Hydraulic turbine

Abstract

A runner for a hydraulic turbine includes a hub and a plurality of pivotable blades extending from the hub. Each pivotable blade of the plurality of pivotable blades includes a blade root at the hub, a blade tip opposite the blade root, and a leading edge. Each pivotable blade of the plurality of pivotable blades is pivotable relative to the hub about a respective pivot axis. For at least one blade, the leading edge at the blade root is positioned along a radial axis of the runner, and the leading edge at the blade tip cantilevers out of the radial axis in a circumferential direction of the runner.

Description

Cross-references to related applications

[0001] This application claims priority to U.S. Provisional Application No. 63 / 536,266, filed September 1, 2023, which is incorporated herein by reference in its entirety. Technical Field

[0002] This invention relates to a hydroelectric turbine runner. Specifically, the invention relates to a turbine runner configured to facilitate the safe downstream passage of fish or other aquatic organisms through the turbine, while achieving high efficiency over a wide operating range. Background Technology

[0003] The demand for hydroelectric power plants with minimal environmental impact is growing. To reduce environmental impact, it is desirable for hydroelectric power plants to have minimal impact on fish and other aquatic life (e.g., not harming aquatic life and avoiding obstruction of their movement or migration). There is also a desire to construct hydroelectric power plants with high efficiency and relatively low installation, operation, and maintenance costs. Sometimes, it is also desirable to retrofit existing hydroelectric power plants with new turbines to reduce environmental impact and / or improve efficiency.

[0004] Therefore, there is still a need in the art for a turbine that allows fish and other aquatic organisms to safely pass downstream through the turbine, and that is highly efficient, has relatively low installation, operation and maintenance costs, and can be used in a wide range of applications (including retrofit installations). Summary of the Invention

[0005] A runner for a hydraulic turbine may include a hub and a plurality of pivotable blades extending from the hub. Each of the plurality of pivotable blades may include a blade root located at the hub, a blade tip opposite to the blade root, and a leading edge. Each of the plurality of pivotable blades can pivot relative to the hub about its respective pivot axis. The thickness T of the leading edge. LE With respect to the diameter D of the wheel RThe ratio can range from about 0.03 to about 0.35. For at least one blade, the leading edge at the blade root can be positioned along the radial axis of the runner, and the leading edge at the blade tip can be cantilevered beyond the radial axis in the circumferential direction of the runner. The runner can include a ratio of the runner's axial length to its diameter, said ratio being less than 0.55. The runner can include a ratio of the chord length at the tip of each pivotable blade to the runner's diameter, said ratio being less than 0.9. The runner can be configured such that each pivot axis forms an angle between about 8 degrees and about 155 degrees relative to the runner's axis. The runner can be configured such that each pivot axis forms an angle between about 30 degrees and about 100 degrees relative to the runner's axis. The runner can be configured such that each pivot axis forms an angle between about 90 degrees relative to the runner's axis. During the blade's rotation from maximum pitch to minimum pitch, the outer surface of the hub may be swept by the blade root of each pivotable blade, and said outer surface may be spherical. During the rotation of the blades from the maximum pitch to the minimum pitch, the root of each pivotable blade can conform to the shape of the outer surface of the hub. Within the pivoting range of the blades from the maximum pitch to the minimum pitch, the tip of each pivotable blade can have a generally spherical swept shape. The thickness of the leading edge of each pivotable blade can be between about 100 mm and about 700 mm. A portion of the leading edge at the tip of each pivotable blade can be inclined at an angle between about 20 degrees and about 90 degrees relative to the radial axis of the runner. A portion of the leading edge at the tip of each pivotable blade can be inclined at an angle between about 25 degrees and about 45 degrees relative to the radial axis of the runner. When viewed along an axis perpendicular to the axial axis of the runner, the leading edge of each pivotable blade can be arc-shaped. When viewed along an axis perpendicular to the axial axis of the runner, the leading edge of each pivotable blade can bend at the root away from the upstream end of the runner and then bend back towards the upstream end of the runner towards the tip. The radius of curvature of one or more surfaces can be greater than the radius of curvature of the rounded edge of the hub. The first part of the trailing edge can be concave, the second part of the trailing edge can be convex, and the first part of the trailing edge can be positioned closer to the hub than the second part of the trailing edge. The ratio of the chord length at the tip of each pivotable blade to the chord length at the root of each pivotable blade can be from about 1.6 to about 2.5.

[0006] The runner can be used in a turbine, positioned within a casing that defines an inlet and an outlet for fluid flow. During blade rotation from maximum pitch to minimum pitch, the tip of each pivotable blade can conform to the shape of the discharge ring of the casing. During blade rotation from maximum pitch to minimum pitch, the inner surface of the discharge ring of the casing, swept by the tip of each pivotable blade, can be spherical. The discharge ring of the casing can have a removable section that is removably assembled from the outside or inside of the turbine. The discharge ring of the casing can be axially split. The discharge ring of the casing can be radially split. The turbine may include a generator, such as a constant-speed generator or a variable-speed generator, operatively coupled to the runner.

[0007] Some embodiments described herein relate to a runner for a hydraulic turbine, which may include a hub and a plurality of pivotable blades extending from the hub. Each of the plurality of pivotable blades may include a blade root located at the hub, a blade tip opposite to the blade root, and a leading edge opposite to the trailing edge. Each of the plurality of pivotable blades may pivot relative to the hub about its respective pivot axis. For at least one blade, the leading edge at the blade root may be positioned along the radial axis of the runner, and the leading edge at the blade tip may cantilever beyond the radial axis in the circumferential direction of the runner. The thickness T of the leading edge... LE With respect to the diameter D of the wheel R The ratio is in the range of approximately 0.03 to approximately 0.35. The leading edge thickness can be greater than the trailing edge thickness. In the meridional section, the trailing edge at the leaf root can be positioned further downstream than the trailing edge at the leaf tip.

[0008] In any of the various embodiments described herein, for at least one of a plurality of pivotable blades, the trailing edge may extend rearward toward the downstream end of the hub. In some examples, at least one of the plurality of pivotable blades has a cross-section at the blade root, the surface curvature of said cross-section having a first shape and a second shape, wherein the first shape is concave and the second shape is convex.

[0009] In any of the various embodiments described herein, the hub may include a plurality of surfaces, which may be planar and are radially spaced about the longitudinal axis of the hub. In some embodiments, the trailing edge of one of the plurality of pivotable blades may be arched upstream between the tip and root of the pivotable blade. Attached Figure Description

[0010] The accompanying drawings, which are incorporated herein and form part of the specification, illustrate the present disclosure and, together with the description, further serve to explain the principles of the present disclosure and enable those skilled in the art to make and use the present disclosure.

[0011] Figure 1It is a perspective view of the runner for a hydraulic turbine according to the implementation plan.

