Impact type rotating wheel hollow water bucket structure and manufacturing method thereof

Abstract

The invention discloses an impact type rotating wheel hollow water bucket structure and a manufacturing method thereof, and relates to the technical field of hydroelectric power generation, in particular to the manufacturing method of the impact type rotating wheel hollow water bucket structure, which comprises the following steps: S1, preparing an impact type rotating wheel hub and a water bucket root solid area through forging, milling, polishing and other process means; s2, calculating a water bucket hollow part model through the working stress of the rotating wheel; and S3, the prepared rotating wheel hub is clamped to a positioner, and according to the model calculated in the above steps, the additive manufacturing of the rotating wheel hollow water bucket is achieved by continuously and cooperatively adjusting the spatial position of the rotating wheel and the posture of a welding gun. The invention has the advantages of reducing the weight, improving the stability, reducing the inertia, prolonging the service life, saving the cost, promoting the sustainable development, optimizing the structural design, improving the performance, improving the efficiency, reducing the energy consumption, being convenient to manufacture and maintain and enhancing the adaptability.

Description

Technical Field

[0001] The invention relates to the technical field of hydropower generation, and in particular to an impact-type runner hollow bucket structure and a manufacturing method thereof. Background Art

[0002] The impulse turbine is a highly efficient hydraulic prime mover, widely used in power stations with high head and small flow. Its working principle is to use a special water guide mechanism to draw out a free jet with kinetic energy, which rushes towards the runner bucket, causing the runner to rotate and do work, thereby converting water energy into mechanical energy. According to the relative position of the working jet and the runner and the number of working times, the impulse turbine can be divided into a tangential impulse turbine, an oblique impulse turbine and a double impulse turbine.

[0003] As the core component of the impulse turbine, the design and manufacture of the runner have a crucial impact on the performance and efficiency of the entire unit. The runner is usually composed of a hub and a bucket, where the bucket directly bears the impact force of the high-speed water flow. In order to meet the high-strength requirements, the traditional impulse runner design adopts a solid structure. However, the solid structure runner has the following problems:

[0004] 1. Large mass and high static load: The solid structure runner has a large mass, which causes the main shaft supporting the runner to be subjected to a large static load, increasing the burden on the supporting components and reducing the structural stability of the unit.

[0005] 2. Large inertia and high centrifugal force: During the high-speed rotation of the impeller, the inertia force generated by the solid structure impeller is relatively large, which increases the centrifugal force on the root of the bucket and affects the service life of the impeller.

[0006] 3. Material waste and high cost: Solid structure runners require a lot of raw materials, which not only increases manufacturing costs but also does not meet the requirements of sustainable development. Summary of the invention

[0007] The present invention aims to overcome the above-mentioned shortcomings of the prior art and provides an impact type runner hollow water bucket structure and a manufacturing method thereof.

[0008] The technical solution adopted by the present invention is as follows:

[0009] An impact wheel hollow bucket structure comprises: a wheel hub and a bucket, wherein the bucket comprises a plurality of circular arrays arranged outside the wheel hub, and the bucket is provided with a hollow part and a solid part.

[0010] Furthermore, the water bucket includes a root water bucket and an external water bucket, the root water bucket is connected to the wheel hub, and the hollow part is arranged in the external water bucket.

[0011] Furthermore, the wall thickness of the hollow part of the water bucket is set to be more than 20 mm.

[0012] Furthermore, the two wings of the bucket are arranged to be solid.

[0013] Furthermore, a method for manufacturing an impact wheel hollow bucket structure comprises the following steps:

[0014] S1: Prepare the impact wheel hub and the solid area at the root of the bucket by forging, milling, grinding and other processes;

[0015] S2: Calculate the hollow part model of the bucket through the working stress of the runner;

[0016] S3: Clamp the prepared runner hub onto the positioner, and according to the model calculated in the above steps, realize the additive manufacturing of the runner hollow bucket by continuously and collaboratively adjusting the spatial position of the runner and the welding gun posture.

[0017] Furthermore, in step S2, the working stress of the runner bucket during operation is calculated based on the fluid-solid coupling finite element simulation, and the change value of the dynamic stress of each area of ​​the runner bucket over time is obtained.

[0018] Furthermore, the hollow portion is set to meet the condition: σ s ≥kσ w , where σ s is the material fatigue strength, σ w is the working stress value of each area of ​​the bucket calculated in step S2, and k is the coefficient.

