A type of cross-flow water turbine with a bulb body featuring double helical blades and a rear-mounted bulb.

Abstract

This invention discloses a bulb-body rear-mounted cross-flow type fish-friendly water turbine with double helical blades. Its flow passage includes, in sequence, an inlet chamber, a guide cone, a guide vane area, a runner area with variable-pitch double helical blades, a tailrace diffuser section, and an extension section. The inlet chamber is a gradually deformed flow channel transitioning from inclined to horizontal, with a rectangular inlet and a circular outlet. The guide vane profile is a positive curvature crescent shape, employing variable-pitch double helical blades. The guide cone within the runner is a truncated cone with a cross-sectional area increasing along the streamline direction. The bulb body is rear-mounted. This invention targets tidal energy resources with high fish content, developing a bulb-body rear-mounted cross-flow type fish-friendly water turbine based on the characteristics of tidal energy. Its excellent hydraulic performance ensures power generation, and its good fish-passing performance opens up new directions for the development of hydroelectric generator sets, aiming to improve the economic and ecological benefits of hydropower projects and achieve coordinated green development of hydropower and aquatic ecology.

Description

Technical Field

[0001] This invention belongs to the field of hydraulic machinery and new energy technology, and in particular relates to a bulb-type cross-flow water turbine with double helical blades. Background Technology

[0002] Looking at the current state of global energy development, traditional fossil fuels face problems such as limited resources and severe pollution emissions. Therefore, the vigorous development of clean energy has become an inevitable trend. On the one hand, my country has vast sea areas and numerous islands, possessing abundant tidal energy resources that can be used for power generation to meet the growing electricity demand of national production. On the other hand, conventional hydroelectric generator units are difficult to apply to tidal power generation due to their complex structure and the potential for fatal harm to fish. Developing fish-friendly generator units is a requirement for the coordinated development of water conservancy and ecological engineering.

[0003] Domestic and international hydropower stations have constructed fish ladders, fish channels, fish lifts, and fish locks to allow fish to escape the flow of water through the turbine generator units. While this method is effective, it is costly in terms of both initial construction and subsequent maintenance. Furthermore, a large number of fish are still injured when carried into the turbine by the water flow. Therefore, a fish-friendly turbine unit is needed to fundamentally solve this problem. However, currently available technologies only include axial-flow fish-friendly turbine units. The flow path bends in these units not only significantly impact fish, but the traditional internal flow within the turbine also causes substantial mechanical damage, pressure damage, cavitation damage, and shear force damage to the fish. Summary of the Invention

[0004] This invention targets marine energy resources with extremely high fish content. Based on the characteristics of tidal energy, it develops a bulb-type cross-flow water turbine with double helical blades and a rear-mounted bulb body. The aim is to improve the economic and ecological benefits of hydropower projects and achieve coordinated green development of hydropower and water ecology.

[0005] The present invention adopts the following technical solution to achieve the following:

[0006] A bulb-body rear-mounted cross-flow type water turbine with double helical blades includes an inlet chamber, a guide vane area, guide vanes, a flow cone connected to the main shaft, a runner with variable pitch double helical blades, a bulb body, a bulb body support, a bulb body vertical shaft channel, and a tailrace pipe.

[0007] The inlet chamber, guide vane area, impeller chamber, and tailrace pipe are welded together in sequence. Variable pitch double helical blades are welded around the main shaft. The flow guide cone is welded and integrated on the left side of the main shaft inlet end. The bulb body is connected to the right side of the main shaft outlet end by a bearing. The bulb body support is connected to the lower side of the middle cylindrical section of the bulb body, supporting and fixing the bulb body horizontally placed in the tailrace pipe cavity. The bulb body vertical shaft channel is vertically welded to the upper side of the middle cylindrical section of the bulb body. Guide vanes are evenly distributed and welded between the upper and lower rings of the guide vanes. The entire unit is installed horizontally with the central axis of the main shaft as the reference.