[0012] Figure 2 It is based on Figure 1 Another perspective view of the rotating wheel.

[0013] Figure 3 It is based on Figure 1 Another perspective view of the rotating wheel.

[0014] Figure 4 It is based on Figure 1 An upstream view of the rotor.

[0015] Figure 5 It is based on Figure 1 Downstream view of the rotor.

[0016] Figure 6 It is based on Figure 1 Side view of the rotating wheel.

[0017] Figure 7 It is based on Figure 1 Another side view of the rotating wheel.

[0018] Figure 8 It is based on Figure 1 Another side view of the rotating wheel.

[0019] Figure 9 It is based on Figure 1 Another side view of the rotating wheel.

[0020] Figure 10 It is based on Figure 1 The rotating wheel Figure 6 A cross-sectional view taken at line X–X'.

[0021] Figure 11 It is based on Figure 1 Another side view of the rotor, with the blades adjusted to a 5-degree angle.

[0022] Figure 12 It is based on Figure 1 Another side view of the rotor, with the blades adjusted to a 10-degree angle.

[0023] Figure 13 It is based on Figure 1 Another side view of the rotor, with the blades adjusted to an angle of 17 degrees.

[0024] Figure 14 The following is illustrated: installation in a hydraulic turbine according to an embodiment. Figure 1 The rotor, in which the blades are adjusted to an angle of 5 degrees.

[0025] Figure 15The following is illustrated: installation in a hydraulic turbine according to an embodiment. Figure 1 The rotor, in which the blades are adjusted to a 10-degree angle.

[0026] Figure 16 The following is illustrated: installation in a hydraulic turbine according to an embodiment. Figure 1 The rotor, in which the blades are adjusted to an angle of 17 degrees.

[0027] Figure 17 A runner installed in a hydraulic turbine according to an embodiment is shown.

[0028] Figure 18 A runner for a hydraulic turbine according to an embodiment is shown.

[0029] Figure 19 A runner for a hydraulic turbine according to an embodiment is shown.

[0030] Figure 20 It is a partial cross-sectional view of the runner for a hydraulic turbine according to the implementation plan.

[0031] Figure 21 A top view of a runner for a hydraulic turbine according to an embodiment is shown.

[0032] Figure 22 A perspective view of a runner for a hydraulic turbine according to an embodiment is shown.

[0033] Figure 22A A perspective view of a runner for a hydraulic turbine according to an embodiment is shown, which has a discharge ring with a split surface.

[0034] Figure 23 A side view of a runner for a hydraulic turbine according to an embodiment is shown, with the blades adjusted toward the closed position.

[0035] Figure 24 A side view of a runner for a hydraulic turbine according to an embodiment is shown, with the blades adjusted toward the open position.

[0036] Figure 25A A side view of a runner for a hydraulic turbine according to an embodiment is shown, with the blades adjusted toward the open position.

[0037] Figure 25B It shows Figure 25A The cross-section of a leaf taken at the leaf base, midrib, and leaf tip.

[0038] Figure 26 A rear perspective view of a runner for a hydraulic turbine according to an embodiment is shown, with the blades adjusted toward the closed position.

[0039] Figure 27 A perspective view of a runner for a hydraulic turbine according to an embodiment is shown.

[0040] Figure 28 A graph comparing the normalized chord length distribution of conventional blades and blades of this disclosure is shown. Detailed Implementation

[0041] In the following description, numerous specific details are set forth to provide a thorough understanding of embodiments of this disclosure. However, it will be apparent to those skilled in the art that embodiments, including structures, systems, and methods, can be practiced without these specific details. The descriptions and illustrations herein are common means used by those experienced or skilled in the art to most effectively communicate the substance of their work to others skilled in the art. In other instances, well-known methods, processes, components, and circuit systems have not been described in detail to avoid unnecessarily obscuring aspects of this disclosure.

[0042] References to "an embodiment," "an embodiment," "an exemplary embodiment," etc., in the specification indicate that the described embodiment may include a particular feature, structure, or characteristic; however, each embodiment may not necessarily include that particular feature, structure, or characteristic. Furthermore, such wording does not necessarily refer to the same embodiment. Moreover, when a particular feature, structure, or characteristic is described in connection with an embodiment, it should be assumed that, whether explicitly described or not, implementing such a feature, structure, or characteristic in conjunction with other embodiments is within the knowledge of a person skilled in the art.

[0043] As used herein, the terms “about” or “approximately” may refer to the stated quantity or value ±5%.

[0044] The following examples are illustrative of this disclosure and not limiting. Other suitable modifications and alterations to various conditions and parameters that are commonly encountered in the art and obvious to those skilled in the art are within the spirit and scope of this disclosure.

[0045] Modern hydroelectric facilities are typically required to meet stringent environmental sustainability standards. Hydroelectric plants operating at heads of approximately 60 meters or less often disrupt natural ecosystems, particularly the upstream and downstream movement of fish and other aquatic life. However, hydroelectric development in this range is still desirable due to the relative availability of such installation sites. Medium-head applications (e.g., heads greater than 30 meters) are particularly desirable because they offer relatively higher power densities compared to low-head sites.

[0046] Some embodiments described herein provide runners for hydraulic turbines of various sizes, including high-head, medium-head, and low-head applications. Some embodiments include runners for use in low-head to medium-head applications (e.g., in the range of approximately 3 meters to approximately 40 meters), which allows fish to safely pass downstream through a turbine incorporating said runner. Some embodiments described herein also achieve high efficiency with relatively low installation, operating, and maintenance costs. Some embodiments described herein also achieve high efficiency over a wide flow range. Some embodiments described herein can be used in a wide range of applications, including retrofitting, refurbishment, modernization, and upgrade installations.

[0047] In some implementations, the runner has blades with adjustable pitch. This can, for example, help achieve high efficiency over a wide range of flow rates.

[0048] In some embodiments, the blade's pivot axis is angled relative to the runner's axis of rotation. For example, an angled pivot axis can enable blades with adjustable pitch, while also allowing for blade features described below (e.g., thick leading edge or cantilevered leading edge). An angled pivot axis can also allow essentially diagonal flow through the runner blades, as found in the Delia turbine. In some embodiments, the blade's pivot axis is chosen to minimize the turbine size required to accommodate the blade's pivoting range. In one aspect, the blade's pivot axis can be perpendicular to the axis of rotation.

[0049] In some implementations, the turbine blades have thick leading edges relative to the size of fish allowed to pass through the turbine. Fish surviving a blade impact are highly sensitive to both the ratio of fish body length to the thickness of the turbine blade leading edge and the velocity. For example, after a blade impact at a velocity of 7 m / s, blades with a fish body length-to-blade thickness ratio <1 allow for approximately 100% fish survival, while at an impact velocity of 12 m / s, they allow for >approximately 90% fish survival. Therefore, fish encountering blades with thick leading edges are more likely to survive a blade impact than those encountering blades with thinner leading edges.

