A runner mechanism for a water-turbine water-pump unit and a water-turbine water-pump unit

Abstract

This application discloses a runner mechanism for a water turbine pump unit and the water turbine pump unit itself. The runner mechanism includes an upper crown and a lower ring spaced apart, with multiple blades disposed between the upper crown and the lower ring. When the excitation frequency of the runner mechanism is less than its natural frequency, the arc dimensions of the first rounded structure and the second rounded structure are the first arc dimensions; when the excitation frequency of the runner mechanism is greater than its natural frequency, the arc dimensions of the first rounded structure and the second rounded structure are the second arc dimensions. The first arc dimension is larger than a preset arc dimension, and the difference between the first arc dimension and the preset arc dimension is between 10 mm and 40 mm. The second arc dimension is smaller than the preset arc dimension, and the difference between the second arc dimension and the preset arc dimension is between 0 mm and 20 mm. This effectively avoids the excitation frequency coinciding with the natural frequency, reduces the risk of resonance, and improves the frequency safety margin of the runner mechanism.

Description

Technical Field

[0001] This utility model belongs to the technical field of pumped storage equipment, specifically relating to a runner mechanism for a water turbine pump unit and the water turbine pump unit. Background Technology

[0002] Currently, some pumped storage power stations fail to adequately consider factors during the design phase. In obtaining the natural frequency of the turbine mechanism, unreasonable simplifications of the structure and neglect of wall effects and the influence of the added mass of the water on the natural frequency can easily lead to the hydraulic excitation frequency of the turbine structure being close to the natural frequency of the corresponding mode. This can easily cause resonance in the turbine mechanism. Once resonance occurs, it can easily lead to increased local deformation of the turbine mechanism, as well as increased stress concentration at the connection points between the blades and the upper crown, and between the blades and the lower ring. This increases the interference of local plastic deformation on the dynamic characteristics of the structure, thereby reducing the service life of the turbine mechanism. Utility Model Content

[0003] This application discloses a runner mechanism for a water turbine pump unit and the water turbine pump unit, aiming to solve the problems of increased local deformation, stress concentration, and reduced service life caused by resonance in the runner mechanism.

[0004] In a first aspect, to solve the above problems, embodiments of this application provide a runner mechanism for a water turbine pump unit, characterized in that the runner mechanism includes: An upper crown and a lower ring are spaced apart, and multiple blades are arranged between the upper crown and the lower ring; The connection between the blade and the upper crown forms a first rounded structure, and the connection between the blade and the lower ring forms a second rounded structure. When the excitation frequency of the rotating mechanism is less than its natural frequency, the arc dimensions of the first rounded structure and the second rounded structure are the first arc dimensions. When the excitation frequency of the rotating mechanism is greater than its natural frequency, the arc dimensions of the first rounded structure and the second rounded structure are the second arc dimensions. The first arc dimension is greater than a preset arc dimension, and the difference between the first arc dimension and the preset arc dimension is between 10 mm and 40 mm. The second arc dimension is less than the preset arc dimension, and the difference between the second arc dimension and the preset arc dimension is between 0 mm and 20 mm. The preset arc dimension is the arc dimensions of the first rounded structure and the second rounded structure when the rotating mechanism reaches the critical point of resonance.

[0005] In some embodiments, the upper crown includes at least a first region, and when the excitation frequency of the rotating mechanism is less than the natural frequency, the thickness of the first region of the upper crown is greater than a first preset thickness, and the difference between the thickness of the first region of the upper crown and the first preset thickness is between 2 mm and 10 mm. The lower ring includes at least a second region. When the excitation frequency of the rotating wheel mechanism is less than the natural frequency, the thickness of the second region of the lower ring is greater than a second preset thickness, and the difference between the thickness of the second region of the lower ring and the second preset thickness is between 2 mm and 10 mm. Wherein, the first preset thickness is the thickness of the first region of the upper crown when the wheel mechanism resonates, and the second preset thickness is the thickness of the second region of the lower ring when the wheel mechanism resonates.