[0008] A further improvement of the present invention is that the water inlet chamber is a gradually deformed flow channel that transitions from inclined to horizontal, the inlet has a rectangular cross section, the outlet has a circular cross section, the guide vane profile is a positive curvature crescent shape, the impeller blades are variable pitch double helical blades, and the internal flow guide cone of the impeller is a frustum with a cross-sectional area that increases along the streamline direction.

[0009] A further improvement of the present invention is that the front section of the inlet chamber is an inclined section with an inclination angle of 34° to 36°, the inlet cross section is a rectangle with a width of 2.5D1 and a height of 2.98D1, the outlet diameter is 1.8D1, the length of the inlet chamber flow channel is 4.396D1, and the ratio of the length of the inclined section L1 to the length of the straight section L2 is 0.96 to 0.97:1, where D1 is the diameter of the impeller.

[0010] A further improvement of this invention is that the single-row guide vanes are arranged in a ring, with 12 to 14 vanes, and the angle α1 between the guide vane axis and the turbine axis is 64° to 66°, and the guide vane throat diameter D... T The ratio of the guide vane diameter to the runner diameter D1 is 0.32, and the guide vane profile equation is:

[0011] A:

[0012] B:

[0013] A further improvement of the present invention is that the ratio of the axial length of the impeller to the impeller diameter D1 is 1:1.59 to 1.60.

[0014] A further improvement of the present invention is that the ratio of the initial pitch to the final pitch of the variable pitch double helix blade is 1:1.2 to 1.4, the blade has a constant radial diameter, and the blade thickness decreases outward along the radius.

[0015] The radial variation law of blade thickness δ is: δ=0.0749r+2.34

[0016] The equation C for the leaf bone line is:

[0017] Where β is the helix angle and the blade wedge angle θ is 1.2° to 3°.

[0018] A further improvement of the present invention is that a bulb support is placed at a distance of 1.15 to 1.2D1 from the inlet of the tailwater pipe, the maximum diameter of the middle section of the bulb is 1.3 to 1.4D1, and the wall thickness of the bulb is 0.034 to 0.036D1.

[0019] A further improvement of the present invention is that a vertical channel for entering and exiting the bulb body with a length of 0.31 to 0.33D1 and a width of 0.08 to 0.09D1 is provided on the upper part of the bulb body at a distance of 1.48 to 1.52D1 from the inlet of the tailwater pipe.

[0020] A further improvement of the present invention is that the cross-sectional area S of the drainage cone increases along the streamline direction, and the cross-sectional area S changes with the streamline as follows: S = 159.81h + 537.58, where h is the increment of the cross-sectional radius of the inner drainage cone along the streamline direction.

[0021] A further improvement of the present invention is that the angle α2 between the tailrace diffuser section and the rotor axis is 8° to 11°, the tailrace inlet diameter is 1.1 to 1.2D1, the tailrace outlet has a rectangular cross-section with a width of 1.4 to 1.5D1 and a height of 2.0 to 2.2D1, the tailrace length is 9 to 12D1, and the ratio of the length of the tailrace diffuser section L3 to the length of the extension section L4 is 1:12 to 12.5.

[0022] Compared with the prior art, the present invention has at least the following beneficial technical effects:

[0023] 1. This invention designs a bulb-type cross-flow water turbine with double helical blades. Compared with traditional cross-flow water turbines, this invention has invented a runner with variable pitch double helical blades. Its advantages are, firstly, that fewer blades increase the unit flow rate, and secondly, the helical blades increase the cross-sectional area of ​​the water passage. The combined effect of these two factors enhances the work capacity of the runner. Furthermore, the helical elongated flow channel provides a better space for fish to pass through the turbine, and the smaller pressure gradient change rate effectively reduces the damage to fish in the runner, further improving the fish passage rate.

