rotor blades. The diameter of the overall upper crown after connecting the inner ring 4, middle ring 9, and outer ring 12 is 500mm. The diameter of the overall lower ring after connecting the inner ring 5, middle ring 10, and outer ring 13 is 500mm.

[0031] Example 2 As another preferred embodiment of the present invention, refer to Figures 1-3 This embodiment provides a turbine runner, including an inner ring section 1, a middle ring section 2, and an outer ring section 3. The inner ring section 1 includes an upper crown inner blade disk and a lower ring inner blade disk welded together, all three being coaxially arranged. The upper crown inner blade disk includes an integrally cast upper crown inner ring 4 and an upper crown inner blade 6. The lower ring inner blade disk includes an integrally cast lower ring inner ring 5 and a lower ring inner blade 7. The upper crown inner blade 6 and the lower ring inner blade 7 are connected and welded together one-to-one to form an inner blade weld seam 8, forming 20 complete inner blades. (Refer to...) Figure 4 The welding bevels between the inner blade disc of the upper crown and the inner blade disc of the lower ring, between the middle blade and the outer blade, and between the middle blade and the inner blade are X-type bevels 23; The wheel middle ring section 2 includes an integrally cast upper crown middle ring 9, a lower ring middle ring 10, and 20 middle blades 11 located between the upper crown middle ring 9 and the lower ring middle ring 10 and evenly distributed along the circumference. The middle blades 11 are in a straight line with an axial height of 150mm. The outer ring section 3 of the rotor includes an integrally cast upper crown outer ring 12, a lower outer ring 13, and 20 outer blades 14 located between the upper crown outer ring 12 and the lower outer ring 13 and evenly distributed along the circumference. The outer blades 14 are in a straight line and have an axial height of 150mm. The outer circumferential surface of the inner ring section 1 of the rotor is connected to the inner circumferential surface of the middle ring section 2 of the rotor to form a first connecting part, and is welded to form a first connecting part weld; the outer circumferential surface of the middle ring section 2 of the rotor is connected to the inner circumferential surface of the outer ring section 3 of the rotor to form a second connecting part, and is welded to form a second connecting part weld; both the first connecting part weld and the second connecting part weld are outer U-shaped bevels 24; refer to Figure 5 A schematic diagram of the U-shaped bevel on the outer side of the circumferential weld of the lower ring; refer to... Figure 6 A schematic diagram of the U-shaped bevel on the outer side of the circumferential weld of the upper crown; The first connecting weld includes an upper crown connecting annular weld 15, a lower ring connecting annular weld 16, and a blade connecting weld 17. The second connecting weld includes an upper crown connecting annular weld 18, a lower ring connecting annular weld 19, and a blade connecting weld 20. The upper crown connecting annular weld 15 is a butt weld between the outer circumferential surface of the upper crown inner ring 4 and the inner circumferential surface of the upper crown middle ring 9. The lower ring connecting annular weld 16 is a butt weld between the outer circumferential surface of the lower ring inner ring 5 and the lower ring middle ring 17. The butt welds on the inner circumferential surfaces are as follows: the blade connection weld 17 is the butt weld between the outer edge of the inner blade and the inner edge of the middle blade 11; the upper crown connection annular weld 18 is the butt weld between the outer circumferential surface of the upper crown middle ring 9 and the inner circumferential surface of the upper crown outer ring 12; the lower ring connection annular weld 19 is the butt weld between the outer circumferential surface of the lower ring middle ring 10 and the inner circumferential surface of the lower ring outer ring 13; and the blade connection weld 20 is the butt weld between the outer edge of the middle blade 11 and the inner edge of the outer blade 14. The weld of the first connecting part is entirely located on the first cylindrical surface 21, which is coaxial with the rotor, and the weld of the second connecting part is entirely located on the second cylindrical surface 22, which is coaxial with the rotor. The diameter of the first cylindrical surface 21 is smaller than the diameter of the second cylindrical surface 22, and both the first cylindrical surface 21 and the second cylindrical surface 22 are located in the low stress zone of the rotor blade profile. The first cylindrical surface 21 is located at 55% of the radial length of the blade, and the second cylindrical surface 22 is located at 80% of the radial length of the blade.

