Mixed-flow water turbine runner blade with adjustable leading edge aileron and runner

Abstract

The utility model belongs to the technical field of fluid mechanical engineering equipment, and particularly relates to a mixed-flow water turbine runner blade with an adjustable leading edge aileron and a runner. The runner blade consists of a runner blade body, a leading edge aileron, an angle adjusting device and a crank arm, the front edge aileron is connected to the front edge of the runner blade body; and the angle adjusting device is connected with the leading edge aileron through a crank arm. According to the water turbine runner formed by the multiple mixed-flow water turbine blades with the leading edge ailerons, under the small-flow working condition, by changing the angles of the leading edge ailerons, the trend that main flow in an outlet area deviates from a suction surface and turns to one side of a pressure surface to flow is weakened, the main flow speed of the suction surface is increased, and the speed distribution of a runner outlet is more uniform; the mixing of low-speed fluid at the bottom layer of the head boundary layer of the suction surface of the blade and high-energy fluid in mainstream is enhanced; the energy of the bottom layer of the boundary layer is enhanced, the reverse pressure gradient is reduced, the flow separation phenomenon is delayed, and separation vortexes in a runner channel under the small-flow working condition are reduced.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the technical field of fluid machinery engineering equipment, and particularly relates to a Francis turbine runner blade with adjustable leading edge flap. BACKGROUND

[0002] The Francis turbine is a kind of reaction turbine, and its flow passage is mainly composed of a spiral case, guide vanes, a runner, a draft tube and the like, water flows in radially and flows out axially. The Francis turbine has compact structure and high efficiency, and can adapt to a very high water head range, so it is widely used in the power system at present.

[0003] In order to realize the functions of network frequency regulation and grid load regulation, the Francis turbine will experience rapid and frequent load changes, start-stop processes and the like, so that the hydroelectric generating set will frequently deviate from the rated operating condition to regulate the grid parameters. Due to the fact that the internal flow field of the unit cannot guarantee the best flow conditions, phenomena such as impact, flow separation, cavitation, secondary flow and the like will occur, including the backflow at the runner inlet and the jet-wake structure and flow separation in the runner flow passage, which affect the flow field distribution of the Francis turbine and are the main reasons for the low efficiency of the Francis turbine. The runner blade not only guides the water flow, but also bears alternating stress load, so it is the most important part of the research on the internal flow field of the Francis turbine and the optimization of the Francis turbine design, and the structure of the runner blade has an important influence on the hydraulic performance of the Francis turbine. SUMMARY

[0004] The utility model provides a kind of Francis turbine runner blade with adjustable leading edge flap, and its purpose is to provide a kind of Francis turbine blade that can improve the performance of Francis turbine, improve the efficiency of Francis turbine in full operating condition range, expand operating range.

[0005] To achieve the above object, the utility model adopts the technical scheme that

[0006] A kind of Francis turbine runner blade with adjustable leading edge flap, at least including runner blade body, further including leading edge flap, angle adjusting device and bell crank;The leading edge flap is arranged at the leading edge water flow inlet of runner blade body, and there is gap between the leading edge of runner blade body and the leading edge flap;The angle adjusting device is connected with the leading edge flap;One end of the bell crank is connected with the angle adjusting device.

[0007] The flap head of the leading edge flap is provided with a section of arrayed wave structure;Wave extends in the direction of the longitudinal direction of the leading edge flap and is parallel to the longitudinal axis direction of the leading edge flap;The bottom surface of the leading edge flap is provided with a shaft;The shaft and the leading edge flap are integrated structure.

[0008] The chord length L1 of the leading edge flap is 20-25% of the runner blade body chord length.

[0009] The thickness D of the leading edge flap is equal to the runner blade body thickness.

[0010] The deflection angle of the leading edge flap ranges from 0 to 20°, and the end close to the runner blade body leading edge matches the shape of the runner blade body leading edge.

[0011] The length L2 of the leading edge flap head is twice the runner blade body thickness, and the gap between the leading edge flap and the runner blade body is 1 / 10 of the runner blade body width.

[0012] The angle adjusting device comprises a vane arm, a half key and an end cover, one end of the vane arm is connected with the end cover through the half key, the other end of the vane arm is connected with a crank arm, and the end cover is fixedly connected with the leading edge flap.

[0013] The end cover comprises a cover body and a rotating shaft, and the rotating shaft is arranged at the center of the cover body and fixedly connected with the leading edge flap.