[0024] 2. This invention designs a rear-mounted bulb-type cross-flow water turbine with double helical blades, employing a rear-mounted bulb body. Compared to units with a front-mounted bulb body in the inlet channel, its advantages are twofold: firstly, the inlet channel structure is simple, and the straight-through channel can collect water flow more efficiently with less head loss; secondly, by integrating the drain cone and bulb body to form a streamlined channel, it weakens or even eliminates the turbine outflow vortex to the greatest extent, further improving the turbine efficiency while controlling and guiding the fish outflow without causing vortex entrainment and collision. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the structure of a bulb-type cross-flow water turbine with double helical blades rear-mounted, according to the present invention.

[0026] Figure 2 This is a schematic diagram of the guide vane structure of a water turbine.

[0027] Figure 3 for Figure 2 A schematic diagram of the guide vane profile of a medium-pressure turbine.

[0028] Figure 4 This is a schematic diagram of a variable pitch double helical blade for a water turbine.

[0029] Figure 5 for Figure 4 Schematic diagram of the runner flow channel structure of a medium-pressure turbine.

[0030] Figure 6 This is a schematic diagram of the tailrace pipe structure of a water turbine.

[0031] Explanation of reference numerals in the attached figures:

[0032] 1-Inlet chamber, 2-Guide vane area, 3-Guide vane body, 4-Drainage cone, 5-Main shaft, 6-Variable pitch double helix blade, 7-Rotator, 8-Bulb body, 9-Bulb body support, 10-Bulb body shaft channel, 11-Tailpipe diffuser section, 12-Tailpipe extension section. Detailed Implementation

[0033] To make the objectives, features, and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0034] like Figure 1-6 As shown, the present invention provides a bulb-body rear-mounted cross-flow type water turbine with double helical blades, including an inlet chamber 1, a guide vane area 2, a guide vane body 3, a flow guide cone 4, a main shaft 5, variable pitch double helical blades 6, a runner 7, a bulb body 8, a bulb body support 9, a bulb body vertical shaft channel 10, a tailrace diffuser section 11, and a tailrace extension section 12.

[0035] The inlet chamber 1, guide vane area 2, impeller 7, tailrace diffuser section 11, and tailrace extension section 12 are connected in sequence. Variable pitch double helical blades 6 are welded around the main shaft 5. The flow guide cone 4 is welded and integrated on the left side of the main shaft 5. The bulb body 8 is connected to the right side of the main shaft 5 by a bearing. The bulb body support 9 is connected to the lower side of the middle cylindrical section of the bulb body 8, supporting and fixing the bulb body 8 horizontally placed in the tailrace cavity. The bulb body vertical shaft channel 10 is vertically welded to the upper side of the middle cylindrical section of the bulb body 8. The guide vanes 3 are evenly distributed and welded between the upper and lower rings of the guide vane area 2. The entire unit is installed horizontally with the central axis of the main shaft 5 as the reference. The inlet chamber 1 is a gradually deformed flow channel that transitions from inclined to horizontal. The inlet has a rectangular cross section, and the outlet has a circular cross section. The guide vane 3 has a positive curvature crescent shape. The blades of the impeller 7 are variable pitch double helical blades 6. The flow guide cone 4 inside the impeller is a truncated cone with a cross-sectional area that increases along the streamline direction.

[0036] When the turbine is running, the water first enters the inlet chamber, which is a gradually deformed flow channel that transitions from an inclined section to a horizontal section. The front section of the inlet chamber is an inclined section with an inclination angle of 35°. The inlet cross-section is a rectangle with a width of 2.5D1 and a height of 2.98D1, and the outlet diameter is 1.8D1. The length of the inlet chamber flow channel is 4.396D1, and the ratio of the inclined section L1 to the straight section L2 is 0.963:1, where D1 is the runner diameter.