[0006] In some embodiments, the upper crown includes at least a third region. When the excitation frequency of the rotating mechanism is greater than the natural frequency, the thickness of the third region of the upper crown is less than a first preset thickness, and the difference between the thickness of the third region of the upper crown and the first preset thickness is between 2 mm and 5 mm. The lower ring includes at least a fourth region. When the excitation frequency of the rotating wheel mechanism is greater than the natural frequency, the thickness of the fourth region of the lower ring is less than a second preset thickness, and the difference between the thickness of the fourth region of the lower ring and the second preset thickness is between 2 mm and 5 mm. Wherein, the first preset thickness is the thickness of the third region of the upper crown when the wheel mechanism resonates, and the second preset thickness is the thickness of the fourth region of the lower ring when the wheel mechanism resonates.

[0007] In some embodiments, when the thickness of the third region of the upper crown is less than or equal to 5% of the first preset thickness, the third region is provided with a first reinforcing structure.

[0008] In some embodiments, when the thickness of the fourth region of the lower ring is less than or 5% of the second preset thickness, the fourth region is provided with a second reinforcing structure.

[0009] In some embodiments, the first reinforcing structure and the second reinforcing structure are reinforcing ribs; The reinforcing ribs protrude from the surfaces of the upper crown and the lower ring away from the blade.

[0010] In some embodiments, the first region is located within a first non-vibration-sensitive area of ​​the upper crown, which is located in the region opposite the connection between the upper crown and the blade.

[0011] In some embodiments, the second region is located within the second non-vibration-sensitive area of ​​the lower ring, which is the area where the connection between the lower ring and the blade is located.

[0012] In some embodiments, the first region is located outside the first stepped sealing area provided on the upper crown, and the second region is located outside the second stepped sealing area provided on the lower ring.

[0013] Secondly, this application also provides a water turbine pump unit, which includes a volute, a seat ring, movable guide vanes, a tailrace pipe, a top cover, a bottom ring, and the runner mechanism described in any embodiment of the first aspect; The volute is connected to the seat ring, the movable guide vane is disposed between the seat ring and the impeller mechanism, the impeller mechanism is disposed between the top cover and the bottom ring, and the tailwater pipe is disposed on the side of the impeller mechanism away from the top cover.

[0014] According to the embodiments of this application, when the excitation frequency of the runner mechanism is less than the natural frequency, the arc dimensions of the first rounded structure and the second rounded structure are the first arc dimension, which is greater than the preset arc dimension, and the difference between the first arc dimension and the preset arc dimension is between 10 mm and 40 mm. The preset arc dimension is the arc dimension of the first rounded structure and the second rounded structure when the runner mechanism resonates. Therefore, when the excitation frequency of the runner mechanism is less than the natural frequency, the arc dimensions of the first rounded structure formed by the connection between the blade and the upper crown and the second rounded structure formed by the connection between the blade and the lower ring are increased compared to the arc dimension corresponding to the critical point of resonance of the runner mechanism. Based on the relationship between the excitation frequency and the number of runner blades, the number of active guide vanes and the unit rotation frequency, the cross-sectional moment of inertia (geometric stiffness) of the connection between the blade and the upper crown and the connection between the blade and the lower ring can be significantly improved, thereby enhancing the local bending and torsional resistance. At the same time, it reduces stress concentration at the connection between the blade and the upper crown, and at the connection between the blade and the lower ring, reduces the interference of local plastic deformation on the dynamic characteristics of the structure, suppresses the anti-phase vibration at the junction of the blade and the upper crown or the blade and the lower ring, increases the natural frequency of the runner mechanism, effectively avoids the excitation frequency from coinciding with the natural frequency, reduces the risk of resonance, and thus improves the frequency safety margin of the runner mechanism.

[0015] Conversely, since the excitation frequency of the wheel mechanism is greater than its natural frequency, the arc dimensions of the first rounded structure and the second rounded structure are the second arc dimensions, which are smaller than the preset arc dimensions. The difference between the second arc dimensions and the preset arc dimensions is between 0 mm and 20 mm. The preset arc dimensions are the arc dimensions of the first rounded structure and the second rounded structure when the wheel mechanism reaches the critical point of resonance. Therefore, without changing the structure of the wheel mechanism, by reducing the arc dimensions of the first rounded structure formed by the connection between the blade and the upper crown and the second rounded structure formed by the connection between the blade and the lower ring, the natural frequency of the wheel mechanism can be reduced, thereby improving the frequency safety margin of the wheel mechanism. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a partial structural schematic diagram of a turbine runner mechanism for a water turbine pump unit provided in an embodiment of this application; Figure 2 This is a schematic diagram of a water turbine pump unit provided in an embodiment of this application.