[0019] Furthermore, the coefficient k is set to 5.

[0020] Furthermore, in step S3, after processing a section of the area, the inside of the hollow portion is polished, and the segmented material addition and polishing steps are repeated until the overall shape of the wheel is formed.

[0021] Furthermore, in the grinding step, a rounded transition process is performed on the sharp corners and narrow gap areas in the hollow portion.

[0022] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0023] 1. Reduce weight and improve stability: The bucket is designed as a hollow structure, which significantly reduces the mass of the external bucket, thereby reducing the mass of the entire runner. This not only reduces the static load on the main shaft supporting the runner, but also increases the structural stability of the impact unit and reduces deformation and vibration caused by deadweight.

[0024] 2. Reduce inertia and extend service life: The reduction in the total mass of the external hollow bucket reduces the inertial force generated by the impeller when it rotates at high speed, thereby reducing the centrifugal force on the root of the bucket. This not only increases the service life of the impact impeller, but also helps to reduce structural damage caused by fatigue.

[0025] 3. Save costs and promote sustainable development: After the outer bucket of the runner is hollowed out, the cost of raw materials is greatly saved, and the manufacturing and maintenance costs are reduced. This not only reduces resource consumption, but also reduces the production cost of the enterprise, which is conducive to the sustainable development of the hydropower industry.

[0026] 4. Optimize structural design and improve performance: Through precise calculation and optimized design, the wall thickness and structure of the hollow bucket are reasonably configured, ensuring that while reducing weight, sufficient strength and rigidity are maintained to meet the working requirements under complex force loads.

[0027] 5. Improve efficiency and reduce energy consumption: After reducing the mass of the runner, the energy consumption during the rotation process is reduced, which improves the overall efficiency of the turbine. At the same time, the hollow structure design helps to reduce the impact resistance of the water flow on the runner, further improving the performance of the turbine.

[0028] 6. Easy to manufacture and maintain: The hollow bucket structure adopts segmented additive manufacturing and grinding process, which is convenient for controlling manufacturing accuracy and quality.

[0029] 7. Enhanced adaptability: The hollow bucket structure can be adjusted and optimized according to different working conditions and design requirements, which enhances the adaptability and versatility of the runner. For example, the wall thickness and shape of the hollow part can be changed to meet the requirements of different water heads and flow rates. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a schematic diagram of the structure of the impact wheel of the present invention;

[0031] Figure 2 Schematic diagram of the external bucket structure of the impact type runner of the present invention;

[0032] Figure 3 is an overall view of the stress distribution of the runner of the present invention (colored);

[0033] Figure 4 It is a partial view (colored) of the stress distribution of the runner bucket of the present invention;

[0034] Figure 5 is the working stress simulation result of the solid bucket runner (colored);

[0035] Figure 6 It is the working stress simulation result of the hollow bucket runner of the present invention (colored);

[0036] Figure 7 It is an overall view of the stress distribution of the runner of the present invention;

[0037] Figure 8 This is a partial view of the stress distribution of the runner bucket of the present invention;

[0038] Fig. 9 It is the simulation result of working stress of solid bucket runner;

[0039] Fig.10 It is the working stress simulation result of the hollow bucket impeller of the present invention.

[0040] Markings in the figure:

[0041] 1-hub, 2-buoy, 3-hollow part, 4-solid part, 5-external bucket, 6-root bucket.

[0042] Specific Examples

[0043] The present invention will be described in detail below in conjunction with the accompanying drawings.

[0044] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0045] Embodiment 1

[0046] In this embodiment, if Figure 1 As shown, an impact wheel hollow bucket structure includes: a hub 1 and a bucket 2, the bucket 2 includes a plurality of circular arrays arranged on the outer side of the hub 1, and the bucket 2 is provided with a hollow part 3 and a solid part 4.

[0047] This design reduces the overall mass of the runner, reduces the static load on the main shaft, and improves the structural stability of the unit. At the same time, the hollow structure helps save raw material costs and reduce manufacturing and maintenance costs.

[0048] Furthermore, the scoop 2 includes a root scoop 62 and an external scoop 52 , the root scoop 62 is connected to the hub 1 , and the hollow portion 3 is disposed in the external scoop 52 .

[0049] This design concentrates the high stress area in the root bucket 62. The solid root provides the necessary strength and rigidity, while the hollow structure of the outer bucket 52 significantly reduces the mass and inertial forces.