[0032] The inner blade, middle blade 11, and outer blade 14 correspond one-to-one. The thickness of the inner blade, middle blade 11, and outer blade 14 is 80mm. The complete blade wrap angle is 80°. The inner blade, middle blade 11, and outer blade 14 smoothly transition at the joint. After being welded together in sequence, they form 20 complete rotor blades. The diameter of the overall upper crown after connecting the inner ring 4, middle ring 9, and outer ring 12 is 3000mm. The diameter of the overall lower ring after connecting the inner ring 5, middle ring 10, and outer ring 13 is 3000mm.

[0033] Example 3 As another preferred embodiment of the present invention, refer to Figures 1-3 This embodiment provides a turbine runner, including an inner ring section 1, a middle ring section 2, and an outer ring section 3. The inner ring section 1 includes an upper crown inner bladed disk and a lower ring inner bladed disk welded together, all three being coaxially arranged. The upper crown inner bladed disk includes an integrally cast upper crown inner ring 4 and an upper crown inner blade 6. The lower ring inner bladed disk includes an integrally cast lower ring inner ring 5 and a lower ring inner blade 7. The upper crown inner blade 6 and the lower ring inner blade 7 are connected and welded together one-to-one to form an inner blade weld seam 8, forming 30 complete inner blades. (Refer to...) Figure 4 The welding bevels between the inner blade disc of the upper crown and the inner blade disc of the lower ring, between the middle blade and the outer blade, and between the middle blade and the inner blade are X-type bevels 23; The wheel middle ring section 2 includes an integrally cast upper crown middle ring 9, a lower ring middle ring 10, and 30 middle blades 11 located between the upper crown middle ring 9 and the lower ring middle ring 10 and evenly distributed along the circumference. The middle blades 11 are in a straight line with an axial height of 250mm. The outer ring section 3 of the rotor includes an integrally cast upper crown outer ring 12, a lower outer ring 13, and 30 outer blades 14 located between the upper crown outer ring 12 and the lower outer ring 13 and evenly distributed along the circumference. The outer blades 14 are in a straight line and have an axial height of 250mm. The outer circumferential surface of the inner ring section 1 of the rotor is connected to the inner circumferential surface of the middle ring section 2 of the rotor to form a first connecting part, and is welded to form a first connecting part weld; the outer circumferential surface of the middle ring section 2 of the rotor is connected to the inner circumferential surface of the outer ring section 3 of the rotor to form a second connecting part, and is welded to form a second connecting part weld; both the first connecting part weld and the second connecting part weld are outer U-shaped bevels 24; refer to Figure 5 A schematic diagram of the U-shaped bevel on the outer side of the circumferential weld of the lower ring; refer to... Figure 6 A schematic diagram of the U-shaped bevel on the outer side of the circumferential weld of the upper crown; The first connecting weld includes an upper crown connecting annular weld 15, a lower ring connecting annular weld 16, and a blade connecting weld 17. The second connecting weld includes an upper crown connecting annular weld 18, a lower ring connecting annular weld 19, and a blade connecting weld 20. The upper crown connecting annular weld 15 is a butt weld between the outer circumferential surface of the upper crown inner ring 4 and the inner circumferential surface of the upper crown middle ring 9. The lower ring connecting annular weld 16 is a butt weld between the outer circumferential surface of the lower ring inner ring 5 and the lower ring middle ring 17. The butt welds on the inner circumferential surfaces are as follows: the blade connection weld 17 is the butt weld between the outer edge of the inner blade and the inner edge of the middle blade 11; the upper crown connection annular weld 18 is the butt weld between the outer circumferential surface of the upper crown middle ring 9 and the inner circumferential surface of the upper crown outer ring 12; the lower ring connection annular weld 19 is the butt weld between the outer circumferential surface of the lower ring middle ring 10 and the inner circumferential surface of the lower ring outer ring 13; and the blade connection weld 20 is the butt weld between the outer edge of the middle blade 11 and the inner edge of the outer blade 14. The weld of the first connecting part is entirely located on the first cylindrical surface 21, which is coaxial with the rotor, and the weld of the second connecting part is entirely located on the second cylindrical surface 22, which is coaxial with the rotor. The diameter of the first cylindrical surface 21 is smaller than the diameter of the second cylindrical surface 22, and both the first cylindrical surface 21 and the second cylindrical surface 22 are located in the low stress zone of the rotor blade profile. The first cylindrical surface 21 is located at 50% of the radial length of the blade, and the second cylindrical surface 22 is located at 75% of the radial length of the blade.

