Water turbine impeller structure, manufacturing method thereof and water turbine comprising water turbine impeller structure

Abstract

The invention belongs to the technical field of water turbines, and particularly relates to a water turbine impeller structure and a water turbine comprising the water turbine impeller structure. Each wheel blade single body comprises a blade part and a connecting part, and the blade parts and the connecting parts are integrally formed. The blade part is used for forming a water bucket structure; and the connecting part is used for forming a wheel disc structure. The connecting parts of the wheel blade single bodies are integrally in a wedge shape, and a complete wheel disc structure is formed after each set of connecting parts with the designed number are spliced. According to the water turbine impeller structure, the problems that in a traditional cast-weld combined structure, the root of a bucket of an impeller is large in welding stress and prone to fatigue fracture are solved. The wheel blade single bodies can be produced in various modes such as casting, stamping or 3D printing; compared with an integrally cast impeller, the material cost, the machining cost and the transportation cost are greatly reduced; and the assembly parts are single, the assembly process is simplified, the production efficiency is improved, and the cost advantage is huge.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of hydraulic turbine, in particular to a hydraulic turbine impeller structure, a manufacturing method thereof and a hydraulic turbine containing the same. BACKGROUND

[0002] As the core power device for converting fluid kinetic energy into mechanical energy, the performance of the hydraulic turbine directly affects the energy conversion efficiency and equipment operation reliability in the fields of hydroelectric power generation, industrial circulating water driving and pump station. The impeller (or runner) as the core power component of the hydraulic turbine, its structural design and manufacturing process directly determine the performance level, service life and economy of the whole machine.

[0003] At present, the main structural form of the impeller in the bucket type hydraulic turbine can be divided into two types: integral casting type and cast-welding combined type. The integral casting type integrates the bucket and the disc into one, avoiding potential defects caused by the welding interface, and has the advantages of simple structure, high structural integrity, uniform mechanical properties, high strength, etc. However, it requires high casting technology level, the casting process is extremely complex, and the arrangement of the buckets is dense, which makes the machining of the bucket surface extremely difficult and prone to casting defects. At the same time, the integral casting has low material utilization rate, long manufacturing cycle, high cost, and is prone to product deformation. In addition, it can only be transported as a whole, which is difficult to transport. Moreover, its maintainability is extremely poor, and the damage of any single bucket means the scrap of the whole runner.

[0004] The cast-weld combined structure is that single cast water buckets are processed according to requirements and then are combined with the runner to form a whole; the runner structure has the characteristics of easy manufacturing, accurate guarantee of the shape of the water bucket, easy processing, thus easy guarantee of the runner with high hydraulic efficiency, and low production cost, but the runner with the cast-weld structure has the defects that cracks are prone to occur at the root of the water bucket and the welding position of the runner, the welding quality is not easy to control, and the welding residual stress is not easy to eliminate, so the strength of the root of the water bucket of the runner with the cast-weld structure is poor, especially the single water bucket in the runner is only welded together with the runner by the root, the water flow is shot on the water bucket, the water bucket is equivalent to a single cantilever body, is subjected to the impact force of the water flow and the centrifugal force generated by the rotation of the runner, the stress condition is poor, the root of the water bucket is prone to cracks and the cracks are prone to expand, thus the water bucket is prone to break and fly out during operation. Therefore, the impeller with the cast-weld structure usually needs to be strengthened according to the structure of the water bucket. For example, the water bucket type water turbine runner disclosed in CN2806806Y comprises a runner and water bucket groups which are uniformly distributed on the circumference of the hub of the runner and are combined with the runner into an integral whole, two circular hoops are further combined with the outer periphery of the bucket part of each water bucket group, the inner periphery of the circular hoop is welded with the outer periphery of the bucket part of each water bucket group, one circular hoop is combined with the two sides of the root of each water bucket, and the inner and outer peripheries of the circular hoop are welded with the end surface of each water bucket root. In the scheme, the runner, the water bucket and the circular hoop are organically combined into an integral whole through the circular hoop to improve the strength of the root of the water bucket. For another example, the impeller of the impulse water turbine disclosed in CN1715640A has the characteristic that at least one hoop is arranged on the outer circle of the runner, the hoop connects the adjacent water buckets with each other, the hoop is a circular hoop and is arranged at the maximum radius of the runner. The advantage is that the stress condition of the water bucket is changed without changing the traditional structure and production process of the impulse runner, thus the problem that the water bucket is prone to fatigue cracks and then to break is solved. However, the strengthening scheme of "welding for reinforcement" cannot fundamentally break through the limitation of the cast-weld combined structure, that is, the risk of fatigue of the root of the water bucket cannot be completely eliminated. Instead, the complexity of the structure and the manufacturing cost are increased.