[0050] Furthermore, the wall thickness of the hollow portion 3 of the water bucket 2 is set to be greater than 20 mm.

[0051] This ensures that the hollow bucket 2 maintains sufficient strength and rigidity while reducing its mass to meet working requirements under complex force loads.

[0052] Furthermore, the two wings of the bucket 2 are configured to be solid.

[0053] The solid two wings enhance the structural stability of the bucket 2, and can effectively prevent deformation and damage, especially when subjected to the impact of high-speed water flow.

[0054] Embodiment 2

[0055] Based on the first embodiment, a method for manufacturing an impact runner hollow bucket structure is provided, comprising the following steps:

[0056] S1: The impact wheel hub 1 and the solid root area of ​​the bucket 2 are prepared by forging, milling, grinding and other process methods;

[0057] S2: Calculate the model of the hollow part 3 of the bucket 2 through the working stress of the runner;

[0058] S3: Clamp the prepared runner hub 1 onto the positioner, and according to the model calculated in the above steps, realize the additive manufacturing of the runner hollow bucket 2 by continuously and collaboratively adjusting the spatial position of the runner and the welding gun posture.

[0059] Specifically, in this embodiment, in order to demonstrate the effect of the new hollow bucket 2 impeller, the working stress of the new hollow bucket 2 impeller and the original solid bucket 2 impeller is calculated by using the fluid-solid coupling finite element simulation technology. The simulation results are shown in Figure 5 , 6 or Fig. 9 , 10 middle. Figure 5 (9) and Figure 6 (10) represent the working stress simulation results of the solid bucket 2 and the hollow bucket 2 respectively. Figure 5 (9) It can be seen that the new hollow bucket 2 structure can significantly reduce the working stress of the impeller. The maximum stress at the root of the impeller is reduced from the original 15.6MPa to 12.8MPa, and the stress at the same position in the middle of the bucket 2 is reduced from the original 6.576MPa to 3.872MPa. In addition, the mass of the hollow bucket 2 impeller and the solid bucket 2 impeller in this example is calculated by CAD software, which is 4117.6kg and 5834.5kg respectively. The new hollow bucket 2 structure designed in this example saves about 29.4% of raw materials, which is in line with the purpose of sustainable development of the manufacturing industry.

[0060] When the hollow water bucket 2 is manufactured by additive manufacturing, a variety of additive methods can be used, such as laser, electric arc, submerged arc welding, etc.

[0061] This manufacturing method combines traditional craftsmanship with modern additive manufacturing technology to ensure the manufacturing accuracy and quality of the Water Bucket 2. At the same time, the segmented additive manufacturing and grinding process facilitates the control of the manufacturing process and reduces manufacturing costs.

[0062] Furthermore, in step S2, the working stress of the runner bucket 2 during operation is calculated based on the fluid-solid coupling finite element simulation, and the change value of the dynamic stress of each area of ​​the runner bucket 2 over time is obtained.

[0063] The working stress simulation results of the impact wheel are shown in Figure 3 (7) shows that the stress result shown in the figure is the maximum principal stress, and the simulation result shown is the moment of maximum stress when the wheel is working. Figure 3 (7) is the overall view of the maximum principal stress distribution results when the runner is working. Figure 4 (8) is a partial view of the working stress of the bucket 2. Figure 3 (7) It can be seen that the high stress area of ​​the impeller mainly appears at the place where the root of the bucket 2 is beveled at the impeller hub 1, while the overall working stress of the external bucket 52 is relatively small. The main reason for the high stress at the root of the bucket 2 is that when the impeller is working, the bucket blades are impacted by high-speed water flow, which causes a large bending moment at the root of the bucket 2. At the same time, the centrifugal force generated by the gravity of the bucket 2 and the high-speed rotation generates a large tensile stress at the root of the bucket 2. The maximum stress value at the root of the bucket 2 is about 15.6MPa. The working stresses at the ends and wings of the bucket 2 and the core of the bucket 2 are relatively small. According to the structural design steps of the hollow bucket 2 of the impeller, and considering the machinability of the hollow bucket 2, the boundary area between the hollow bucket 2 and the solid bucket 2 is finally determined as follows: Figure 4 as shown in (8).

[0064] Through precise numerical simulation, the stress distribution of the bucket 2 during operation can be accurately predicted, providing a scientific basis for optimal design.