[0018] Explanation of reference numerals in the attached figures: 1: Runner mechanism; 11: Upper crown; 111: First reinforcing structure; 112: First non-vibration sensitive area; 113: First step sealing area; 12: Lower ring; 121: Second reinforcing structure; 122: Second non-vibration sensitive area; 123: Second step sealing area; 13: Blade; 14: First rounded structure; 15: Second rounded structure; 2: Volute; 3: Seat ring; 4: Movable guide vane; 5: Tailwater pipe; 6: Top cover; 7: Bottom ring. Detailed Implementation

[0019] The terms "first" and "second" in the specification and claims of this application may explicitly or implicitly include one or more of the features. In the description of this application, unless otherwise stated, "multiple" means two or more. Furthermore, "and / or" in the specification and claims indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.

[0020] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0021] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0022] Firstly, such as Figure 1 As shown in the figure, this application embodiment provides a turbine runner mechanism for a water turbine pump unit, the turbine runner mechanism including: An upper crown 11 and a lower ring 12 are spaced apart, and multiple blades 13 are arranged between the upper crown 11 and the lower ring 12.

[0023] The connection between the blade 13 and the upper crown 11 forms a first rounded structure 14, and the connection between the blade 13 and the lower ring 12 forms a second rounded structure 15.

[0024] When the excitation frequency of the rotating mechanism is less than the natural frequency, the arc size of the first rounded structure 14 and the second rounded structure 15 is the first arc size. When the excitation frequency of the rotating mechanism is greater than the natural frequency, the arc size of the first rounded structure 14 and the second rounded structure 15 is the second arc size. The first arc size is greater than the preset arc size, and the difference between the first arc size and the preset arc size is between 10 mm and 40 mm. The second arc size is less than the preset arc size, and the difference between the second arc size and the preset arc size is between 0 mm and 20 mm. The preset arc size is the arc size of the first rounded structure 14 and the second rounded structure 15 when the rotating mechanism reaches the critical point of resonance.

[0025] As can be seen from the above embodiments, in this application embodiment, since the excitation frequency of the rotating mechanism is less than the natural frequency, the arc size of the first rounded structure 14 and the second rounded structure 15 is the first arc size, which is larger than the preset arc size, and the difference between the first arc size and the preset arc size is between 10 mm and 40 mm. The preset arc size is the critical point at which the rotating mechanism resonates. Therefore, when the excitation frequency of the rotating mechanism is less than the natural frequency, the arc size of the first rounded structure 14 and the second rounded structure 15... The arc dimensions of the connection between blade 13 and upper crown 11 forming the first rounded structure 14 and the connection between blade 13 and lower ring 12 forming the second rounded structure 15 are increased compared to the arc dimensions corresponding to the critical point of resonance in the turbine mechanism. Based on the relationship between the excitation frequency and the number of turbine runner blades 13, the number of movable guide vanes, and the turbine rotation frequency, the moment of inertia (geometric stiffness) of the connection between blade 13 and upper crown 11, and the connection between blade 13 and lower ring 12 can be significantly increased, thereby enhancing local bending and torsional resistance. Simultaneously, stress concentration at the connection between blade 13 and upper crown 11, and the connection between blade 13 and lower ring 12 is reduced, minimizing the interference of local plastic deformation on the structural dynamics, suppressing anti-phase vibration at the junction of blade 13 and upper crown 11 or blade 13 and lower ring 12, increasing the natural frequency of the turbine mechanism, effectively avoiding the excitation frequency from coinciding with the natural frequency, reducing the risk of resonance, and thus improving the frequency safety margin of the turbine mechanism.

[0026] Conversely, since the excitation frequency of the wheel mechanism is greater than its natural frequency, the arc size of the first rounded structure 14 and the second rounded structure 15 is the second arc size, which is smaller than the preset arc size, and the difference between the second arc size and the preset arc size is between 0 mm and 20 mm. When the preset arc size is the critical point for resonance of the wheel mechanism, the arc size of the first rounded structure 14 and the second rounded structure 15 can be reduced without changing the structure of the wheel mechanism. This is because when the arc size of the connection between the blade 13 and the upper crown 11 is reduced to form the first rounded structure 14, and the connection between the blade 13 and the lower ring 12 is reduced to form the second rounded structure 15, the natural frequency of the wheel mechanism can be reduced, thereby improving the frequency safety margin of the wheel mechanism.