[0034] The inner blade, middle blade 11, and outer blade 14 correspond one-to-one. The thickness of the inner blade, middle blade 11, and outer blade 14 is 150mm. The complete blade wrap angle is 80°. The inner blade, middle blade 11, and outer blade 14 smoothly transition at the joint. After being welded together in sequence, they form 30 complete rotor blades. The diameter of the overall upper crown after connecting the inner ring 4, middle ring 9, and outer ring 12 is 5000mm. The diameter of the overall lower ring after connecting the inner ring 5, middle ring 10, and outer ring 13 is 5000mm.

[0035] Example 4 As another preferred embodiment of the present invention, this embodiment provides a method for manufacturing a water turbine runner, comprising the following steps: S1. The rotor to be manufactured is coaxially divided into inner ring section 1, middle ring section 2 and outer ring section 3 along the radial direction of the rotor. S2. The rotor middle ring section 2 is integrally cast and made of martensitic stainless steel to obtain a rotor middle ring section 2 with an integrally formed upper crown middle ring 9, middle blade 11 and lower ring middle ring 10. S3. The outer ring section 3 of the rotor is integrally cast and made of martensitic stainless steel to obtain an outer ring section 3 of the rotor with an integrally formed upper crown outer ring 12, outer blade 14 and lower ring outer ring 13. S4. The inner ring section 1 of the rotor is cast in two parts. Martensitic stainless steel is selected to form the upper crown inner blade disk blank and the lower ring inner blade disk blank respectively. After being independently precision machined, they are positioned and assembled by three sets of axial pin sleeves evenly distributed along the circumference of the rotor at 120°. The upper crown inner blade 6 and the lower ring inner blade 7 are connected one by one and fixed by X-shaped groove welding. Then, the first stress-relieving annealing is performed to obtain the inner ring section 1 of the rotor. S5. Using the design axis of the wheel as a reference, the inner ring section 1, the middle ring section 2, and the outer ring section 3 of the wheel are coaxially assembled in the radial direction from the inside to the outside. Three sets of radial positioning pins evenly distributed along the circumference of the wheel are used for reference positioning, so that the outer circumferential surface of the inner ring section 1 and the inner circumferential surface of the middle ring section 2 of the wheel are connected to form the first connection part, and the outer circumferential surface of the middle ring section 2 and the inner circumferential surface of the outer ring section 3 of the wheel are connected to form the second connection part. S6. First, weld the first connecting part and the second connecting part to form the first connecting part weld. The first connecting part weld includes the upper crown connecting annular weld 15, the lower ring connecting annular weld 16, and the blade connecting weld 17. The upper crown connecting annular weld 15 and the lower ring connecting annular weld 16 are argon arc welded on the outside of the wheel space by a robot to achieve single-sided welding and double-sided forming. Then, the robot performs gas shielded welding to avoid internal cavity welding. The blade connecting weld 17 is argon arc welded on the outside of the wheel by rotating the wheel 90° to a horizontal position and using a robot with a special long rod welding gun with a length of 500mm and a diameter of 30mm. Then, gas shielded welding is performed. After the first connecting part weld is completed, a second stress-relieving annealing treatment is performed. Next, the second connecting part is welded to form the second connecting part weld, which includes the upper crown connecting annular weld 18, the lower ring connecting annular weld 19, and the blade connecting weld 20. The upper crown connecting annular weld 18 and the lower ring connecting annular weld 19 are welded by a robot on the outside of the rotor space using argon arc welding to achieve single-sided welding and double-sided forming, followed by gas shielded welding by a robot, thus avoiding internal cavity welding. The blade connecting weld 20 is welded by rotating the rotor 90° to a horizontal position, using a specially designed long-rod welding gun (500mm long, 30mm diameter) via a robot for argon arc welding, followed by gas shielded welding. After the first connecting part weld is completed, a third stress-relieving annealing treatment is performed to weld the inner ring section 1, the middle ring section 2, and the outer ring section 3 of the rotor into one piece. After welding, the blade weld and the annular weld are processed and transitioned, referring to... Figure 7 The turbine runner was obtained.