[0014] The crank arm comprises two rectangular columnar rods and a rotating sleeve, the two columnar rods are connected through the rotating sleeve, the end of one columnar rod is provided with a screw hole, and the end of the other columnar rod away from the screw hole is provided with a shaft hole.

[0015] The mixed-flow water turbine runner comprises a main shaft and a rear cover plate, the main shaft is arranged at the center of the rear cover plate, a plurality of mixed-flow water turbine runner blades with adjustable leading edge flaps are arranged on the rear cover plate, each leading edge flap and an angle adjusting device are rotatably connected to the rear cover plate, the other end of the crank arm is connected with the main shaft, and a plurality of runner blade bodies are arranged on the rear cover plate in a spiral shape with the main shaft as the center.

[0016] Advantages:

[0017] (1) The utility model at least includes runner blade body, still includes leading edge flap, angle adjusting device and crank arm, through the leading edge flap arranged at the leading edge entrance of runner blade body, under the small flow condition, the trend that the main flow deviates from the suction surface and turns to the pressure surface side of the outlet area is weakened by changing the rotation angle of the leading edge flap, the main flow velocity of the suction surface is increased, and the runner outlet velocity distribution is more uniform.

[0018] (2) The utility model strengthens the mixing of the low-speed fluid in the boundary layer bottom layer of the blade suction surface head and the high-energy fluid in the main flow through the arrangement of the leading edge flap, strengthens the energy of the boundary layer bottom layer, thereby reduces the adverse pressure gradient, delays the flow separation phenomenon, and significantly reduces the separation vortex in the runner flow passage under the small flow condition.

[0019] The above description is only a summary of the technical scheme of the present application, in order to more clearly understand the technical means of the present application, and can be implemented according to the content of the specification, the following is the preferred embodiment of the present application and the detailed description of the drawings as follows. BRIEF DESCRIPTION OF DRAWINGS

[0020] In order to more clearly illustrate the technical scheme in the embodiments of the present application or the prior art, the drawings needed in the embodiments will be briefly introduced as follows. Obviously, the drawings described below are only some embodiments of the present application, and for those skilled in the art, other drawings can be obtained without creative labor on the basis of these drawings.

[0021] Figure 1 The structure of the present application is shown in the figure.

[0022] Figure 2 The structure of the present application is shown in the figure.

[0023] Figure 3 The control structure of the present application is shown in the figure.

[0024] Figure 4 The cross section of the overall control of the present application is shown in the figure.

[0025] Figure 5 is Figure 2 The front edge flap is shown in the figure.

[0026] In the figure: 1, back cover plate; 2, runner blade body; 3, front edge flap; 4, flap head; 5, angle adjusting device; 5-1, guide vane arm; 5-2, half key; 5-3, end cover; 5-4, rotating shaft; 6, crank arm; 7, screw hole; 8, shaft; 9, shaft hole; 10, rotating sleeve; 11, main shaft; 12, wave. DETAILED DESCRIPTION

[0027] The technical scheme in the embodiments of the present application will be described clearly and completely in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only some embodiments of the present application, not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0028] Embodiment one:

[0029] According to Figures 1-5The runner blade of the Francis turbine with adjustable leading edge flap includes a runner blade body 2, a leading edge flap 3, an angle adjusting device 5 and a toggle lever 6. The leading edge flap 3 is arranged at the front edge water inlet of the runner blade body 2 and has a gap with the front edge of the runner blade body 2. The angle adjusting device 5 is connected with the leading edge flap 3. One end of the toggle lever 6 is connected with the angle adjusting device 5.

[0030] In actual use, a plurality of runner blade bodies 2 are arranged in a spiral shape around the main shaft 11 on the back cover plate 1. The main shaft 11 is arranged at the center of the back cover plate 1. The toggle lever 6, the angle adjusting device 5 and the leading edge flap 3 are arranged in one-to-one correspondence with the runner blade body 2. The leading edge flap 3 is arranged along the radial direction of the back cover plate 1. The angle adjusting device 5 and the leading edge flap 3 are rotatably connected to the back cover plate 1. The back cover plate 1 is a prior art. One end of the toggle lever 6 is connected with the angle adjusting device 5. The other end of the toggle lever 6 is connected with the main shaft 11 in the turbine runner. When the main shaft 11 rotates, the toggle lever 6 is driven to move, thereby driving the angle adjusting device 5 connected therewith to rotate. The rotation of the angle adjusting device 5 drives the adjustment of the angle of the leading edge flap 3. A plurality of angle adjusting devices 5 are connected to the main shaft 11 through corresponding toggle levers 6, thereby realizing the coordinated action of a plurality of leading edge flaps 3, and optimizing the performance of the turbine in all working conditions.