[0050] In some implementations, the leading edge of the rotor blades is arc-shaped when viewed along the rotor's axis. Therefore, the orthogonal component of the impact velocity... w N = w sin(a) This reduces the risk of fish mortality due to collisions with leaves.

[0051] In some implementations, the leading edge of the blades of the rotor is arc-shaped when viewed along an axis perpendicular to the rotor's axis (i.e., from one side of the rotor).

[0052] In some implementations, the leading edge of the rotor blades is twisted. This shape allows for minimizing the cantilever required at the blade tip of the leading edge, while still maintaining a low probability of impact along the leading edge. w N Minimize the orthogonal components to achieve the maximum possible overall fish survival rate along the leading edge.

[0053] In some implementations, the runner is integrated into the turbine.

[0054] In some embodiments, the runner is a Kaplan turbine runner. In some embodiments, the runner is a Delia turbine runner.

[0055] These and other implementation schemes are discussed in more detail below with reference to the accompanying drawings.

[0056] Figures 1 to 13 A rotary wheel 100 according to some implementation schemes is shown. Figure 1 A perspective view of the rotary wheel 100 is shown. Figure 2 Another perspective view of the rotary wheel 100 is shown. Figure 3 Another perspective view of the rotary wheel 100 is shown. Figure 4 An upstream view of the rotor 100 is shown. Figure 5 A downstream view of the rotor 100 is shown. Figure 6 A side view of the rotary wheel 100 is shown. Figure 7 Another side view of the rotary wheel 100 is shown. Figure 8 Another side view of the rotary wheel 100 is shown. Figure 9 Another side view of the rotary wheel 100 is shown. Figure 10 The rotating wheel 100 is shown in Figure 6 A cross-sectional view taken at line X–X'. Figure 11 Another side view of the rotor 100 is shown, with the blades adjusted to an angle of 5 degrees. Figure 12 Another side view of the rotor 100 is shown, with the blades adjusted to an angle of 10 degrees. Figure 13 Another side view of the rotor 100 is shown, with the blades adjusted to an angle of 17 degrees.

[0057] The rotor 100 can be configured to rotate circumferentially 170 about a shaft axis 150 during use to drive a load, such as a generator, which may be a generator with a constant speed shaft. Figure 4 In the illustrated embodiment, for example, when viewed from the upstream side of the rotor 100, the circumferential direction 170 is counterclockwise. However, in other embodiments, when viewed from the upstream side of the rotor 100, the circumferential direction 170 may be clockwise.

[0058] The impeller 100 may include a hub 110 and a plurality of blades 120 extending from the hub 110. In some embodiments, the blades 120 are evenly spaced around the circumference of the hub 110. In some embodiments, the blades 120 are arranged in a helical pattern on the hub 110.

[0059] In some implementations, each of the plurality of blades 120 of the rotor 100 has the same shape and size.

[0060] exist Figure 1 In the illustrated embodiment, the impeller 100 includes five blades 120. However, in other embodiments, the impeller 100 may include two blades, three blades, four blades, or more than five blades.

[0061] Each blade 120 of the impeller 100 may include a blade root 122 located at the hub 110, a blade tip 124 opposite to the blade root 122 and defining the outermost extent of the blade 120, a leading edge 126 located at the upstream portion of the impeller 100, a trailing edge 128 located at the downstream portion of the impeller 100, a pressure surface 130 located on the upstream side of the blade 120, and a suction surface 132 located on the downstream side of the blade 120.

[0062] In some embodiments, blade 120 is an adjustable-pitch blade. This can, for example, contribute to high efficiency over a wide flow range (e.g., where rotor 100 drives a generator with a constant-speed shaft). In some such embodiments, for example, as... Figure 10 As shown, the blades 120 of the rotor 100 include a pivot end 123, which is pivotally connected within the hub 110 to a blade link 111 of the hub 110. The connection between the pivot end 123 and the blade link 111 allows the blades 120 of the rotor 100 to pivot relative to the hub 110 about their respective pivot axes 180. In some embodiments, the control system of the rotor 100 can control the pivoting of the blades 120 relative to the hub 110 by pivoting the pivot end 123 and / or the blade link 111.

[0063] In some implementations, the blade 120 can pivot within a pivot range starting from 0 degrees when fully open, thus spanning from a blade angle of 5 degrees to 25 degrees. For example, as Figures 11 to 13 As shown, blade 120 can pivot to an angle of 5 degrees. Figure 11 ), 10 degrees angle ( Figure 12 or an angle of 17 degrees ( Figure 13To achieve high efficiency within the flow range. In some embodiments, 120 can pivot within a pivot range of approximately 15 degrees. In some embodiments, 120 can pivot within a pivot range of approximately 20 degrees. In some embodiments, 120 can pivot within a pivot range of approximately 25 degrees.

[0064] In some implementations, blade 120 can pivot to close the impeller and prevent water from flowing through it.

[0065] In some embodiments, the pivot axis 180 of the blade 120 is angled relative to the axis 150 of the rotor 100. The pivot axis 180 may be perpendicular to the axis 150 or may not be perpendicular. For example, the pivot axis 180 of the blade 120 may be angled relative to the axis 150 of the rotor 100 at an angle β greater than 90 degrees, such that the pivot axis 180 of the blade 120 is angled downstream. Figure 10 In one embodiment, for example, the pivot axis 180 is at an angle of approximately 97 degrees relative to the axis. In other embodiments, the pivot axis 180 may be at an angle of approximately 8 degrees to approximately 45 degrees relative to the axis.

[0066] The position of the pressure center relative to the blade pivot axis 180° and the position of the blade's center of mass (see, for example, see...). Figures 19 to 20The hydraulic pressure distribution significantly influences the mechanical load on the blade pivoting actuation system and the turbine's operational behavior. Generally, it is necessary to select whether pivotable turbine blades exhibit automatic closing or automatic opening behavior. The decision to choose automatic closing or automatic opening involves considering numerous factors, and both options are likely common in practice. For example, an automatic opening design might be preferred to limit the maximum runaway speed to protect associated equipment, such as generators. On the other hand, automatic closing behavior may facilitate easier blade adjustments during load follow. Under maximum power output conditions, the pressure center may be radially located near the midspan of the blade, closer to the trailing edge than the leading edge, such as at approximately 60% to 80% of the midspan chord length. Typically, the blade pivot axis will be located at approximately 20% to 30% of the midspan chord length. Therefore, the hydraulic pressure distribution will tend to generate a closing moment around the blade pivot axis. The location of the blade's center of mass can be selected by taking into account the hydraulic load, allowable stresses, and available space for the actuation system components. Generally, if the blade's center of mass is located downstream of the blade pivot, the blade will exhibit automatic closing behavior as the runner rotates around the axis. Conversely, if the blade's center of mass is located upstream of the blade pivot, the blade will exhibit automatic opening behavior. Positioning the blade's center of mass closer to the blade pivot tends to reduce the magnitude of the moment of inertia. The location of the blade's center of mass can be determined by the thickness distribution and positioning of the blade geometry, as well as the mass distribution within the blade. For example, hollow blades can be constructed by varying the wall thickness to help position the blade's center of mass relative to the blade pivot axis.

