Mixed-flow water turbine runner with flow guide partition plate

Abstract

The invention provides a mixed-flow water turbine runner with flow guide partition plates, and relates to the technical field of water turbines. The water turbine runner comprises an upper crown, blades, a lower ring and a flow guide partition plate, the multiple blades are arranged in the circumferential direction at equal intervals, the upper crown is coaxially and fixedly connected to the tops of the multiple blades, and the lower ring is coaxially and fixedly connected to the peripheral sides of the bottoms of the multiple blades; the flow guide partition plates are fixedly connected to the middles of the blades in the water inlet direction and the water outlet direction, and inlet water and outlet water are divided into two paths through the flow guide partition plates between the adjacent blades. On the whole, the stability of water flow in the turbine runner can be effectively improved, abrasion is reduced, and the energy conversion efficiency of the turbine runner is effectively improved.

Description

Technical Field

[0001] The invention relates to the technical field of water turbines, in particular to a Francis turbine runner with a guide baffle. Background Art

[0002] Mixed-flow turbines are the most widely used type of turbine in power stations. The efficient and stable operation of the turbine runner when the incoming water flow rate varies greatly is an important issue in hydropower generation. During operation, the runner is impacted by solid particles such as sediment in the incoming flow for a long time and when it is operated to generate electricity under conditions that deviate from the rated operating conditions (generally 30%-75% of the rated operating conditions), the water flow inside the runner is unstable.

[0003] For example, the patent application publication number CN117685148A discloses an anti-abrasion turbine runner with diverter ribs, which mainly sets 3-5 diverter ribs on the runner blades. The diverter ribs slow down the sediment particles and prevent them from strongly impacting the runner blades, thus reducing the wear of the runner blades by the sediment. This patent cannot improve the internal backflow of the runner and the wear of the sediment at the outlet of the lower ring; however, the main working part of the turbine is the runner, which converts water energy into mechanical energy to generate electricity through the rotation of the runner. While the blade surface is worn by sediment, the internal water flow conditions will also affect the energy conversion.

[0004] Therefore, there is an urgent need for a mixed flow turbine runner with a guide baffle that can effectively improve the stability of the water flow in the turbine runner, reduce wear and effectively improve the energy conversion efficiency of the turbine runner. Summary of the invention

[0005] The purpose of the present invention is to provide a Francis turbine runner with a guide baffle, which solves the technical problem in the prior art that the water flow in the runner is uneven, blades are easily worn, and the energy conversion efficiency of the turbine runner is affected. The preferred technical solutions among the many technical solutions provided by the present invention can produce many technical effects as described below.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] The present invention provides a mixed flow turbine runner with a guide baffle, comprising an upper crown, blades, a lower ring and a guide baffle, wherein a plurality of blades are arranged at equal distances in the circumferential direction, the upper crown is coaxially fixedly connected to the tops of a plurality of blades, the lower ring is coaxially fixedly connected to the outer peripheral sides of the bottoms of a plurality of blades, the guide baffle is fixedly connected to the middle parts of a plurality of blades along the inlet and outlet directions, and the guide baffle is used to divide the inlet water and the outlet water between adjacent blades into two paths respectively.

[0008] Preferably, the guide baffle is arranged coaxially with the upper crown and the lower ring.

[0009] Preferably, the guide baffle is arranged as a trumpet-shaped structure, the large-diameter end of the guide baffle is arranged close to the water inlet direction, and the small-diameter end of the guide baffle is arranged close to the water outlet direction.

[0010] Preferably, the inner side of the guide baffle is set as a convex surface, and the outer side of the guide baffle is set as a concave surface.

[0011] Preferably, the blades are separated into upper blades and lower blades by the guide baffles, the upper blades are located on the convex surface, and the lower blades are located on the concave surface.

[0012] Preferably, it also includes:

[0013] A water inlet is provided between the outer circumference of the upper crown and the lower ring, and the large diameter end of the guide baffle, the upper blade and the water inlet end of the lower blade are respectively provided corresponding to the water inlet.

[0014] Preferably, it also includes:

[0015] A water outlet, the bottom of the lower ring is set as the water outlet, and the small diameter end of the guide baffle, the water outlet ends of the upper blade and the lower blade are respectively set corresponding to the water outlet.