[0027] It should be noted that the formula for the natural frequency simulated by the impeller structure is as follows: Where f is the natural frequency, K is the stiffness of the wheel mechanism, and M is the mass of the wheel mechanism, it can be seen that the natural frequency f is directly proportional to the stiffness K of the wheel mechanism, and inversely proportional to the mass M of the wheel mechanism. Furthermore, based on the safety domain formula... Where y is the frequency safety margin under which the impeller mechanism does not resonate, f1 is the natural frequency in wet mode, and f2 is the hydraulic excitation frequency caused by dynamic-static interference. Since the condition for the impeller mechanism not to resonate is that the frequency safety margin must be greater than 10%, based on the simulation of the arc dimensions of the first rounded structure 14 formed by the connection between the upper crown 11 and the second rounded structure 15 formed by the connection between the blade 13 and the lower ring 12 (refer to Table 1), it can be seen that changing the arc dimensions will significantly change the stiffness of the impeller mechanism, but will not significantly change the mass of the impeller structure, thus significantly changing the natural frequency of the impeller mechanism, and consequently changing the safety margin of the impeller mechanism.

[0028] Table 1

[0029] In the above embodiment, the upper crown 11 is located at the top of the impeller mechanism and is directly connected to the main shaft through a flange structure, bearing the function of transmitting torque. It also provides support for the upper end of the blades 13, together forming the top boundary of the flow channel. The upper crown 11 is typically equipped with pressure-reducing holes or pressure-reducing devices (such as rotating pressure-reducing plates) to significantly reduce the load on the thrust bearing by balancing the water pressure above and below the impeller. The lower ring 12 is located at the lower end of the blades 13, connecting the blades 13 into an integral ring structure, greatly improving the rigidity and deformation resistance of the impeller mechanism, especially suitable for high-speed operation. The lower ring 12 and the upper crown 11 work together to form a complete flow channel profile, ensuring stable water flow. The lower leak-proof ring is fixed to the lower ring 12 to reduce downward leakage. Some designs add cooling water holes in the middle of the leak-proof ring to assist in heat dissipation.

[0030] In some embodiments, the upper crown 11 includes at least a first region. When the excitation frequency of the rotating mechanism is less than its natural frequency, the thickness of the first region of the upper crown 11 is greater than a first preset thickness, and the difference between the thickness of the first region of the upper crown 11 and the first preset thickness is between 2 mm and 10 mm. The lower ring 12 includes at least a second region. When the excitation frequency of the rotating mechanism is less than its natural frequency, the thickness of the second region of the lower ring 12 is greater than a second preset thickness, and the difference between the thickness of the second region of the lower ring 12 and the second preset thickness is between 2 mm and 10 mm. The first preset thickness is the thickness of the first region of the upper crown 11 when the rotating mechanism reaches the critical point of resonance, and the second preset thickness is the thickness of the second region of the lower ring 12 when the rotating mechanism reaches the critical point of resonance.

[0031] In this embodiment, since the upper crown 11 includes at least a first region, when the excitation frequency of the wheel mechanism is less than the natural frequency, the thickness of the first region of the upper crown 11 is greater than the first preset thickness, and the difference between the thickness of the first region of the upper crown 11 and the first preset thickness is between 2 mm and 10 mm. The first preset thickness is the thickness of the first region of the upper crown 11 when the wheel mechanism resonates. Therefore, thickening the surface of the upper crown 11, the main load-bearing structure of the wheel mechanism, will significantly improve the bending stiffness and torsional stiffness of the wheel mechanism. The increase in stiffness will directly lead to an increase in the natural frequency of the wheel. At the same time, thickening the upper and lower surfaces of the wheel can suppress the deformation of specific vibration modes, thereby changing the safety range of the wheel mechanism. Similarly, since the lower ring 12 includes at least a second region, when the excitation frequency of the wheel mechanism is less than the natural frequency, the thickness of the second region of the lower ring 12 is greater than the second preset thickness, and the difference between the thickness of the second region of the lower ring 12 and the second preset thickness is between 2 mm and 10 mm. The second preset thickness is the thickness of the second region of the lower ring 12 when the wheel mechanism resonates. Therefore, thickening the surface of the lower ring 12, the main load-bearing structure of the wheel mechanism, will significantly improve the bending stiffness and torsional stiffness of the wheel mechanism. The increase in stiffness will directly lead to an increase in the natural frequency of the wheel. At the same time, thickening the upper and lower surfaces of the wheel can suppress the deformation of specific vibration modes, thereby changing the safety range of the wheel mechanism. For example, by simulating the safety margin of the wheel mechanism under different thicknesses, the simulation data shown in Table 2 can be obtained. From Table 2, it can be seen that when the arc dimensions of the first rounded structure 14 and the second rounded structure 15 are the same, and when the excitation frequency of the wheel mechanism is less than the natural frequency, the thickness of the first region of the upper crown 11 is greater than the first preset thickness, so that the thickness of the first region of the lower ring 12 is greater than the second preset thickness, which can increase the safety margin of the wheel mechanism.