[0031] In operation, fluid enters the flow channel on the back cover plate 1 along the runner blade body 2 and rotates clockwise along the runner blade body 2. In a small flow condition, when the fluid passes through the deflectable leading edge flap 3, it first passes through the flap head 4, thereby strengthening the stability of the flow state to some extent, weakening the tendency of the main flow in the water flow outlet area (the area near the edge of the runner blade body 2 where the leading edge flap 3 is located) to deviate from the suction surface and turn to the pressure surface side, making the outlet velocity distribution of the runner more uniform, strengthening the mixing of the low-speed fluid in the bottom boundary layer of the blade suction surface head and the high-energy fluid in the main flow, strengthening the energy of the bottom boundary layer, thereby reducing the adverse pressure gradient and delaying the flow separation phenomenon. This makes the separation vortex in the runner flow channel significantly reduced in the small flow condition.

[0032] In the technical solution, the runner blade body 2 and the leading edge flap 3 adopt a segmented combined structure. When the leading edge flap 3 is worn or cavitated, it can be directly disassembled and replaced without the need to replace the runner blade body 2 as a whole. The angle of the leading edge flap 3 can be easily rotated for different working conditions (such as the wet season / dry season).

[0033] Further, in some embodiments, the flap head 4 of the leading edge flap 3 is provided with an array of wave-shaped structures. The wave 12 extends in the longitudinal direction of the leading edge flap 3 and is parallel to the longitudinal axis direction of the leading edge flap 3 (for example, the wave 12 extends in the direction of the arrow A in FIG. 4). Figure 5The bottom surface of the leading edge flap 3 is provided with a shaft 8; the shaft 8 is in an integrated structure with the leading edge flap 3. In actual use, the shaft 8 is fixedly connected to the rotating shaft 5-4 in the angle adjusting device 5, and when the rotating shaft 5-4 rotates, the leading edge flap 3 is deflected in angle. The shaft 8 in the embodiment is arranged at the middle part of the leading edge flap 3, and when the leading edge flap 3 rotates, the shaft 8 serves as the axis of the leading edge flap 3. Through synergistic dissipation, flow separation is inhibited, the turbulence intensity is reduced, the energy loss is reduced and the efficiency is improved, the flow stability is enhanced and the structural stress distribution is optimized; the dynamic pressure field is reconstructed to disperse the cavity collapse energy, thereby prolonging the service life of the equipment.

[0034] In some embodiments, the chord length L1 of the leading edge flap 3 is 20%-25% of the chord length of the runner blade body 2. The chord length of the leading edge flap 3 adopts the technical solution, which can avoid excessive occupation of the flow passage section, reduce the local blocking effect when the water flow passes through, thereby reducing the turbulence and vortex generation, and maintaining the smoothness of the water flow; on the other hand, the rotational inertia of the leading edge flap 3 adopting the technical solution is smaller, and it responds faster under the driving of the angle adjusting device 5, which is convenient for quickly adapting to the changes of flow or water head, and improves the dynamic adjustment performance of the water turbine.

[0035] In some embodiments, the thickness D of the leading edge flap 3 is equal to the thickness of the runner blade body 2. The adoption of the technical solution can make the stress distribution uniform, the material rigidity of the connection region of the leading edge flap 3 and the runner blade body 2 is similar, avoid local stress concentration caused by sudden thickness change, thereby reducing the risk of fatigue cracking and prolonging the service life; on the other hand, the synchronous deformation resistance: under the impact of high-speed water flow, the leading edge flap 3 and the runner blade body 2 synchronously bear pressure, and the equal thickness can ensure that the bending deformation amounts of the two are similar, preventing structural interference or sealing failure caused by rigidity difference.

[0036] In some embodiments, the deflection angle of the leading edge flap 3 is 0-20°; and the end close to the leading edge of the runner blade body 2 is matched with the shape of the leading edge of the runner blade body 2. The adoption of the technical solution matches the boundary layer and the turbulence scale, optimizes the energy distribution; avoids resonance and widens the working condition adaptability, improves the efficiency while taking into account the service life and reliability, and is suitable for extreme fluid mechanical working conditions.