[0016] Preferably, it also includes:

[0017] A pressure sensor is installed on the guide baffle.

[0018] Preferably, it also includes:

[0019] Air supply holes, a plurality of which are arranged on the side wall of the guide baffle and are connected to the air pump through the upper crown.

[0020] Preferably, the directions of the plurality of air replenishing holes are arranged to be inclined with respect to the direction of water flow.

[0021] In the technical solution provided by the present invention, all blades are fixedly connected to the guide baffles, which can effectively improve the strength of the blades and prevent the blades from being damaged during operation; the guide baffles are used between adjacent blades to divide the inlet and outlet water into two paths, on the one hand, under the action of centrifugation, the water is no longer too concentrated at the lower ring outlet, thereby reducing the flow rate at the lower ring outlet, improving the problem of silt wear at the outlet of the lower ring of the turbine runner, and on the other hand, the water flow can always completely fill the lower lobe runner to eliminate the upper ring backflow phenomenon, reduce the lower ring outflow speed, and the silt particles reduce their speed after hitting the guide baffles to reduce the possibility of hitting the wall of the runner blades. On the whole, the present application can effectively improve the stability of the water flow in the turbine runner, reduce wear and effectively improve the energy conversion efficiency of the turbine runner. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0023] Figure 1 It is a schematic diagram of the overall structure of the turbine runner of the present invention;

[0024] Figure 2 is a schematic cross-sectional view of a turbine runner of the present invention;

[0025] Figure 3 It is a cross-sectional schematic diagram of the guide baffle of the present invention.

[0026] In the figure, 1-upper crown; 2-upper blade; 3-lower ring; 4-guide baffle; 5-lower blade; 6-water inlet; 7-water outlet. DETAILED DESCRIPTION

[0027] To make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be described in detail below. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other implementation methods obtained by ordinary technicians in this field without creative work belong to the scope of protection of the present invention.

[0028] refer to Figure 1-3 A specific embodiment of the present invention provides a mixed flow turbine runner with a guide baffle, comprising an upper crown 1, blades, a lower ring 3 and a guide baffle 4, wherein a plurality of blades are arranged at equal distances in the circumferential direction, the upper crown 1 is coaxially fixedly connected to the tops of a plurality of blades, the lower ring 3 is coaxially fixedly connected to the outer peripheral sides of the bottoms of a plurality of blades, the guide baffle 4 is fixedly connected to the middle parts of a plurality of blades along the inlet and outlet directions, and the guide baffle 4 is used between adjacent blades to divide the inlet and outlet water into two paths respectively.

[0029] When the existing mixed-flow turbine is running to generate electricity, the water flow inside the runner is unstable. The unstable flow inside the turbine runner is mainly manifested in: the solid particles such as mud and sand in the water flow cause impact wear on the runner, and the water flow is not fixed, the upper crown is prone to backflow, and the flow rate at the outlet of the lower ring is large and uneven. Long-term operation of power generation will intensify the mud and sand wear phenomenon of the runner, reach the fatigue limit stress of the limited life of the runner, cause the runner material to fail, and cause different forms of damage to the blades such as cracks and fractures, reduce the service life of the runner, and affect the energy conversion efficiency of the turbine runner. In the present application, all blades are fixedly connected to the guide baffle 4, which can effectively improve the strength of the blades and prevent the blades from being damaged during operation; the guide baffle 4 is used between adjacent blades to divide the incoming water and the outgoing water into two paths, respectively. On the one hand, under the action of centrifugation, the water is no longer too concentrated at the outlet position of the lower ring 3, thereby reducing the outlet flow rate of the lower ring 3, and improving the problem of silt wear at the outlet of the lower ring of the turbine runner. On the other hand, the water flow can always completely fill the lower lobe runner to eliminate the upper ring backflow phenomenon, reduce the outflow speed of the lower ring 3, and the silt particles reduce their speed after hitting the guide baffle 4 to reduce the possibility of hitting the wall of the runner blade. On the whole, the present application can effectively improve the stability of the water flow in the turbine runner, reduce wear and effectively improve the energy conversion efficiency of the turbine runner.