[0032] Table 2

[0033] It should be noted that when the excitation frequency of the wheel mechanism is less than the natural frequency, the arc dimensions of the first rounded structure 14 and the second rounded structure 15 can be the first arc dimension, or the thickness of the first region of the upper crown 11 can be greater than the first preset thickness, and the thickness of the first region of the lower ring 12 can be greater than the second preset thickness. Alternatively, the arc dimensions of the first rounded structure 14 and the second rounded structure 15 can be the first arc dimension, and the thickness of the first region of the upper crown 11 can be greater than the first preset thickness, and the thickness of the first region of the lower ring 12 can be greater than the second preset thickness. This application embodiment does not limit this.

[0034] In some embodiments, the upper crown 11 includes at least a third region. When the excitation frequency of the rotating mechanism is greater than its natural frequency, the thickness of the third region of the upper crown 11 is less than a first preset thickness, and the difference between the thickness of the third region of the upper crown 11 and the first preset thickness is between 2 mm and 5 mm. The lower ring 12 includes at least a fourth region. When the excitation frequency of the rotating mechanism is greater than its natural frequency, the thickness of the fourth region of the lower ring 12 is less than a second preset thickness, and the difference between the thickness of the fourth region of the lower ring 12 and the second preset thickness is between 2 mm and 5 mm. The first preset thickness is the thickness of the third region of the upper crown 11 when the rotating mechanism reaches the critical point of resonance, and the second preset thickness is the thickness of the fourth region of the lower ring 12 when the rotating mechanism reaches the critical point of resonance.

[0035] In this embodiment, since the upper crown 11 includes at least a third region, when the excitation frequency of the wheel mechanism is greater than the natural frequency, the thickness of the third region of the upper crown 11 is less than the first preset thickness, and the difference between the thickness of the third region of the upper crown 11 and the first preset thickness is between 2 mm and 5 mm. The first preset thickness is the thickness of the third region of the upper crown 11 when the wheel mechanism resonates. Therefore, the surface thinning treatment of the upper crown 11 of the main load-bearing structure of the wheel mechanism will directly weaken the moment of inertia of the section. The decrease in stiffness will directly lead to a decrease in the natural frequency of the wheel. At the same time, the thinning of the upper and lower surfaces of the wheel can suppress the deformation of specific vibration modes, thereby changing the safety range of the wheel mechanism.

[0036] Similarly, since the lower ring 12 includes at least a fourth region, when the excitation frequency of the wheel mechanism is greater than the natural frequency, the thickness of the fourth region of the lower ring 12 is less than the second preset thickness, and the difference between the thickness of the fourth region of the lower ring 12 and the second preset thickness is between 2 mm and 5 mm. The second preset thickness is the thickness of the fourth region of the lower ring 12 when the wheel mechanism resonates. Therefore, the surface thinning treatment of the lower ring 12, the main load-bearing structure of the wheel mechanism, will directly weaken the moment of inertia of the section. The decrease in stiffness will directly lead to a decrease in the natural frequency of the wheel. At the same time, the thinning of the upper and lower surfaces of the wheel can suppress the deformation of specific vibration modes, thereby changing the safety range of the wheel mechanism.

[0037] In some embodiments, when the thickness in the third region of the upper crown 11 is less than or equal to 5% of the first preset thickness, the third region is provided with a first reinforcing structure 111.