[0067] In some implementations, the blade pivot axis can be perpendicular to the shaft axis. This configuration allows for a simplified actuation system compared to implementations using a blade pivot axis that is not perpendicular to the shaft axis. For example, a blade pitch angle adjustment system uses a set of mechanical linkages, such as... Figure 20 As shown, if the blade pivot axis is not perpendicular to the shaft axis, a ball joint can be used. However, if the blade pivot axis is perpendicular to the shaft axis, a cylindrical bushing or bearing can be used.

[0068] For example, such as Figure 1 and Figure 10As shown, the shape of the blade root 122 of each pivotable blade 120 can conform to the shape of the outer surface of the hub 110 during the rotation of the blade 120 from its maximum pitch to its minimum pitch. For example, in some embodiments, the outer surface of the hub 110 swept by the blade root 122 from the maximum pitch to the minimum pitch of the blade 120 is spherical, and the blade root 122 at the hub 110 can have a generally spherical swept shape within the pivoting range of the blade 120 from its maximum pitch to its minimum pitch. For example, this can reduce the clearance between the hub 110 and the blade root 122 within the pivoting range of the blade 120 from its maximum pitch to its minimum pitch. The clearance between the hub 110 and the blade root 122 can be dangerous for fish, as they may become trapped in the clearance and then be cut off or otherwise injured. Gaps can also lead to hydraulic efficiency losses, as well as localized turbulence, high velocities, and associated fluid shear forces, and potential cavitation.

[0069] In some implementations, the runner 100 is integrated into the turbine 200 (e.g., in...). Figures 14 to 16 (As shown in the diagram). In some embodiments, the shape of the blade tip 124 of each pivotable blade 120 may conform to the shape of the inner surface of the turbine 200 housing during rotation of the blade 120 from its maximum pitch to its minimum pitch. For example, in some embodiments, the inner surface of the turbine 200 housing swept by the blade tip 124 from the maximum pitch to the minimum pitch of the blade 120 is spherical, and the blade tip 124 may have a generally spherical swept shape during the pivoting range of the blade 120 from its maximum pitch to its minimum pitch. This, for example, can reduce the clearance between the blade tip 124 and the turbine 200 housing during the pivoting range of the blade 120 from its maximum pitch to its minimum pitch. The clearance between the blade tip 124 and the turbine 200 housing can be dangerous to fish, as they may become trapped in the clearance and then be cut off or otherwise injured. Gaps can also lead to hydraulic efficiency losses, as well as localized turbulence and potential cavitation.

[0070] In some implementations, the diameter D of the spherical hub sph_h With the diameter D of the wheel R The ratio is approximately 0.4 to 0.5, such as approximately 0.42 to 0.45.

[0071] exist Figures 10 to 16In the illustrated embodiments, the clearance at the hub 110 is reduced (due to the generally spherical shape of the hub 110 at the blade root 122 and the generally spherical shape of the blade root 122 at the hub 110), and the clearance at the blade tip 124 is reduced (due to the generally spherical swept shape of the blade tip 124 within the pivot range of the blade 120 and the generally spherical shape of the turbine 200 housing at the blade tip 124). However, in some embodiments, the clearance at the hub 110 is reduced, but the clearance at the blade tip 124 is not reduced. For example, in some embodiments, the trailing edge 128 may be overhanging (i.e., extending beyond the spherical portion of the turbine 200 housing, such as...). Figure 17 As shown, this makes it impossible to minimize the clearance at the blade tip 124. For example, this could allow a larger flow rate through the turbine 100 while maximizing the blade surface area to reduce the risk of cavitation (compared to a runner without a trailing edge overhang). In some examples, the leading edge 126 does not overhang or extend upstream of the turbine housing's discharge ring and may be parallel to or below the upstream end of the discharge ring. This is because an overhang at the leading edge could increase the risk of injury to fish entering the turbine runner. However, in some embodiments, the leading edge of the runner may overhang or extend upstream of the housing's discharge ring. This may occur when a runner with a spherical geometry is mounted in a turbine housing with a cylindrical shape, which can provide improved fish safety compared to conventional turbine runners.

[0072] In some embodiments, the turbine 200 housing includes a discharge ring (e.g., a spherical discharge ring). In some embodiments, the discharge ring has a removable section that is removably assembled from the outside or inside of the turbine. In some embodiments, the discharge ring is axially split (e.g., for removal along the shaft axis 150). In some embodiments, the discharge ring is radially split (e.g., for removal perpendicular to the shaft axis 150).

[0073] For example, such as Figure 6 As shown, the blade 120 can have a thickness of T. LE Thick leading edge 126.

[0074] In some implementations, the leading edge thickness T of the blade 120 LE It can be at least about 50 mm. In some embodiments, the leading edge thickness T of the blade 120 LE The length of the fish of interest in the area where the turbine, including the impeller 100, will be installed can be equal to or greater than the length of the fish in the area. For example, juvenile salmon have an average length of about 100 mm to 200 mm. Therefore, the leading edge thickness T of the blade 120 intended for use in the area with juvenile salmon is... LEThe thickness can be 100 mm to 200 mm or greater. In areas where adult migrating eels are present, the leading edge thickness may need to be 75 mm to 200 mm or greater, and it may be important to avoid gaps (such as at the leading edge and hub or the leading edge and exhaust ring) that could trap and cut off slender fish like eels. In some examples, the leading edge thickness can be between approximately 100 mm and approximately 700 mm.

[0075] In some implementations, the leading edge thickness T LE With the diameter D of the wheel R The ratio (i.e., T) LE / D R The value can be from about 0.03 to about 0.35, such as from about 0.06 to about 0.25, such as from about 0.08 to about 0.14.

[0076] In some embodiments, the thickness of the blade 120 can taper from the leading edge 126 toward the trailing edge 128. The thickness of the blade 120 can taper such that the pressure surface 130 and the suction surface 132 intersect at a point at the trailing edge 128 of the blade 120.