Claims

1. A water turbine runner, characterized in that: It includes the inner ring section (1), the middle ring section (2), and the outer ring section (3) of the rotor; The inner ring section (1) of the rotor includes an upper crown inner blade disk and a lower ring inner blade disk welded together. The upper crown inner blade disk includes an upper crown inner ring (4) and an upper crown inner blade (6). The upper crown inner ring (4) and the upper crown inner blade (6) are integrally cast. The lower ring inner blade disk includes a lower ring inner ring (5) and a lower ring inner blade (7). The lower ring inner ring (5) and the lower ring inner blade (7) are integrally cast. The upper crown inner blade (6) and the lower ring inner blade (7) are connected and welded to form an inner blade weld (8) to form several complete inner blades. The wheel's middle ring section (2) includes an upper crown middle ring (9), a lower ring middle ring (10), and several middle blades (11) located between the upper crown middle ring (9) and the lower ring middle ring (10) and evenly distributed along the circumference. The upper crown middle ring (9), the lower ring middle ring (10), and the middle blades (11) are integrally cast. The outer ring section (3) of the wheel includes an upper crown outer ring (12), a lower ring outer ring (13), and a number of outer blades (14) located between the upper crown outer ring (12) and the lower ring outer ring (13) and evenly distributed along the circumference. The upper crown outer ring (12), the lower ring outer ring (13), and the outer blades (14) are integrally cast. The outer circumferential surface of the inner ring section (1) of the rotor is connected to the inner circumferential surface of the middle ring section (2) of the rotor to form a first connecting part, and is welded to form a first connecting part weld; the outer circumferential surface of the middle ring section (2) of the rotor is connected to the inner circumferential surface of the outer ring section (3) of the rotor to form a second connecting part, and is welded to form a second connecting part weld. The first connecting weld includes an upper crown connecting annular weld one (15), a lower ring connecting annular weld one (16) and a blade connecting weld one (17), and the second connecting weld includes an upper crown connecting annular weld two (18), a lower ring connecting annular weld two (19) and a blade connecting weld two (20). The first connecting weld forms a first cylindrical surface (21) around the central axis of the rotating wheel. The projection of the generatrix of the first cylindrical surface (21) in the vertical direction is parallel to the central axis of the rotating wheel. The second connecting weld forms a second cylindrical surface (22) around the central axis of the rotating wheel. The projection of the generatrix of the second cylindrical surface (22) in the vertical direction is parallel to the central axis of the rotating wheel. The diameter of the first cylindrical surface (21) is smaller than the diameter of the second cylindrical surface (22).

2. A turbine runner according to claim 1, characterized in that: The first cylindrical surface (21) is located at 45% to 55% of the radial length of the blade, and the second cylindrical surface (22) is located at 70% to 80% of the radial length of the blade.

3. A turbine runner according to claim 1, characterized in that: The welding grooves between the upper crown inner blade disk and the lower ring inner blade disk, between the middle blade (11) and the outer blade (14), and between the middle blade (11) and the inner blade are X-shaped grooves (23), and the welds of the first connection part and the welds of the second connection part are outer U-shaped grooves (24).

4. A turbine runner according to claim 1, characterized in that: The first annular weld of the upper crown is a butt weld between the outer circumferential surface of the inner ring (4) of the upper crown and the inner circumferential surface of the middle ring (9) of the upper crown. The first annular weld of the lower ring is a butt weld between the outer circumferential surface of the inner ring (5) of the lower ring and the inner circumferential surface of the middle ring (10) of the lower ring. The first blade weld is a butt weld between the outer edge of the inner blade and the inner edge of the middle blade (11). The second annular weld of the upper crown is a butt weld between the outer circumferential surface of the middle ring (9) of the upper crown and the inner circumferential surface of the outer ring (12) of the upper crown. The second annular weld of the lower ring is a butt weld between the outer circumferential surface of the middle ring (10) of the lower ring and the inner circumferential surface of the outer ring (13) of the lower ring. The second blade weld is a butt weld between the outer edge of the middle blade (11) and the inner edge of the outer blade (14).

5. A turbine runner according to claim 1, characterized in that: The inner blade, middle blade (11) and outer blade (14) correspond one-to-one. The inner blade, middle blade (11) and outer blade (14) smoothly transition at the joint and are welded together in sequence to form a complete rotor blade.

6. A turbine runner according to claim 1, characterized in that: The number of inner blades, middle blades (11) and outer blades (14) are all 9-30.