[0030] To further optimize the solution, the guide baffle 4 is arranged coaxially with the upper crown 1 and the lower ring 3; the guide baffle 4 is arranged as a trumpet-shaped structure, the large diameter end of the guide baffle 4 is arranged close to the water inlet direction, and the small diameter end of the guide baffle 4 is arranged close to the water outlet direction; the inner side of the guide baffle 4 is arranged as a convex surface, and the outer side of the guide baffle 4 is arranged as a concave surface.

[0031] With this arrangement, the guide baffle 4 has a certain guiding effect on the water flow, dividing the water flow into two downward paths, and no longer causing the water flow to be overly concentrated at the outlet position of the lower ring 3, thereby reducing the outflow velocity of the lower ring 3. The water flow flows downstream along the axial direction, and the sediment particles reduce their speed after hitting the guide baffle 4, reducing the possibility of hitting the wall of the runner blades.

[0032] The guide baffle 4 is welded and polished to the runner blades, and the material used for the guide baffle 4 is consistent with the blade material, i.e., high-strength stainless steel. The present invention provides a guide baffle 4, and the overall structure is simple and easy to replace. The technology is reliable in actual power station project implementation, and the application prospects are broad. It can generate huge economic benefits, improve the utilization rate of water resources, improve the efficiency of hydropower generation, and ensure the stability of the power grid.

[0033] According to a further optimized solution, the blades are separated into upper blades 2 and lower blades 5 by guide baffles 4, wherein the upper blades 2 are located on the convex surface and the lower blades 5 are located on the concave surface.

[0034] When generating electricity under different working conditions, the high-speed rotation of the impeller will cause unstable flow of water inside the impeller, affecting the operating efficiency of the impeller. Under the action of the guide baffle 4, the turbulent water flow is blocked from continuing to extend downward, so the flow state below the guide baffle 4 is smoother and more stable than the flow state above, eliminating the potential safety hazard to the power plant building caused by the unstable operation of the impeller due to the turbulent water flow; when the operation deviates from the optimal design conditions, vortices and other undesirable conditions that deviate from the mainstream will appear between the two blades, thereby reducing the efficiency of the impeller. The guide baffle 4 divides the impeller into two, eliminates most of the undesirable flow states at the top, optimizes the flow state of the water flow below the guide baffle 4, and makes the water flow below the guide baffle 4 fully utilize the water flow to drive the impeller to rotate and generate mechanical energy under any operating condition, eliminates the impeller vortex, improves stable power generation, and reduces the harm caused by the water flow.

[0035] Further optimization plans also include:

[0036] A water inlet 6 is arranged between the outer circumference of the upper crown 1 and the lower ring 3 , and the large diameter end of the guide baffle 4 , the water inlet ends of the upper blade 2 and the lower blade 5 are arranged corresponding to the water inlet 6 .

[0037] Further optimization plans also include:

[0038] The water outlet 7 , the bottom of the lower ring 3 is set as the water outlet 7 , and the small diameter end of the guide baffle 4 , the water outlet ends of the upper blade 2 and the lower blade 5 are respectively set corresponding to the water outlet 7 .

[0039] When the water flows into the water inlet 6 of the runner, it first impacts the water inlet end of the runner blades; the water flows into the runner in a radial direction and enters from the outer periphery of the runner in a direction approximately perpendicular to the rotation axis of the runner. Due to the presence of the guide baffle 4, the water flow can always completely fill the lower lobe of the runner, effectively eliminating the backflow phenomenon of the upper crown 1, preventing the water flow from excessive diffusion or turbulence in the circumferential direction, so that the water flow can flow along the designed path inside the runner, ensuring the effective conversion of water flow energy. After the water flows into the runner, it is easy to form blade channel vortices of different sizes between two adjacent blades, resulting in turbulent flow inside the runner. The use of the guide baffle 4 can effectively block the downward extension of the vortex and break the vortex, reduce the occurrence of internal separation from the mainstream, and improve the flow state inside the runner. The water flows along the surface of the blade in the blade flow channel of the runner, and the pressure is higher on the pressure surface of the blade, while the pressure is relatively low on the suction surface of the blade. This pressure difference enables the water flow to adhere tightly to the surface of the blade and drive the runner to rotate. In this process, the energy of the water flow is transferred to the runner, driving the runner to rotate and realizing energy conversion. At the runner outlet 7, the water flow direction changes to axial direction and flows out of the runner from the bottom of the runner.