[0077] In some embodiments, the blade 120 may have a constant thickness from the blade root 122 to the blade tip 124. In other embodiments, the thickness of the blade 120 may be variable. In some embodiments, the thickness of the blade 120 may be greater at the blade tip 124 than at the hub 110. The tangential velocity of the blade 120 increases from the blade root 122 to the blade tip 124. Therefore, the orthogonal component of the impact velocity of the blade 120 when encountering a fish near the blade tip 124 may be greater than the orthogonal component of the impact velocity of the blade 120 when encountering a fish near the blade root 122. To reduce the risk of death for the fish 300 in the region where it is most likely to encounter high impact velocities, the blade may have a thick leading edge and additionally or alternatively a sloping leading edge, as will be discussed.

[0078] For example, such as Figure 4 As shown, the blade 120 of the turbine runner 100 may have a leading edge 126, which may be inclined at an angle θ at one or more locations (e.g., locations t, m, h) along the leading edge 126. (A curve can be drawn from the hub to the blade tip along the apex of the blade's stagnant region, thus defining the blade's leading edge. A tangent drawn at any point along this curve can be measured relative to a cylindrical surface coaxial with and intersecting the turbine runner's axis of rotation at that point. The inclination angle is measured between the tangent and a vector located on the cylindrical surface that is perpendicular to the leading edge and coincides with the intersection point of the leading edge.) Fish mortality rate is the normal component of the impact velocity during the impact. w N The function of . Therefore, reducing the normal component of the impact velocity during impact.w N This leads to a reduction in fish mortality. Therefore, compared to a blunt blade with an angle θ other than 90 degrees at the leading edge, fish mortality is reduced.

[0079] In some embodiments, the leading edge 126 may be tilted at a position at an angle θ of about 25 degrees to about 45 degrees. In some embodiments, the leading edge 126 may be tilted at a position at an angle θ of about 30 degrees.

[0080] In some embodiments, the leading edge 126 may be angled at the blade tip 124. As previously described, the impact velocity increases from the blade root 122 of the blade 120 to the blade tip 124 of the blade 120, such that the blade tip 124 of the blade 120 has the maximum impact velocity. Therefore, providing an angle θ θ for the leading edge 126 at the blade tip 124 of the blade 122 can reduce the mortality rate of fish 300 that would otherwise be more likely to suffer a fatal impact. For example, providing an angled leading edge 126 at the blade tip 124 also helps to prevent debris from accumulating or accumulating at the blade tip 124.

[0081] In some implementations, the leading edge 126 may be tilted at a position between the leaf root 122 and the leaf tip 124. For the same reasons discussed above regarding providing a tilt angle to the leading edge 126 at the leaf tip 124, providing a tilt angle θ to the leading edge 126 in the region between the leaf root 122 and the leaf tip 124 may reduce the mortality rate of fish 300 that may be relatively likely to suffer a fatal impact.

[0082] In some implementations, for example, Figure 4 As shown, the tilt angle θ at the tip 124 of the blade 922 can be smaller than the tilt angle θ at the root 120 and / or at the position between the root 122 and the tip 124.

[0083] In some embodiments, the leading edge 126 may be angled at the blade root 122. For example, the angle of inclination of the leading edge 126 of the blade 120 at the blade root 122 may be from about 10 degrees to about 90 degrees, such as from about 25 degrees to about 45 degrees. In addition to improving the survival rate of fish 300 that impact the blade 120 at the blade root 122, providing an angled leading edge 126 at the blade root 122 may also, for example, help prevent debris from accumulating or gathering at the junction of the blade root 122 of the blade 120 and the hub 110.

[0084] In some implementations, for example, Figure 4 As shown, the leading edge 126 of the blade 120 can be tilted, making the leading edge 126 arc-shaped. In other embodiments, the leading edge 126 can have a C-shape, a semi-circular shape, a parabolic shape, a conical shape, a saddle shape, or some other shape.

[0085] In some implementations, for example, Figure 4 As shown, the leading edge 126 of the blade 120 can be bent toward the trailing edge 128 of the blade 120 near the hub 110, giving the leading edge 126 a concave shape. For example, this can allow for a smaller angle at the blade tip 124 while minimizing the cantilevered blade tip.

[0086] In some embodiments, the leading edge 126 of the blade 120 at the leaf root 122 may be tilted at a first angle θ, and the leading edge 126 of the blade 120 at the leaf tip 124 may be tilted at the same angle θ.

[0087] In some embodiments, the root 122 of the leading edge 126 of the blade 120 is positioned along the radial axis 160 of the runner 100, and the tip 124 of the leading edge 126 extends beyond the radial axis 160 in the circumferential direction 170. Therefore, the leading edge 126 of the blade 120 can be cantilevered.

[0088] Because the blade tip 124 extends far beyond the radial axis 160 along the circumferential direction 170 at the leading edge 126, a smaller angle can be achieved. This can result in a larger normal component of the impact velocity during impact. w N However, as the angle continues to decrease, the structural stiffness of the blade may also decrease. Maintaining the minimum structural stiffness requirements for the blade could lead to increased manufacturing costs. For example, structural stiffness may be required to keep the blade tip 124 of blade 120 within the tight tolerances of the turbine casing.

[0089] In some embodiments, the root 122 of the leading edge 126 of the blade 120 and the tip 124 of the leading edge 126 of the blade 120 can both be positioned along the radial axis 160.

[0090] For example, such as Figure 6 As shown, when viewed along an axis perpendicular to the shaft axis 150 (i.e., from one side of the rotor 100), the blades 120 of the rotor 100 can have an arc-shaped leading edge 126. For example, as Figure 6 As shown, when the blade 120 is viewed from one side of the rotor 100, the leading edge 126 of the blade 120 (from the blade root 122 to the blade tip 124) can bend away from the upstream end of the rotor 100 and then bend back toward the upstream end of the rotor 100.

[0091] In some implementations, the cross-section at the blade root can have a much greater thickness near the leading edge compared to any other cross-section taken across the blade at any other radius. Its size and location allow the blade surface to intersect the hub at an obtuse angle around the leading edge. This is important for achieving a uniform pressure distribution on the blade's suction surface (i.e., the downstream surface). Conversely, if the downstream blade surface near the leading edge intersects the spherical hub at a near-perpendicular or acute angle, a localized low-pressure region is likely to form near the intersection of the blade surface and the hub, resulting in an unnecessarily reduced cavitation margin.

[0092] In some implementations, for example, Figure 4 and Figure 6 As shown, the blades 120 of the rotor 100 may have an arcuate leading edge 126 when viewed along the shaft axis 150 and when viewed along an axis perpendicular to the shaft axis 150 (i.e., from one side of the rotor 100). However, in some embodiments, the leading edge 126 may be arcuate only when viewed along the shaft axis 150 or only when viewed along an axis perpendicular to the shaft axis 150.