[0038] In this embodiment, the thinning of the third region of the upper crown 11 increases the structural flexibility of the wheel mechanism, causing vibration energy to concentrate in the weaker areas. Therefore, when the thickness of the third region of the upper crown 11 is less than or equal to 5% of the first preset thickness, the excitation frequency of the wheel mechanism decreases more rapidly. Thus, a first reinforcing structure 111 is provided in the third region to control the stiffness loss within 5%. Furthermore, the impact of thinning on the wet modal frequency needs to be evaluated through fluid-structure interaction simulation to ensure a frequency safety margin ≥ 10%.

[0039] In some embodiments, if the thickness of the fourth region of the lower ring 12 is less than 5% of the second preset thickness, the fourth region is provided with a second reinforcing structure 121.

[0040] Similarly, in this embodiment, the thinning of the fourth region of the lower ring 12 leads to an increase in the structural flexibility of the wheel mechanism, causing vibration energy to concentrate in the weaker areas. Therefore, when the thickness of the fourth region of the lower ring 12 is less than 5% of the second preset thickness, a second reinforcing structure 121 is provided in the fourth region to control the stiffness loss to within 5%.

[0041] In some embodiments, the first reinforcing structure 111 and the second reinforcing structure 121 are reinforcing ribs, which protrude from the surfaces of the upper crown 11 and the lower ring 12 away from the blade 13. In this way, the stiffness loss of the wheel mechanism is compensated by the reinforcing ribs.

[0042] In some embodiments, the first region is located within the first non-vibration sensitive area 112 of the upper crown 11, and the first non-vibration sensitive area 112 is located in the region where the upper crown 11 and the blade 13 are located opposite each other.

[0043] In this embodiment, since the first region is located within the first non-vibration sensitive area 112 of the upper crown 11, and the first non-vibration sensitive area 112 is located in the area where the connection between the upper crown 11 and the blade 13 is located, the impact of the thickening of the first region of the upper crown 11 on the connection between the upper crown 11 and the blade 13 can be reduced, while avoiding the impact of the thickening of the first region of the upper crown 11 on the vibration of the upper crown 11, and reducing the impact of the thickening of the first region of the upper crown 11 on the overall mass distribution of the wheel mechanism.

[0044] In some embodiments, the second region is located within the second non-vibration sensitive area 122 of the lower ring 12, which is the region where the connection between the lower ring 12 and the blade 13 is located.

[0045] In this embodiment, since the second region is located within the second non-vibration sensitive area 122 of the lower ring 12, which is the area where the connection between the lower ring 12 and the blade 13 is located, the thickening of the second region of the lower ring 12 can reduce the impact on the connection between the lower ring 12 and the blade 13, while avoiding the impact of the thickening of the second region of the lower ring 12 on the vibration of the lower ring 12, and reducing the impact of the thickening of the second region of the lower ring 12 on the overall mass distribution of the wheel mechanism.

[0046] In some embodiments, the first region is located outside the first step sealing area 113 provided on the upper crown 11, and the second region is located outside the second step sealing area 123 provided on the lower ring 12.

[0047] In this embodiment, since the impeller mechanism is a rotating component and the upper crown 11 and lower ring 12 are fixed components, a gap must be left between the rotating and fixed components to ensure the smooth rotation of the impeller. Water will flow through this gap to the outside of the unit, causing corrosion and short circuits. Therefore, a first-step sealing area 113 is provided on the upper crown 11 and a second-step sealing area is provided on the lower ring 12 to guide the water out of the unit. This ensures that the first area is located outside the first-step sealing area 113 on the upper crown 11, and the second area is located outside the second-step sealing area 123 on the lower ring 12, avoiding the influence of the first area on the first-step sealing area 113 and avoiding the impact of the thickened treatment of the second area on the function of the second-step sealing area 123.