[0065] Furthermore, the hollow portion 3 is arranged to satisfy the condition: σs≥kσw, wherein σs is the fatigue strength of the material, σw is the working stress value of each area of ​​the bucket 2 calculated in step S2, and k is a coefficient.

[0066] The material fatigue strength is the design fatigue strength of the manufacturing material of the water bucket 2. The working stress value is multiplied by the coefficient to ensure that it has a design margin under various working conditions to ensure the normal operation of the water bucket 2 after the hollow water bucket 2 is set.

[0067] The safety and reliability of the hollow bucket 2 under various working conditions are ensured, and structural failure due to fatigue is prevented.

[0068] Furthermore, the coefficient k is set to 5.

[0069] This safety factor provides the best design margin to ensure the performance and economy of the Bucket 2 under extreme working conditions.

[0070] Furthermore, in step S3, after processing a section of the area, the inside of the hollow portion 3 is polished, and the step of segmented material addition and polishing is repeated until the overall shape of the wheel is formed.

[0071] The segmented manufacturing and grinding process helps to control the manufacturing accuracy and ensure the surface quality and internal structural strength of the bucket 2.

[0072] Furthermore, in the grinding step, the sharp corners and narrow gap areas in the hollow portion 3 are subjected to rounded transition processing.

[0073] The rounded corner transition treatment reduces stress concentration points, improves the fatigue resistance of the bucket 2, and prolongs its service life.

[0074] The above description is only a preferred embodiment of the invention and is not intended to limit the invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the invention should be included in the protection scope of the invention.

Claims

1. An impact wheel hollow bucket structure, characterized in that: include: A wheel hub (1) and a water bucket (2), wherein the water bucket (2) comprises a plurality of circular arrays arranged outside the wheel hub (1), and the water bucket (2) is provided with a hollow portion (3) and a solid portion (4).

2. According to the impact wheel hollow bucket structure of claim 1, it is characterized by: The water bucket (2) comprises a root water bucket (6) (2) and an external water bucket (5) (2), wherein the root water bucket (6) (2) is connected to the wheel hub (1), and the hollow portion (3) is arranged on the external water bucket (5) (2).

3. The method for manufacturing an impact wheel hollow bucket structure according to claim 1, characterized in that: The wall thickness of the hollow portion (3) of the water bucket (2) is set to be greater than 20 mm.

4. The method for manufacturing an impact wheel hollow bucket structure according to claim 1, characterized in that: The two wings of the water bucket (2) are arranged to be solid.

5. A method for manufacturing an impact runner hollow bucket structure, applied to an impact runner hollow bucket structure according to any one of claims 1 to 4, characterized in that: The following steps are involved: S1: preparing the impact wheel hub (1) and the solid root area of ​​the bucket (2) by forging, milling, grinding and other process methods; S2: Calculate the model of the hollow part (3) of the bucket (2) through the working stress of the runner; S3: Clamp the prepared runner hub (1) onto a positioner, and according to the model calculated in the above steps, realize additive manufacturing of the runner hollow bucket (2) by continuously and collaboratively adjusting the spatial position of the runner and the welding gun posture.

6. The method for manufacturing an impact wheel hollow bucket structure according to claim 5, characterized in that: In the step S2, the magnitude of the working stress of the runner bucket (2) during operation is calculated based on the fluid-solid coupling finite element simulation, and the value of the dynamic stress of each area of ​​the runner bucket (2) changing with time is obtained.

7. The method for manufacturing a hollow bucket structure of an impact runner according to claim 5, characterized in that: The hollow portion (3) is arranged to satisfy the condition: σs≥kσw, wherein σs is the material fatigue strength, σw is the working stress value of each area of ​​the bucket (2) calculated in step S2, and k is a coefficient.

8. The method for manufacturing a hollow bucket structure of an impact runner according to claim 7, characterized in that: The coefficient k is set to 5.

9. The method for manufacturing a hollow bucket structure of an impact runner according to claim 5, characterized in that: In the step S3, after processing a section of the area, the inside of the hollow part (3) is polished, and the step of segmented material addition and polishing is repeated until the overall shape of the wheel is formed.

10. The method for manufacturing a hollow bucket structure of an impact runner according to claim 9, characterized in that: In the polishing step, a rounded transition process is performed on the sharp corners and narrow gap areas existing in the hollow portion (3).

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