[0005] In summary, the two structures of the traditional water bucket type water turbine runner have their preferred application scenarios, and also have defects that cannot be overcome: therefore, a new runner structure of a water turbine and a manufacturing method thereof need to be developed; the inherent problem of insufficient strength of the root of the water bucket in the combined structure can be overcome, and the production cost and control can be significantly better than the integral cast structure. SUMMARY

[0006] The purpose of the present application is to overcome the above-mentioned defects of the prior art and provide a runner structure of a water turbine and a water turbine containing the same, which can overcome the problem of insufficient strength of the root of the water bucket in the combined structure, and can also reduce the production cost.

[0007] To achieve the above object, the present application firstly provides a water turbine impeller structure which is assembled by a plurality of wheel blade monomers with the same shape; the wheel blade monomer comprises a blade part and a connecting part, and the blade part and the connecting part are integrally formed; the blade part is used to form a bucket structure; and the connecting part is used to form a disc structure.

[0008] Further, the connecting part of the wheel blade monomer is in the shape of a whole wedge, and a designed number of connecting parts in each group form a complete disc structure after being spliced.

[0009] Further, the connecting part is provided with a protrusion and a groove on the inclined surfaces on the left and right sides, respectively; and the positioning and limiting are realized by the protrusion and the groove between the adjacent connecting parts during the assembly of the wheel blade monomers. In some specific embodiments, the connecting part of the wheel blade monomer can also be designed with other forms of mortise and tenon type structure, so as to facilitate the splicing of the wheel blade monomers. For example, the semicircular grooves are arranged on the inclined surfaces on the left and right sides of the connecting part, and the two semicircular grooves on the adjacent connecting parts are spliced into a complete circular hole during splicing, and then the pin column is inserted into the complete circular hole, so as to realize the splicing and fixing of the wheel blade monomers.

[0010] Further, the connecting part is provided with a protrusion and a groove on the inclined surfaces on the left and right sides, respectively; and the positioning and limiting are realized by the protrusion and the groove between the adjacent connecting parts during the assembly of the wheel blade monomers. In some specific embodiments, the connecting part of the wheel blade monomer can also be designed with other forms of mortise and tenon type structure, so as to facilitate the splicing of the wheel blade monomers. For example, the semicircular grooves are arranged on the inclined surfaces on the left and right sides of the connecting part, and the two semicircular grooves on the adjacent connecting parts are spliced into a complete circular hole during splicing, and then the pin column is inserted into the complete circular hole, so as to realize the splicing and fixing of the wheel blade monomers.

[0011] Further, the connecting part is provided with a protrusion and a groove on the inclined surfaces on the left and right sides, respectively; and the positioning and limiting are realized by the protrusion and the groove between the adjacent connecting parts during the assembly of the wheel blade monomers. In some specific embodiments, the connecting part of the wheel blade monomer can also be designed with other forms of mortise and tenon type structure, so as to facilitate the splicing of the wheel blade monomers. For example, the semicircular grooves are arranged on the inclined surfaces on the left and right sides of the connecting part, and the two semicircular grooves on the adjacent connecting parts are spliced into a complete circular hole during splicing, and then the pin column is inserted into the complete circular hole, so as to realize the splicing and fixing of the wheel blade monomers.