[0093] For example, such as Figure 6 As shown, the blades 120 of the runner 100 may have a cambered leading edge 126. That is, the stacking line along the leading edge of the blade may have a non-zero angle relative to the radial line at the intersection with the end wall. In some embodiments, the blade may have a negatively cambered leading edge, meaning that the dihedral angle between the blade suction surface and the end wall is acute. In some embodiments, the blade may have a positively cambered leading edge, meaning that the dihedral angle between the blade pressure surface and the end wall is acute. In some embodiments, the dihedral angle between the blade pressure wall and the hub may be different from the dihedral angle between the blade pressure wall and the housing. In some examples, the leading edge 126 has a camber of about -25 degrees to (90 to 75) degrees at the hub and about -15 degrees to (90 to 75) degrees at the tip. The blade may have various offset angles, where the offset angle refers to the angle between the chord line of the blade and the axial flow direction.

[0094] For example, in some implementation schemes, such as Figure 6 and Figure 18 As shown, the trailing edge 128 can have an S-shape. The first portion 133 of the trailing edge can be concave, and the second portion 135 of the trailing edge (e.g., the portion of the trailing edge positioned further from the hub than the first portion) can be convex. This can, for example, facilitate an ideal distribution of pressure on the blade 120 and can help to create an ideal distribution of fluid velocity leaving the impeller and entering the guide tube or diffuser.

[0095] In some implementations, for example, Figure 6 As shown, when viewed along the axis, the trailing edge 128 can have a similar arcuate shape to the leading edge. This allows the surface area of ​​the blades to be maximized, which may be important for achieving cavitation-free operation. Fish-safe runners can use fewer blades compared to conventional designs. For example, a conventional Kaplan turbine operating at a 10-meter head and positioned 3 meters above the tailwater (i.e., drawing 3 meters of suction) can use 5 blades. Fish-safe runners with thicker blades can be designed instead of conventional runners without altering the conventional water passages, but fish-safe runners can benefit from a reduced number of blades, such as down to 4 blades, to allow the same flow rate and power output as conventional runners. It may be necessary to make each of the remaining blades have a larger surface area than a conventional runner to achieve a similar pressure distribution. To achieve the necessary surface area, the trailing edge can intersect the discharge ring surface and the hub at a steep angle. In some embodiments, the trailing edge intersects the discharge ring at an angle between 5 and 110 degrees (e.g., between 10 and 45 degrees).

[0096] A cross-section of the leaf blade 120 can be taken at the leaf root 122, at the leaf tip 124, or between the leaf root 122 and the leaf tip 124. Each cross-section can have a chord length L measured along a straight line from the leading edge 126 to the trailing edge 128. C In some implementations, the chord length L at the leaf tip 124 is... C The chord length L at leaf root 122 C Longer. For example, in some implementations, the chord length L at the leaf tip 124 is... C The chord length L at leaf root 122 C It is about 1.6 times to about 2.5 times longer.

[0097] In some implementations, the chord length L at the leaf tip 124 C With the diameter D of the wheel R The ratio (i.e., L) C,t / D R It can be less than about 0.9.

[0098] By providing an inclined leading edge 126, the orthogonal component of the impact velocity is effectively reduced, allowing the rotor 100 to rotate at higher speeds to improve its power-to-speed ratio and economic competitiveness while ensuring the safe passage of fish. In some embodiments, the rotor 100 is configured to rotate such that the orthogonal component of the impact velocity is about 7 m / s or less to allow the safe passage of fish (e.g., salmon). In some embodiments, the rotor 100 is configured to rotate such that the orthogonal component of the impact velocity is about 11 m / s or less to allow the safe passage of fish (e.g., eels). In some embodiments, even with higher orthogonal impact velocities, up to about 20 m / s, the survival rate of aquatic organisms is very high, such as a survival rate exceeding 98%. In some embodiments, the rotor has a tangential velocity of up to 20 m / s to 40 m / s at the blade tip while still achieving a very high survival rate of aquatic organisms.

[0099] The impeller 100 and / or blade 120 can be made of any suitable material and can be formed by any suitable process. In some embodiments, the impeller 100 and / or blade 120 are made of molded carbon fiber / glass fiber and resin. In such embodiments, the blade 120 may include a core composed of lightweight foam. In some embodiments, the impeller 100 is composed of metal (such as bronze, stainless steel, etc.) and may be formed from a casting (including hollow castings) machined to its final shape. In some embodiments, the impeller 100 and / or blade 120 are hollow. In some embodiments, the impeller 100 is composed of composite materials and is produced via conventional composite construction methods. For example, the impeller 100 may have a sandwich composite construction, or may include shear webs within the structure, or may be made as a monolithic construction with thick walls. In some embodiments, the impeller 100 is composed of an elastomer or polymer, with reinforcements distributed locally or integrally within it.

[0100] Blade 120 may have a hybrid construction. In some embodiments, the leading edge 126 of blade 120 is protected. Leading edge 126 may include a coating. Leading edge 126 may be metallic. In some embodiments, blade tip 124 is molded with a thick ablation material layer, such that blade tip 124 can be worn down to the inner diameter of the turbine casing (e.g., as shown in the image). Figures 14 to 16 (As shown). One or more of the blades 120 may include an anti-cavitation lip. The anti-cavitation lip may include a lip extending from the blade tip 124 along the length of the blade tip 124 between the leading edge 126 and the trailing edge 128. The anti-cavitation lip may be in the form of a flat plate. The anti-cavitation lip may help control flow around the blade tip.

[0101] In some implementations, the diameter D of the rotor 100 R It can be at least about 1.5 meters. In some embodiments, the diameter D of the rotor 100 is... R It can range from about 1.5 meters to about 7 meters, such as from about 2 meters to about 5 meters. The diameter can correspond to the spherical diameter measured from the outer radius of the turbine blade.

[0102] Axial length L of rotor 100 R The diameter D of the rotor 100 on the downstream side of the rotor 100 R The ratio can be less than about 0.55, or it can be from about 0.25 to about 0.55. The runner 100 can have an axial tip length L defined as the distance between the tip 124 of the leading edge 126 and the tip 124 of the trailing edge 128. t In some examples, the dimensions of the housing can be determined by the axial tip length L. t Sure Figure 20 The diagram illustrates that the pressure center 1930 and center of mass 1940 of blade 1920 may be offset. For example, the pressure center 1930 may be located closer to the trailing edge 1928 of blade 1920 than the center of mass 1940. The pressure center 1930 may also be located closer to the tip 1924 of blade 1920 than the blade center of mass 1940. In some examples, the trailing edge 1928 is overhanging or extends downstream of the spherical or cylindrical portion of the turbine casing. The blade center of mass 1940 may be near the blade pivot axis 1950. Blade material may be a variable affecting the position of the pressure center 1930 and center of mass 1940 of blade 1920. Other variables may include axial tip length, leading edge thickness, and trailing edge overhang.