[0037] In some embodiments, the length L2 of the flap head 4 in the leading edge flap 3 is twice the thickness of the runner blade body 2. The design of this technical solution, on the one hand, makes the flow state smooth: the elongated microstructure head forms a more gentle streamline transition, reduces the impact and turbulence generated when the water flow enters the blade, suppresses flow separation, and reduces energy loss. On the other hand, it suppresses vortex generation: the extension length of twice the thickness can effectively guide the water flow to stably adhere along the blade surface, avoiding the phenomenon of local vortex or backflow caused by insufficient flow rate under low flow conditions. The flap head 4 in this embodiment is designed as an array of waves 12, which suppresses the expansion of the low pressure area, and at the same time, by suppressing the backflow vortex shedding, the vibration amplitude of the runner blade body 2 is reduced, and the peak value of the cavitation volume fraction on the surface of the runner blade body 2 is reduced.

[0038] In some embodiments, the gap between the leading edge flap 3 and the runner blade body 2 is 1 / 10 of the width of the runner blade body 2. The gap structure between the leading edge flap 3 and the runner blade body 2 in the technical solution destroys the coherence of large-scale vortices, reduces the amplitude of pressure pulsation, promotes the uniformization of velocity distribution, and reduces the turbulence intensity in the main flow area.

[0039] In some embodiments, the angle adjusting device 5 includes a vane arm 5-1, a half key 5-2, and an end cover 5-3; one end of the vane arm 5-1 is connected to the end cover 5-3 through the half key 5-2, the other end of the vane arm 5-1 is connected to the toggle arm 6; and the end cover 5-3 is fixedly connected to the leading edge flap 3.

[0040] Further, the end cover 5-3 includes a cover body and a rotating shaft 5-4; the rotating shaft 5-4 is arranged at the center of the cover body; and the rotating shaft 5-4 is fixedly connected to the leading edge flap 3.

[0041] In actual use, one end of the vane arm 5-1 is connected to the toggle arm 6, the other end is connected to the rotating shaft 5-4, and the shaft rod 8 in the leading edge flap 3 is connected to the rotating shaft 5-4. When the main shaft 11 rotates, the vane arm 5-1 is driven to rotate through the toggle arm 6, thereby driving the rotating shaft 5-4 to rotate and driving the leading edge flap 3 to rotate. The toggle arm 6 plays a role in transmitting torque.

[0042] In some embodiments, the toggle arm 6 includes two rectangular columnar rods and a rotating sleeve 10; the two columnar rods are connected through the rotating sleeve 10; one end of one of the columnar rods is provided with a threaded hole 7, and the other end of the other columnar rod away from the threaded hole 7 is provided with a shaft rod hole 9. In specific applications, the threaded hole 7 is used for connecting with the vane arm 5-1, and the shaft rod hole 9 is used for connecting with the main shaft 11 in the runner.

[0043] Embodiment two:

[0044] Reference Figures 1-5The Francis turbine runner comprises a main shaft 11 and a back cover plate 1, the main shaft 11 is arranged in the center of the back cover plate 1, a plurality of Francis turbine runner blades with adjustable leading edge flaps 3, each of the leading edge flaps 3 and an angle adjusting device 5 are rotatably connected to the back cover plate 1, the other end of a crank arm 6 is connected to the main shaft 11, and a plurality of runner blade bodies 2 are arranged in a spiral shape on the back cover plate 1 with the main shaft 11 as the center.

[0045] In actual use, in order to ensure the service life of the Francis turbine runner, a sealing ring is arranged on the inner wall of the shaft hole 9, an anti-wear plate is arranged between the back cover plate 1 and the crank arm 6, and the anti-wear plate is fixed on the back cover plate 1 by means of a nut. In the embodiment, the anti-wear plate is made of hard alloy, such as tungsten carbide WC or cobalt-based hard alloy.

[0046] In specific application, fluid enters the flow channel on the back cover plate 1 along the runner blade body 2, rotates clockwise along the runner blade body 2, and when the fluid passes through the deflectable angle leading edge flap 3, the stability of the flow state is enhanced to a certain extent after passing through the flap head 4, the tendency of the main flow in the outlet area to deviate from the suction surface and turn to the pressure surface side is weakened, the outlet velocity distribution of the runner is more uniform, the mixing of the low-speed fluid in the boundary layer bottom of the blade suction surface head and the high-energy fluid in the main flow is enhanced, the energy of the boundary layer bottom is enhanced, thereby reducing the adverse pressure gradient and delaying the flow separation phenomenon. The separation vortex in the runner flow channel under small flow conditions is significantly reduced.