[0012] Further, the connecting part is provided with a protrusion and a groove on the inclined surfaces on the left and right sides, respectively; and the positioning and limiting are realized by the protrusion and the groove between the adjacent connecting parts during the assembly of the wheel blade monomers. In some specific embodiments, the connecting part of the wheel blade monomer can also be designed with other forms of mortise and tenon type structure, so as to facilitate the splicing of the wheel blade monomers. For example, the semicircular grooves are arranged on the inclined surfaces on the left and right sides of the connecting part, and the two semicircular grooves on the adjacent connecting parts are spliced into a complete circular hole during splicing, and then the pin column is inserted into the complete circular hole, so as to realize the splicing and fixing of the wheel blade monomers.

[0013] Further, the connecting part is provided with a protrusion and a groove on the inclined surfaces on the left and right sides, respectively; and the positioning and limiting are realized by the protrusion and the groove between the adjacent connecting parts during the assembly of the wheel blade monomers. In some specific embodiments, the connecting part of the wheel blade monomer can also be designed with other forms of mortise and tenon type structure, so as to facilitate the splicing of the wheel blade monomers. For example, the semicircular grooves are arranged on the inclined surfaces on the left and right sides of the connecting part, and the two semicircular grooves on the adjacent connecting parts are spliced into a complete circular hole during splicing, and then the pin column is inserted into the complete circular hole, so as to realize the splicing and fixing of the wheel blade monomers.

[0014] Further, the connecting part is provided with a protrusion and a groove on the inclined surfaces on the left and right sides, respectively; and the positioning and limiting are realized by the protrusion and the groove between the adjacent connecting parts during the assembly of the wheel blade monomers. In some specific embodiments, the connecting part of the wheel blade monomer can also be designed with other forms of mortise and tenon type structure, so as to facilitate the splicing of the wheel blade monomers. For example, the semicircular grooves are arranged on the inclined surfaces on the left and right sides of the connecting part, and the two semicircular grooves on the adjacent connecting parts are spliced into a complete circular hole during splicing, and then the pin column is inserted into the complete circular hole, so as to realize the splicing and fixing of the wheel blade monomers.

[0015] The present application also provides a water turbine which adopts the above-mentioned impeller structure.

[0016] The present application also provides a manufacturing method of the above-mentioned water turbine impeller structure, comprising the following steps: 1) sequentially splicing a designed number of wheel blade monomers to make the protrusions and the grooves on the left and right side inclined surfaces of the connecting parts sequentially match, and initially forming a disc structure; 2) forming a gap between the adjacent two connecting parts in the initially formed disc structure, and welding at the gap; and initially welding all the connecting parts together; 3) After the preliminary welding of the wheel disc structure, the upper and lower outer surfaces are flattened, and the counterweight ring is installed into the flattened annular step groove; and the remaining part of the annular step groove is filled using the surfacing process to improve the overall connection strength of the wheel disc structure; preferably, the thickness of the counterweight ring can be greater than the maximum depth of the annular step groove, so that the workload is less when filling the annular step groove, and the welding material is also saved; 4) The center of the wheel disc structure is processed to form a hole structure for assembling the corresponding rotating shaft.

[0017] Compared with the prior art, the beneficial effects of the present application are: 1、The water turbine impeller structure provided by the present application is integrally assembled by a plurality of wheel blade monomers, the wheel blade monomer comprises a blade part and a connecting part, the blade part and the connecting part are integrally formed, the blade part and the connecting part form a bucket group and a wheel disc structure respectively, and the problem of large welding stress and easy fatigue fracture of the bucket root of the impeller in the traditional cast-weld combined structure is avoided.

[0018] 2、The wheel blade monomer of the present application is very suitable for modularization, standardization and large-scale production, and the wheel blade monomer can be produced in various ways such as forging forming, casting forming or metal additive manufacturing (such as casting, stamping or 3D printing). Especially when the wheel blade monomer is produced by forging forming, the strength, hardness and toughness of the product are excellent after hammering, extruding, rolling and quenching, and the machining precision of the forging forming is also extremely high. In addition, in the prior art, the overall cast forming of the impeller structure is prone to deformation, which is not conducive to subsequent processing; while in the present application, the wheel blade monomer is cast formed and then spliced, which not only reduces the cost, but also makes the subsequent processing of the wheel blade monomer more convenient and better guarantees the quality of the final impeller structure product.