[0037] The intake chamber collects water flow and introduces it into the guide vane area before the runner. Fourteen single-row guide vanes are arranged in a ring, with the guide vane axis forming an angle α1 of 65° with the turbine's central axis. The guide vane throat diameter D... T The ratio of the guide vane diameter to the runner diameter D1 is 0.32, and the equation for the positive curvature crescent-shaped guide vane profile is:

[0038] A:

[0039] B:

[0040] The water flow forms a circulation within the guide vane region and enters the impeller along the direction guided by the water guiding mechanism. The variable-pitch double-helix blade surface is a three-dimensional variable-pitch helical surface. The ratio of the initial pitch to the final pitch of the variable-pitch double-helix blade is 1:1.354. The blade has a constant radial diameter, and its thickness decreases outwards along the radius. The ratio of the impeller's axial length to its diameter is 1:1.594. Figure 6 The thickness δ of the blade shown varies radially as δ = 0.0749r + 2.34, the blade wedge angle θ is 2°, and the blade rib line equation C is:

[0041] Where β is the helix angle.

[0042] After completing its work, the water flows out along the tailrace pipe. A bulb body is placed and fixed 1.181D1 from the tailrace pipe inlet, providing support. The bulb body has a vertical shaft channel for entry and exit. The cross-sectional area S of the guide cone increases with the streamline, following the formula: S = 159.81h + 537.58, where h is the increase in the cross-sectional radius of the inner guide cone along the streamline direction. The angle α2 between the tailrace pipe diffuser section and the impeller axis is 10.31°. The tailrace pipe inlet diameter is 1.142D1, and the tailrace pipe outlet has a rectangular cross-section with a width of 1.432D1 and a height of 2.04D1. The tailrace pipe length is 10.983D1, and the ratio of the length of the tailrace pipe diffuser section L3 to the length of the extension section L4 is 1:12.352.

[0043] Calculations and verifications have shown that the bulb-shaped, rear-mounted, cross-flow, fish-friendly water turbine provided by this invention possesses excellent hydraulic performance and fish passage capabilities. The extended, variable-pitch double-helix blades ensure hydraulic efficiency while providing an excellent fish passage channel. The hollow inlet chamber efficiently diverts water, and the rear-mounted exhaust cone and bulb-shaped structure together form a streamlined channel, eliminating vortices in the runner's outflow. This bulb-shaped, rear-mounted, fish-friendly water turbine demonstrates superior performance in tidal power generation, traditional cross-flow hydropower station generation, and other low-head hydropower conversion applications, serving as a reference case for the future development of ecological hydraulic machinery.

[0044] The principle of this invention is as follows: This invention provides a bulb-type cross-flow water turbine with double helical blades, which converts the energy of water flow into mechanical energy. This device can be used for tidal energy development to support the development of new energy sources. Its hollow inlet chamber adopts a transition from a rectangular cross-section to a circular cross-section to maximize water collection capacity. The water guiding mechanism connected to the inlet chamber has a single row of evenly distributed positive curvature guide vanes. As the water flows through them, it forms a circulation while flowing into the runner along the guide vane profile. The extended helical double blades inside the runner ensure hydraulic performance while the continuous flow channel effectively reduces the damage rate of fish passing through the machine. The water flow and fish exit from the runner and enter the tailrace pipe. A drain cone and bulb body are installed at the inlet of the tailrace pipe to effectively weaken or even eliminate the vortex at the runner outlet, thereby improving the hydraulic efficiency of the water turbine while reducing the impact of fish caught in the vortex within the tailrace pipe.

[0045] The descriptions not covered in the specific implementation of this invention are well-known in the art and can be implemented with reference to well-known techniques. The above specific embodiments and examples are specific support for the technical concept of a bulb-body rear-mounted cross-flow type water turbine with double helical blades proposed in this invention, and should not be used to limit the scope of protection of this invention. Any equivalent changes or modifications made on the basis of this technical solution in accordance with the technical concept proposed in this invention shall fall within the scope of protection of this invention.