[0047] In the case of no conflict, the person skilled in the art can combine the technical features related in the above examples according to the actual situation to achieve the corresponding technical effects. For various combinations, specific descriptions are not repeated here.

[0048] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present application are only used to explain the relative positional relationship, movement condition, etc. between the components in a certain specific posture (as shown in the drawings), and if the specific posture changes, the directional indications also change accordingly.

[0049] In addition, the description of "first", "second" and the like in the present application is only for the purpose of description, and cannot be understood as indicating or implying the relative importance of the indicated technical features or implicitly indicating the number of the indicated technical features. Therefore, the features limited by "first" and "second" can explicitly or implicitly include at least one of the features.

[0050] The above are only preferred embodiments of the present application, and the present application will not be limited to these embodiments shown in the present document, but will be subject to the widest scope consistent with the principles and novel characteristics disclosed in the present document. Any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present application still belong to the scope of the technical scheme of the present application.

Claims

1. A Francis turbine runner blade with an adjustable leading edge flap, comprising at least a runner blade body (2), characterized in that: It also comprises a leading edge flap (3), an angle adjusting device (5) and a crank arm (6); the leading edge flap (3) is arranged at the front edge water inlet of the runner blade body (2) and has a gap with the front edge of the runner blade body (2); the angle adjusting device (5) is connected with the leading edge flap (3); one end of the crank arm (6) is connected with the angle adjusting device (5).

2. A Francis turbine runner blade with an adjustable nose flap as defined in claim 1, characterized in that: The flap head (4) of the leading edge flap (3) is provided with a section of arrayed wave structure; the extension direction of the wave (12) along the longitudinal direction of the leading edge flap (3) is parallel to the longitudinal axis direction of the leading edge flap (3); the bottom surface of the leading edge flap (3) is provided with a shaft (8); the shaft (8) and the leading edge flap (3) are an integral structure.

3. A Francis turbine runner blade with an adjustable nose flap as defined in claim 1, characterized in that: The chord length L1 of the leading edge flap (3) is 20%-25% of the chord length of the runner blade body (2).

4. A Francis turbine runner blade with an adjustable nose flap as defined in claim 1, characterized in that: The thickness D of the leading edge flap (3) is equal to the thickness of the runner blade body (2).

5. A Francis turbine runner blade with an adjustable nose flap as claimed in any one of claims 1 to 4, characterized in that: The deflectable angle range of the leading edge flap (3) is 0-20°; the end close to the front edge of the runner blade body (2) is matched with the shape of the front edge of the runner blade body (2).

6. A Francis turbine runner blade with an adjustable nose flap as defined in claim 1, characterized in that: The length L2 of the flap head (4) in the leading edge flap (3) is twice the thickness of the runner blade body (2); the gap between the leading edge flap (3) and the runner blade body (2) is 1 / 10 of the width of the runner blade body (2).

7. A Francis turbine runner blade with an adjustable nose flap as defined in claim 1, characterized in that: The angle adjusting device (5) comprises a vane arm (5-1), a half key (5-2) and an end cover (5-3); one end of the vane arm (5-1) is connected with the end cover (5-3) through the half key (5-2), the other end of the vane arm (5-1) is connected with the crank arm (6); the end cover (5-3) is fixedly connected with the leading edge flap (3).

8. A Francis turbine runner blade with an adjustable nose flap as defined in claim 7, characterized in that: The end cover (5-3) comprises a cover body and a rotating shaft (5-4); the rotating shaft (5-4) is arranged at the center position of the cover body; the rotating shaft (5-4) is fixedly connected with the leading edge flap (3).

9. A Francis turbine runner blade with an adjustable nose flap as defined in claim 1, characterized in that: The crank arm (6) comprises two rectangular columnar rods and a rotating sleeve (10); the two columnar rods are connected through the rotating sleeve (10); the end of one columnar rod is provided with a screw hole (7), and the end of the other columnar rod away from the screw hole (7) is provided with a shaft hole (9).

10. A Francis turbine runner comprising at least a main shaft (11) and a back shroud (1); said main shaft (11) is placed in the center of the back shroud (1); characterized in that: It also comprises a plurality of mixed-flow water turbine runner blades with adjustable leading edge flaps as claimed in any one of claims 1-9; each leading edge flap (3) and angle adjusting device (5) are rotatably connected on the back cover plate (1), the other end of the crank arm (6) is connected with the main shaft (11); a plurality of runner blade bodies (2) are arranged in a spiral shape on the back cover plate (1) with the main shaft (11) as the center.

Images