[0019] 3、The impeller structure of the present application has single assembly parts and does not exist the cooperation between multiple complex parts, so the assembly process is greatly simplified, the dependence on senior technicians is greatly reduced, the production efficiency and consistency are improved, and there is a great cost advantage in mass production.

[0020] 4、The water turbine impeller structure of the present application is spliced by monomers, so when a certain wheel blade monomer is damaged, only the damaged part needs to be replaced during maintenance, thereby reducing the maintenance cost. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 It is a schematic diagram of the impeller in the embodiment of the present application; Figure 2 It is a perspective view of the embodiment of the present application after omitting part of the wheel blade monomers; Figure 3 It is a front view and a sectional view of A-A of the embodiment of the present application after omitting part of the wheel blade monomers; Figure 4 This is a three-dimensional schematic diagram of a single impeller unit in an embodiment of the present invention; Figure 5 This is a schematic cross-sectional view of a single impeller unit in an embodiment of the present invention; Figure 6 This is a schematic diagram of the impeller in Embodiment 2 of the present invention; In the diagram: 1. Blade section; 2. Connecting section; 21. Protrusion; 22. Groove; 23. Stepped groove; 3. Counterweight ring; 4. Bevel; 5. Pin. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this invention clearer, the invention is described below through specific embodiments. However, it should be understood that these descriptions are merely exemplary and not intended to limit the scope of the invention. The structures, proportions, sizes, etc., illustrated in the accompanying drawings are only for illustrative purposes and to enable those skilled in the art to understand and read the invention, and are not intended to limit the conditions under which the invention can be implemented. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to size, without affecting the effects and objectives achieved by the invention, should still fall within the scope of the technical content disclosed in this invention.

[0023] Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concepts in this invention.

[0024] Example 1

[0025] like Figures 1-5 As shown, this embodiment is a turbine impeller structure, which is assembled from multiple identical impeller units. Each impeller unit includes a blade portion 1 and a connecting portion 2, and the blade portion 1 and the connecting portion 2 are integrally formed. The blade portion 1 is used to form a water bucket structure; the connecting portion 2 is used to form a disc structure. In this embodiment, the connecting portion 2 of the impeller unit is generally wedge-shaped, and each set of designed number of connecting portions 2, after being spliced, forms a complete disc structure. The connecting portion 2 has protrusions 21 and grooves 22 on its left and right inclined surfaces, respectively; during the assembly of the impeller units, adjacent connecting portions 2 can be positioned and limited by the protrusions 21 and grooves 22. Stepped grooves 23 are provided on the front and rear end faces of the connecting portion 2. After the connecting portions 2 are assembled into a disc structure, the stepped grooves 23 can be spliced ​​into an annular stepped groove.

[0026] In this embodiment, the stepped groove includes two steps, and the formed annular stepped groove also includes two steps. A counterweight ring 3 is provided in the deepest step of the annular stepped groove. The counterweight ring 3 is mainly used to increase the rotational inertia of the impeller, and also has protective and aesthetic functions.

[0027] In this embodiment, chamfers are provided on the edges of the connecting parts 2 of the blade unit. The chamfers are used to form a bevel 4 for welding when the connecting parts 2 are spliced ​​together.

[0028] In this embodiment, the blade section 1 is a double-cavity water bucket, and the part where the blade section 1 and the connecting part 2 are connected is a solid structure.

[0029] In this embodiment, the impeller unit is produced by casting, metal additive manufacturing, or forging.

[0030] This embodiment describes a method for assembling and manufacturing a turbine impeller structure, which specifically includes the following steps: 1) First, prepare the designed number of integrally molded impeller units, and then splice these impeller units in sequence so that the protrusions 21 and grooves 22 on the left and right inclined surfaces of the connecting part 2 fit together in sequence to initially splice and form a disc structure. 2) In the initially formed disc structure, since the blade unit has a chamfer on its edge, a bevel 4 will be formed at the joint between two adjacent connecting parts 2. Welding is carried out at the bevel 4 to initially weld all connecting parts 2 together. 3) Level the upper and lower outer surfaces of the wheel structure after preliminary welding, and then install the counterweight ring 3 into the bottom annular step groove after leveling; then fill the annular step groove with a welding process. 4) The center part of the wheel structure is machined to form a hole structure for assembling the corresponding rotating shaft.