7. A turbine runner according to claim 1, characterized in that: The thickness of the inner blade, middle blade (11) and outer blade (14) is 10mm-150mm.

8. A turbine runner according to claim 1, characterized in that: The inner cavity height of the rotor is 50mm-250mm.

9. A turbine runner according to claim 1, characterized in that: The wrap angle of the complete blade is 30°-180°.

10. A turbine runner according to claim 1, characterized in that: The diameter of the overall upper crown after connecting the inner ring (4), middle ring (9) and outer ring (12) is 500mm-5000mm; the diameter of the overall lower ring after connecting the inner ring (5), middle ring (10) and outer ring (13) is 500mm-5000mm.

11. A method for manufacturing a water turbine runner, characterized in that, Includes the following steps: S1. The rotor to be manufactured is coaxially divided into an inner ring section (1), a middle ring section (2), and an outer ring section (3) along the radial direction of the rotor. S2. The rotor middle ring section (2) is integrally cast to obtain a rotor middle ring section (2) with an integrally formed upper crown middle ring (9), middle blade (11) and lower ring middle ring (10). S3. The outer ring section (3) of the rotor is integrally cast to obtain an outer ring section (3) of the rotor with an integrally formed upper crown outer ring (12), outer blade (14) and lower ring outer ring (13). S4. The inner ring section (1) of the rotor is separately cast, and the upper crown inner blade disk blank and the lower ring inner blade disk blank are cast separately. After being independently precision machined, the two are positioned, assembled and welded, and then stress-relief annealing is performed to obtain the inner ring section (1) of the rotor. S5. Based on the design axis of the wheel, the inner ring section (1), the middle ring section (2) and the outer ring section (3) of the wheel are coaxially assembled in the radial direction from the inside to the outside. The outer circumferential surface of the inner ring section (1) of the wheel is connected to the inner circumferential surface of the middle ring section (2) of the wheel to form the first connecting part. The outer circumferential surface of the middle ring section (2) of the wheel is connected to the inner circumferential surface of the outer ring section (3) of the wheel to form the second connecting part. S6. The first connecting part and the second connecting part are welded in sequence. After the first connecting part weld is formed, a second stress-relief annealing treatment is performed. After the second connecting part weld is formed, a third stress-relief annealing treatment is performed. The inner ring section (1), the middle ring section (2) and the outer ring section (3) of the turbine are welded into one piece to obtain the turbine runner.

12. A method for manufacturing a turbine runner according to claim 11, characterized in that: In S4, during positioning and assembly, the inner blade disk of the upper crown and the inner blade disk of the lower ring are positioned by axial pin sleeves. Three sets of axial pin sleeves are provided and evenly distributed along the circumference of the wheel at 120°.

13. A method for manufacturing a turbine runner according to claim 11, characterized in that: In S5, during coaxial assembly, the inner ring section (1), middle ring section (2), and outer ring section (3) of the wheel are positioned by radial positioning pins. Three sets of radial positioning pins are provided and evenly distributed along the circumference of the wheel at 120°.

14. A method for manufacturing a turbine runner according to claim 11, characterized in that: In S6, the first connecting weld includes an upper crown connecting annular weld one (15), a lower ring connecting annular weld one (16) and a blade connecting weld one (17), and the second connecting weld includes an upper crown connecting annular weld two (18), a lower ring connecting annular weld two (19) and a blade connecting weld two (20).

15. A method for manufacturing a turbine runner according to claim 14, characterized in that: When the upper crown connecting annular weld seam one (15), the lower ring connecting annular weld seam one (16), the upper crown connecting annular weld seam two (18), and the lower ring connecting annular weld seam two (19) are connected, a robot is used to perform argon arc welding on the outside of the wheel space, with single-sided welding and double-sided forming, and then a robot is used for gas shielded welding; when the blade connecting weld seam one (17) and the blade connecting weld seam two (20) are connected, the wheel is rotated 90° to a horizontal position, and a special long-rod welding gun is used to perform argon arc welding on the bottom layer by a robot, with single-sided welding and double-sided forming, and then a robot is used for gas shielded welding.

16. A method for manufacturing a turbine runner according to claim 15, characterized in that: The specially designed long-rod welding torch is 450mm-550mm long and 25mm-35mm in diameter.

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