[0103] Compared to blades without trailing edge overhangs, blades with trailing edge overhangs can have a larger blade surface area. However, compared to blades without trailing edge overhangs, blades with trailing edge overhangs can distribute more blade weight downstream of the pivot axis, thus putting stress on pivoting. To mitigate the downstream weight distribution problem, blades may be tilted forward and have a thick leading edge to help optimize mass distribution. Figure 20 An example of a component for actuating blade 1920 is shown. However, as those skilled in the art will understand, other components and devices for actuating blades can be used. The actuation mechanism may include an oil-filled hub, an oil-free hub, or directional actuation of each blade.

[0104] As described above, in some embodiments, the runner 100 is integrated into the turbine 200 (e.g., in...). Figures 14 to 16 (As shown in the image). Figures 14 to 16In this embodiment, shaft axis 150 is vertical relative to the ground. However, in other embodiments, shaft axis 150 may be horizontal relative to the ground, or may be at an angle between horizontal and vertical relative to the ground. In some embodiments, the wheel drives the shaft upstream of the wheel. In other embodiments, the wheel drives the shaft downstream of the wheel.

[0105] In some embodiments, turbine 200 may include inlet and outlet elements that are generally known. The inlet element may include, for example, a helical or semi-helical shape. In some embodiments, the inlet of turbine 200 is intended to connect to the outlet of a pressurized pipe, pressure steel pipe, or volute. The outlet element may include, for example, a guide tube. The guide tube may have a cross-sectional area appropriately varied to restore the velocity head. Considering the characteristics of hydroelectric power plants, the guide tube may be straight or have bends, as appropriate.

[0106] During operation, water can flow into turbine 200, and if guide vanes are present, flow through guide vane stages (the pitch of which may be fixed or adjustable depending on the application), flow through runner 100, and flow out to diffuser or guide tube, and from there flow to tailwater or deliver the discharged water to tailwater outlet pipe.

[0107] In some embodiments, turbine 200 operates at a head of at least 1 meter. In some embodiments, turbine 200 operates at a head of at least 10 meters. In some embodiments, turbine 200 operates at a head of at least 20 meters. In some embodiments, turbine 200 operates at a head of at least 30 meters. In some embodiments, turbine 200 operates at a head of at least 40 meters.

[0108] In some implementations, the runner 100 may be incorporated into the turbine 200, and the turbine 200 may be part of a hydroelectric power generation unit comprising a plurality of turbines.

[0109] In some implementations, the runner 100 is retrofitted into an existing turbine or hydroelectric power unit. During retrofitting, it is often important to minimize alterations to existing civil engineering and electrical infrastructure. For example, retrofitting may be subject to stringent constraints such as using an existing generator at a fixed shaft speed, mounting the runner at a predetermined height relative to the tailwater level, and operating it in conjunction with existing intake chambers, runner discharge rings, and guide pipes—all of which severely limit the design scope that can create a runner that is safe for fish.

[0110] Now for reference Figures 21 to 22 The image shows a runner 2100 for a hydraulic turbine. The runner 2100 may have features as described above with respect to the runner 100. For example, the runner 2100 may have blades pivotally connected to a hub.

[0111] Figures 21 to 22 The difference in the wheel 2100 is that it has a non-circular or non-spherical hub 2110. The wheel 2100 may have a pseudo-polygonal hub 2110. The hub 2110 may have a generally spherical shape but have multiple faces 2112. The faces 2112 may not correspond to the spherical shape of the hub 2110. In some examples, the multiple faces may have curved or convex shapes. The faces 2112 may have a spherical shape with a larger radius of curvature relative to the rest of the hub 2110. In other words, the multiple faces 2112 may have a smaller curvature than the rest of the hub 2110 except for the faces 2112. In some examples, the multiple faces 2112 are typically flat or planar. Each face 2112 may have a circular region or perimeter. Figure 21 As shown, the hub 2110 may have a cubic shape with rounded corners. The hub 2110 may have four or more faces 2112, and each face 2112 may have a circular shape. The faces 2112 may be radially spaced around the longitudinal axis of the hub 2110. The faces 2112 may be configured to attach to blades 2120. In some examples, a portion of the blades 2120 attached to the faces 2112 may have a different shape or size relative to the faces 2112. According to some examples, each face 2112 may be flat or planar when viewed at an angle perpendicular to the faces 2112. In some examples, the remainder of the hub 2110, except for the faces 2112, may be rounded. In some examples, the hub 2110 may have four blades 2120, and the root 2122 of each blade 2120 may be attached to the hub 2110 at a face 2112. For each blade of the impeller, the hub may have one face 2112. Some examples may include more than four faces 2112 and more than four blades 2120, such as between six and ten faces and between six and ten blades 2120. Compared to hubs with other shapes, a pseudo-polygonal hub 2110 can produce an increased cross-sectional flow area. For example, Figure 21 The perimeter of a hypothetical spherical hub 2114 is shown in the figure. As can be seen in this example, there may be a space 2116 between the perimeter of the hypothetical spherical hub 2114 and the pseudo-polygonal hub 2110. These spaces 2116 can provide additional flow area, and increasing the cross-sectional flow area may reduce the average flow velocity for a given power output.

[0112] According to some implementation plans, such as Figure 21As shown, the leading edge 2126 of one or more blades 2120 can be tilted forward in the direction of rotation. For example, the blade root 2122 can be positioned at the radial axis 2160 of the rotor 2100, and the blade tip 2124 of the leading edge 2126 can extend beyond the radial axis 2160 in the circumferential direction 2170. The leading edge 2126 can have a concave shape, such as... Figures 21 to 22 As shown.

[0113] The turbine may have a discharge ring 2153, such as Figure 22A As shown. The discharge ring 2153 can be a split discharge ring having two or more segments connected along one or more planes perpendicular to the shaft axis 150. The two or more segments can also be connected along one or more planes parallel to the shaft axis 150. In some examples, two segments are connected along a single plane. In some embodiments, three or more wedge-shaped segments are connected along multiple planes. Among other fastening methods, the segments can be connected via bolt holes 2152. Figure 22A As shown, each segment of the discharge ring 2153 may have a split surface for abutting and connecting the segment with one or more other segments to form the discharge ring 2153.

[0114] Figures 23 to 24 An embodiment of the impeller 2100 is shown, having a trailing edge 2128 extending rearward toward the downstream end 2180 of the hub 2110. In some examples, the leading edge 2126 may not extend forward toward the discharge ring or dome portion 2192 of the housing 2190, while the trailing edge may extend rearward toward the dome portion 2192. The hub 2210 may have an upstream end 2178 and a downstream end 2180. Figure 23 As shown, the downstream end 2180 can be the furthest downstream surface of the hub 2110 in the longitudinal direction 2150. According to some examples, the blade root 2122 of the trailing edge 2128 can extend behind the downstream end 2180 in the longitudinal direction 2150. The distance by which the blade root 2122 extends behind the downstream end 2180 in the longitudinal direction 2150 can define the trailing edge overhang 2182.