[0031] Example 2

[0032] like Figure 6 As shown, the main difference between this embodiment and embodiment 1 is that the connecting part 2 of the impeller unit in this embodiment adopts a different mortise and tenon structure. Specifically, semi-circular grooves 22 are provided on both sides of the connecting part 2. When splicing, the two semi-circular grooves 22 on the two adjacent connecting parts 2 can be spliced ​​into a complete round hole. Then, the pin 5 is inserted into the complete round hole to achieve the initial splicing of the impeller unit.

[0033] In other embodiments, the connecting parts can use mortise and tenon structures of other shapes, as long as they can achieve a stable splicing between the connecting parts.

[0034] Example 3

[0035] This embodiment provides a water turbine that adopts the impeller structure of Embodiment 1. Due to the adoption of the impeller structure of Embodiment 1, the water turbine in this embodiment also has a corresponding cost advantage.

[0036] The above merely describes some embodiments of the present application, and is not intended to limit the present application. Those skilled in the art can make various combinations and modifications of the foregoing technical features, and make improvements and variations to the present application without departing from the spirit and scope of the present application. Improvements, variations, equivalent replacements, or the use of the structure or method of the present application in other fields to achieve the same purpose, all belong to the protection scope of the present application.

Claims

1. A structure of a runner of a hydraulic turbine, characterized by: The impeller is assembled by a plurality of identical impeller units; the impeller unit comprises a blade part and a connecting part, and the blade part and the connecting part are integrally formed; the blade part is used to form a bucket structure; and the connecting part is used to form a disc structure.

2. The water turbine impeller structure according to claim 1, characterized by: The connecting part of the impeller unit is wedge-shaped as a whole, and a designed number of connecting parts in each group are spliced to form a complete disc structure.

3. The water turbine impeller structure according to claim 2, characterized by: The connecting part is provided with a protrusion and a groove on the left and right inclined surfaces respectively; when the impeller units are assembled, the adjacent connecting parts are positioned and limited by the protrusion and the groove; or the connecting part is provided with a corresponding mortise-tenon structure on the left and right inclined surfaces, and the mortise-tenon structure is used to splice the connecting parts.

4. The water turbine impeller structure according to claim 2, characterized by: The connecting part is provided with a stepped groove on the front and rear end surfaces, and the stepped groove is spliced into an annular stepped groove after the connecting parts form the disc structure.

5. The water turbine impeller structure according to claim 4, characterized by: The annular stepped groove is provided with a counterweight ring; the counterweight ring is used to increase the rotational inertia of the impeller.

6. The water turbine impeller structure of claim 1, wherein: The connecting part is provided with a chamfer on the edge, and the chamfer forms a groove for welding when the connecting parts are spliced.

7. The water turbine impeller structure according to claim 1, characterized by: The blade part is a double-cavity bucket, and the part where the blade part connects with the connecting part is a solid structure.

8. The water turbine impeller structure of claim 1, wherein: The impeller unit is produced by forging, casting or metal additive manufacturing.

9. A hydraulic turbine characterized by: The water turbine impeller structure of any one of claims 1-8 is adopted.

10. A method of manufacturing a water turbine impeller structure, characterized by, A method for assembling the water turbine impeller structure of any one of claims 1-8, comprising the following steps: 1) sequentially splicing a designed number of impeller units to make the protrusions and the grooves on the left and right inclined surfaces of the connecting parts sequentially match, and preliminarily forming a disc structure; 2) forming a groove between the adjacent two connecting parts in the preliminarily formed disc structure, and welding at the groove; preliminarily welding all the connecting parts together; 3) flattening the upper and lower surfaces of the preliminarily welded disc structure, installing the counterweight ring into the flattened annular stepped groove, and filling the annular stepped groove by using a surfacing process; 4) processing the center of the disc structure to form a hole structure for assembling a rotating shaft.

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