[0048] As can be seen from the above embodiments, in this application embodiment, since the excitation frequency of the rotating mechanism is less than the natural frequency, the arc size of the first rounded structure 14 and the second rounded structure 15 is the first arc size, which is larger than the preset arc size, and the difference between the first arc size and the preset arc size is between 10 mm and 40 mm. The preset arc size is the critical point at which the rotating mechanism resonates. Therefore, when the excitation frequency of the rotating mechanism is less than the natural frequency, the arc size of the first rounded structure 14 and the second rounded structure 15... The arc dimensions of the connection between blade 13 and upper crown 11 forming the first rounded structure 14 and the connection between blade 13 and lower ring 12 forming the second rounded structure 15 are increased compared to the arc dimensions corresponding to the critical point of resonance in the turbine mechanism. Based on the relationship between the excitation frequency and the number of turbine runner blades 13, the number of movable guide vanes, and the turbine rotation frequency, the moment of inertia (geometric stiffness) of the connection between blade 13 and upper crown 11, and the connection between blade 13 and lower ring 12 can be significantly increased, thereby enhancing local bending and torsional resistance. Simultaneously, stress concentration at the connection between blade 13 and upper crown 11, and the connection between blade 13 and lower ring 12 is reduced, minimizing the interference of local plastic deformation on the structural dynamics, suppressing anti-phase vibration at the junction of blade 13 and upper crown 11 or blade 13 and lower ring 12, increasing the natural frequency of the turbine mechanism, effectively avoiding the excitation frequency from coinciding with the natural frequency, reducing the risk of resonance, and thus improving the frequency safety margin of the turbine mechanism.

[0049] Conversely, since the excitation frequency of the wheel mechanism is greater than its natural frequency, the arc size of the first rounded structure 14 and the second rounded structure 15 is the second arc size, which is smaller than the preset arc size, and the difference between the second arc size and the preset arc size is between 0 mm and 20 mm. When the preset arc size is the critical point for resonance of the wheel mechanism, the arc size of the first rounded structure 14 and the second rounded structure 15 can be reduced without changing the structure of the wheel mechanism. This is because when the arc size of the connection between the blade 13 and the upper crown 11 is reduced to form the first rounded structure 14, and the connection between the blade 13 and the lower ring 12 is reduced to form the second rounded structure 15, the natural frequency of the wheel mechanism can be reduced, thereby improving the frequency safety margin of the wheel mechanism.

[0050] Secondly, such as Figure 2 As shown, this application embodiment also provides a water turbine pump unit, which includes a volute 2, a seat ring 3, a movable guide vane 4, a tailrace pipe 5, a top cover 6, a bottom ring 7, and a turbine mechanism 1 according to any embodiment of the first aspect; the volute 2 is connected to the seat ring 3, the movable guide vane 4 is disposed between the seat ring 3 and the turbine mechanism 1, the turbine mechanism 1 is disposed between the top cover 6 and the bottom ring 7, and the tailrace pipe 5 is disposed on the side of the turbine mechanism 1 away from the top cover 6.

[0051] As can be seen from the above embodiments, since water flows into the impeller mechanism 1 through the movable guide vane 4, the movable guide vane 4 is stationary while the impeller mechanism 1 is rotating. The impeller mechanism 1 is affected by dynamic-static interference, and the pressure pulsation in the bladeless region between the movable guide vane 4 and the impeller mechanism 1 will be very intense, which may lead to resonance and damage to the impeller mechanism 1. Therefore, the impeller mechanism 1 for the water turbine pump unit provided in the above embodiments can significantly improve the moment of inertia (geometric stiffness) of the cross-section at the connection between the blade 13 and the upper crown 11, and the connection between the blade 13 and the lower ring 12, thereby enhancing local bending and torsional resistance. Simultaneously, it reduces stress concentration at the connection between the blade 13 and the upper crown 11, and the connection between the blade 13 and the lower ring 12, reducing the interference of local plastic deformation on the dynamic characteristics of the structure, suppressing the anti-phase vibration at the junction of the blade 13 and the upper crown 11 or the blade 13 and the lower ring 12, increasing the natural frequency of the impeller mechanism 1, effectively avoiding the excitation frequency from coinciding with the natural frequency, reducing the risk of resonance, and thus improving the frequency safety margin of the impeller mechanism 1.

[0052] The various embodiments in the specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0053] Although preferred embodiments of the present application have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of the embodiments of the present application.

[0054] Finally, it should be noted that in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or terminal device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or terminal device. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or terminal device that includes said element.

[0055] The present application has been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of the present application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of the present application. Therefore, the content of this specification should not be construed as a limitation of the present application.