Claims

1. A bulb-type cross-flow water turbine with double helical blades and a rear-mounted bulb body, characterized in that, It includes an inlet chamber (1), a guide vane area (2), a guide vane body (3), a flow cone (4) connected to the main shaft (5), a rotor (7) with variable pitch double helical blades (6), a bulb body (8), a bulb body support (9), a bulb body shaft channel (10), a tailwater pipe diffuser section (11), and a tailwater pipe extension section (12). The inlet chamber (1), guide vane area (2), impeller (7), tailwater pipe diffuser section (11) and tailwater pipe extension section (12) are connected in sequence. The variable pitch double helix blade (6) is welded around the main shaft (5). The diversion cone (4) is welded and integrated on the left side of the main shaft (5). The bulb body (8) is connected to the right side of the main shaft (5) with a bearing. The bulb body support (9) is connected to the lower side of the middle cylindrical section of the bulb body (8). The bulb body (8) is supported and fixed to be placed horizontally in the tailwater pipe cavity. The bulb body vertical shaft channel (10) is vertically welded to the upper side of the middle cylindrical section of the bulb body (8). The guide vane body (3) is evenly welded between the upper and lower rings of the guide vane area (2). The whole unit is installed horizontally with the central axis of the main shaft (5) as the reference. The inlet chamber (1) is a gradually deformed flow channel that transitions from inclined to horizontal. The inlet has a rectangular cross section, and the outlet has a circular cross section. The guide vane (3) has a positive curvature crescent shape. The blades of the impeller (7) are variable pitch double helical blades (6). The impeller guide cone (4) is a frustum with a cross-sectional area that increases along the streamline direction. The single-row guide vanes (3) are arranged in a ring, with 12 to 14 guide vanes (3). The angle between the axis of the guide vane (3) and the axis of the turbine is [missing information]. α 1 is 64°~66°, guide vane body (3) throat diameter D T The ratio of the guide vane diameter to the diameter D1 of the runner (7) is 0.32, and the guide vane profile equation is: A： B: 。 2. A bulb-type cross-flow turbine with double helical blades and a rear-mounted bulb body, as described in claim 1, is characterized in that... The front section of the inlet chamber (1) is an inclined section with an inclination angle of 34° to 36°. The inlet cross section is a rectangle with a width of 2.5D1 and a height of 2.98D1. The outlet diameter is 1.8D1. The flow channel length of the inlet chamber (1) is 4.396D1. The ratio of the length of the inclined section L1 to the length of the straight section L2 is 0.96 to 0.97:1, where D1 is the diameter of the impeller.

3. The bulb-body rear-mounted cross-flow type water turbine with double helical blades according to claim 1, characterized in that, The ratio of the axial length of the impeller (7) to the impeller diameter D1 is 1:1.59~1.

60.

4. A bulb-body rear-mounted cross-flow type water turbine with double helical blades as described in claim 1, characterized in that, A bulb support (9) is placed 1.15 to 1.2D1 away from the tailwater inlet. The maximum diameter of the middle section of the bulb body (8) is 1.3 to 1.4D1, and the wall thickness of the bulb body (8) is 0.034 to 0.036D1.

5. A bulb-body rear-mounted cross-flow type water turbine with double helical blades as described in claim 4, characterized in that, A vertical shaft passage (10) with a length of 0.31 to 0.33D1 and a width of 0.08 to 0.09D1 is provided on the upper part of the bulb body (8) at a distance of 1.48 to 1.52D1 from the inlet of the tailwater pipe.

6. A bulb-type cross-flow turbine with double helical blades and a rear-mounted bulb body, as described in claim 1, is characterized in that... The cross-sectional area S of the flow-guiding cone (4) increases along the streamline direction, and the cross-sectional area... S The variation law with streamlines is as follows: ,in h This represents the increment of the cross-sectional radius of the flow-guiding cone along the streamline direction.

7. A bulb-type cross-flow turbine with double helical blades and a rear-mounted bulb body, as described in claim 1, is characterized in that... The angle between the tailrace diffuser section (11) and the rotor axis α 2 is 8°~11°, the inlet diameter of the tailwater pipe is 1.1~1.2D1, the outlet of the tailwater pipe is a rectangular cross section with a width of 1.4~1.5D1 and a height of 2.0~2.2D1, the length of the tailwater pipe is 9~12D1, and the ratio of the length of the tailwater pipe diffuser section L3 to the length of the extension section L4 is 1:12~12.5.

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