[0040] Further optimization plans also include:

[0041] A pressure sensor is installed on the guide baffle 4;

[0042] Air replenishing holes, a plurality of air replenishing holes are provided on the side wall of the guide baffle 4, and are connected with the air pump through the upper crown 1; the orientation of the plurality of air replenishing holes is inclined with respect to the direction of the water flow.

[0043] As the impeller rotates (the centrifugal force generated by the rotation of the impeller), the water flow is no longer too concentrated at the outlet of the lower ring due to the guiding effect of the guide baffle 4, thereby reducing the outflow velocity of the lower ring. The water flows downstream along the axial direction. After hitting the guide baffle, the sediment particles reduce their speed to reduce the possibility of hitting the wall of the impeller blades. In addition, air replenishment holes are set on the surface of the guide baffle 4 to form an air film layer on the surface of the guide baffle 4 to protect the guide baffle and reduce the wear of the impeller. A pressure sensor is set on the guide baffle 4 to monitor the water flow inside the impeller in real time and control the air replenishment amount.

[0044] According to a further optimization scheme, the wall thickness of the guide baffle 4 is 0.8-1 times the thickness of the blade.

[0045] It should be noted that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", etc. used herein to indicate the orientation or position relationship is based on the orientation or position relationship shown in the drawings, and is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second", "third", etc. are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0046] In the description of this article, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0047] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A Francis turbine runner with a guide baffle, characterized in that: The invention comprises an upper crown (1), blades, a lower ring (3) and a guide baffle (4), wherein a plurality of blades are arranged at equal distances in the circumferential direction, the upper crown (1) is coaxially fixedly connected to the top of a plurality of blades, the lower ring (3) is coaxially fixedly connected to the outer peripheral side of the bottom of a plurality of blades, the guide baffle (4) is fixedly connected to the middle of a plurality of blades along the water inlet and outlet directions, and the guide baffle (4) is used to separate the inlet water and the outlet water between adjacent blades into two paths.

2. The Francis turbine runner with a guide baffle according to claim 1, characterized in that: The guide baffle (4) is coaxially arranged with the upper crown (1) and the lower ring (3).

3. The Francis turbine runner with a guide baffle according to claim 1, characterized in that: The guide baffle (4) is arranged as a trumpet-shaped structure, the large-diameter end of the guide baffle (4) is arranged close to the water inlet direction, and the small-diameter end of the guide baffle (4) is arranged close to the water outlet direction.

4. The Francis turbine runner with a guide baffle according to claim 3, characterized in that: The inner side of the guide baffle (4) is arranged as a convex surface, and the outer side of the guide baffle (4) is arranged as a concave surface.

5. The Francis turbine runner with guide baffle according to claim 4, characterized in that: The blades are divided into upper blades (2) and lower blades (5) by the guide baffles (4); the upper blades (2) are located on the convex surface, and the lower blades (5) are located on the concave surface.

6. The Francis turbine runner with guide baffle according to claim 5, characterized in that: Also includes: A water inlet (6) is provided between the outer circumference of the upper crown (1) and the lower ring (3), and the large diameter end of the guide baffle (4), the upper blade (2) and the water inlet end of the lower blade (5) are respectively provided corresponding to the water inlet (6).

7. The Francis turbine runner with a guide baffle according to claim 3, characterized in that: Also includes: A water outlet (7), wherein the bottom of the lower ring (3) is arranged as the water outlet (7), and the small diameter end of the guide baffle (4), the water outlet ends of the upper blade (2) and the lower blade (5) are arranged corresponding to the water outlet (7).

8. The Francis turbine runner with a guide baffle according to claim 1, characterized in that: Also includes: A pressure sensor is installed on the guide baffle (4).

9. The Francis turbine runner with a guide baffle according to claim 1, characterized in that: Also includes: Air supply holes, a plurality of which are arranged on the side wall of the guide baffle (4) and are connected to the air pump through the upper crown (1).

10. The Francis turbine runner with guide baffles according to claim 9, characterized in that: The directions of the plurality of air replenishing holes are arranged to be inclined with respect to the water flow direction.

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