Claims

1. A runner mechanism for a pump-turbine unit, characterized by, The rotating wheel mechanism includes: An upper crown (11) and a lower ring (12) are spaced apart, and multiple blades (13) are provided between the upper crown (11) and the lower ring (12). The connection between the blade (13) and the upper crown (11) forms a first rounded structure (14), and the connection between the blade (13) and the lower ring (12) forms a second rounded structure (15). When the excitation frequency of the rotating mechanism is less than the natural frequency, the arc size of the first rounded structure (14) and the second rounded structure (15) is the first arc size. When the excitation frequency of the rotating mechanism is greater than the natural frequency, the arc size of the first rounded structure (14) and the second rounded structure (15) is the second arc size. The first arc size is greater than the preset arc size, and the difference between the first arc size and the preset arc size is between 10 mm and 40 mm. The second arc size is less than the preset arc size, and the difference between the second arc size and the preset arc size is between 0 mm and 20 mm. The preset arc size is the arc size of the first rounded structure (14) and the second rounded structure (15) when the rotating mechanism reaches the critical point of resonance.

2. The runner mechanism for a pump-turbine unit according to claim 1, wherein The upper crown (11) includes at least a first region. When the excitation frequency of the rotating mechanism is less than the natural frequency, the thickness of the first region of the upper crown (11) is greater than a first preset thickness, and the difference between the thickness of the first region of the upper crown (11) and the first preset thickness is between 2 mm and 10 mm. The lower ring (12) includes at least a second region. When the excitation frequency of the wheel mechanism is less than the natural frequency, the thickness of the second region of the lower ring (12) is greater than the second preset thickness, and the difference between the thickness of the second region of the lower ring (12) and the second preset thickness is between 2 mm and 10 mm. Wherein, the first preset thickness is the thickness of the first region of the upper crown (11) when the wheel mechanism resonates, and the second preset thickness is the thickness of the second region of the lower ring (12) when the wheel mechanism resonates.

3. The runner mechanism for a pump-turbine unit according to claim 1, characterized by The upper crown (11) includes at least a third region. When the excitation frequency of the rotating mechanism is greater than the natural frequency, the thickness of the third region of the upper crown (11) is less than the first preset thickness, and the difference between the thickness of the third region of the upper crown (11) and the first preset thickness is between 2 mm and 5 mm. The lower ring (12) includes at least a fourth region. When the excitation frequency of the rotating wheel mechanism is greater than the natural frequency, the thickness of the fourth region of the lower ring (12) is less than the second preset thickness, and the difference between the thickness of the fourth region of the lower ring (12) and the second preset thickness is between 2 mm and 5 mm. Wherein, the first preset thickness is the thickness of the third region of the upper crown (11) when the wheel mechanism resonates, and the second preset thickness is the thickness of the fourth region of the lower ring (12) when the wheel mechanism resonates.

4. The runner mechanism for a pump-turbine unit according to claim 3, characterized in that When the thickness of the third region of the upper crown (11) is less than or equal to 5% of the first preset thickness, the third region is provided with a first reinforcing structure (111).

5. The runner mechanism for a pump-turbine unit according to claim 4, characterized in that When the thickness of the fourth region of the lower ring (12) is less than or 5% of the second preset thickness, the fourth region is provided with a second reinforcing structure (121).

6. The runner mechanism for a pump-turbine unit according to claim 5, characterized in that The first reinforcing structure (111) and the second reinforcing structure (121) are reinforcing ribs; The reinforcing ribs protrude from the surfaces of the upper crown (11) and the lower ring (12) away from the blade (13).

7. The runner mechanism for a pump-turbine unit according to claim 2, wherein The first region is located within the first non-vibration sensitive area (112) of the upper crown (11), and the first non-vibration sensitive area (112) is located in the area where the upper crown (11) and the blade (13) are located opposite each other.

8. The runner mechanism for a pump-turbine unit according to claim 2, wherein The second region is located within the second non-vibration sensitive area (122) of the lower ring (12), which is the area where the connection between the lower ring (12) and the blade (13) is located.

9. The runner mechanism for a pump-turbine unit according to claim 2, wherein The first region is located outside the first step sealing area (113) provided on the upper crown (11), and the second region is located outside the second step sealing area (123) provided on the lower ring (12).

10. A pump-turbine unit, characterized by The water turbine pump unit includes a volute (2), a seat ring (3), a movable guide vane (4), a tailpipe (5), a top cover (6), a bottom ring (7), and a runner mechanism (1) as described in any one of claims 1 to 9. The volute (2) is connected to the seat ring (3), the movable guide vane (4) is disposed between the seat ring (3) and the impeller mechanism (1), the impeller mechanism (1) is disposed between the top cover (6) and the bottom ring (7), and the tailwater pipe (5) is disposed on the side of the impeller mechanism (1) away from the top cover (6).

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