[0115] like Figure 24 As shown, the entire trailing edge 2128 can extend rearward toward the downstream end 2180 of the hub 2110. In these examples, a trailing edge tip overhang 2184 may be present in addition to or as an alternative to the trailing edge root overhang 2182. In some embodiments, the trailing edge root overhang 2182 may be larger than the trailing edge tip overhang 2184. In some examples, the root 2122 of the trailing edge 2128 may extend rearward or further downstream relative to the rest of the blade 2120.

[0116] In operation, such as Figures 23 to 24As shown, the turbine runner 2100 can be enclosed by the turbine housing 2190. The housing 2190 may have a discharge ring or a dome portion 2192. In some examples, such as Figure 24 As shown, the dome portion 2192 may surround a portion of the wheel 2100. According to some examples, the rear portion of the dome portion 2192 may be radially aligned with the downstream end 2180 of the hub 2110, that is, aligned along the axis 2130.

[0117] In some embodiments, the trailing edge 2128 of the blade 2120 may extend downstream of the dome portion 2192. In some embodiments, the trailing edge root overhang 2182 and the trailing edge tip overhang 2184 may be measured relative to the rear end 2194 of the dome portion 2192, rather than relative to the downstream end 2180. Figure 23 As shown, in some embodiments, the leaf root 2122 of the trailing edge 2128 may extend rearward toward the dome portion 2192, and the leaf tip 2124 of the trailing edge 2128 may not extend rearward toward the dome portion 2192. In some examples, the leaf tip 2124 may be positioned forward relative to the rear of the dome portion 2192. In other embodiments, such as Figure 24 As shown, both the leaf tip 2124 and leaf root 2122 at the trailing edge can extend over or behind the dome portion 2192. In some examples, the entire trailing edge 2128 can be positioned behind the dome portion 2192.

[0118] Whether measured from the rear of the hub 2110 or from the rear of the dome portion 2192, the impeller 2100 with the trailing edge blade root overhang 2182 can have similar advantages. For example, the trailing edge blade root overhang 2182 increases the chord length compared to a blade without an overhang, thus increasing the surface area of ​​the blade 2120. This increase in surface area can be achieved without increasing the spherical outer diameter of the impeller 2100. Extending the trailing edge 2128 downstream also allows for a longer chord length, which can reduce intake pressure and minimize cavitation.

[0119] according to Figures 24 to 25B In the illustrative embodiment, the cross-section of blade 2120 can be taken at line 25H-25H. The cross-section at line 25H-25H can correspond to the cross-section of blade 2120 taken at the blade root 2122. For example, in Figure 25B The image shows the cross-sectional shapes of the leaf taken at the leaf base, midsection, and leaf tip.

[0120] like Figure 25BAs shown, the cross-section of blade 2120 along line 25H-25H can have varying thickness. The thickness obtained near the trailing edge 2128 can be less than the thickness at the leading edge 2126. First blade root thickness t 1h It can be more than the thickness t of the second leaf root 2h Positioned closer to the trailing edge 2128, and with a first leaf root thickness t 1h It can be less than the thickness t of the second leaf root. 2h The thickness t of the first leaf root 1h The ratio of the length of the chord (t) h The chord length (t) can be between approximately 0.03 and 0.1 at the leaf base, between approximately 0.01 and 0.05 at the midspan or midline of the leaf blade, and between approximately 0.01 and 0.05 at the leaf tip. Second leaf base thickness t 2h At the leaf base, it can be between approximately 0.1 and 0.2; at the midspan or midline of the leaf blade 2120, it can be between approximately 0.08 and 0.16; and at the leaf tip, it can be between approximately 0.05 and 0.11.

[0121] According to some examples, the surface curvature of the cross-section at 25H-25H can have a first shape 2136 and a second shape 2138. The first shape 2136 can be rearward relative to the second shape 2138, and the first shape 2136 and the second shape 2138 can be defined by a surface 2132 or a surface 2134. The first shape 2138 can be positioned closer to the trailing edge 2128 relative to the second shape 2136, and the second shape 2138 can be positioned closer to the leading edge 2126. In some embodiments, the minimum thickness of the second shape 2138 can be greater than the maximum thickness of the first shape 2136. In other examples, the maximum thickness of the second shape 2138 can be greater than the maximum thickness of the first shape 2136.

[0122] In some implementations, the first shape 2136 can be convex, and the second shape can be concave. In some examples, the leading edge 2126 can have a concave shape, which may correspond to the thick leading edge 2126 of the blade 2120. In some examples, the leading edge 2126 can have an arcuate shape when viewed along an axis perpendicular to the axis of rotation of the impeller 2100. A thick leading edge 2126 can promote fish safety. Conversely, the trailing edge 2128 can be narrower relative to the leading edge 2126. In some examples, the trailing edge 2128 can taper. A narrow trailing edge 2128 can improve the efficiency of the impeller 2100 compared to an impeller without a narrow trailing edge. In some examples, the thickness distribution at the intersection of the blade root 2122 and the hub 2110 may be steep.

[0123] In some examples, the blade root 2122 of blade 2120 extends further downstream than the rest of the trailing edge 2128 compared to a conventional blade, and the steep positive slope of the thickness distribution at the intersection of the blade root 2122 and the hub 2110 can lead to improved pressure distribution. For example, this can be achieved in... Figure 27 The diagram illustrates that the downstream surface 2118 near the blade root 2122 is curved away from the radial line 2160. For example, compared to a conventional blade, pressure can be distributed more evenly across the surface of blade 2120. Optimal pressure distribution can help reduce barotrauma to entrained fish. Barotrauma refers to damage caused by changes in air or water pressure. Optimal pressure distribution can reduce other damage caused by excessive or uneven local pressure distribution.

[0124] exist Figures 26 to 27 In an illustrative example, the impeller 2100 may include blades 2120 having a trailing edge 2128 that is arched or curved in an upstream direction. In other words, a portion of the trailing edge 2128 between the blade tip 2124 and the blade root 2122 may be longitudinally positioned upstream relative to the trailing edge 2128 at the blade tip 2124 and the blade root 2122. An imaginary line 2129 may be drawn from the blade tip 2124 to the blade root 2122 of the trailing edge 2128. Except for the blade tip 2124 and the blade root 2122, the trailing edge 2128 may be positioned upstream relative to the imaginary line 2129. In some examples, a portion of the trailing edge 2128 may be positioned upstream relative to the imaginary line 2129. According to some embodiments, the entire trailing edge 2128, except for the blade tip 2124 and the blade root 2122, may be positioned upstream relative to the imaginary line 2129.

[0125] When blade 2120 deflects toward or near the closed position, the upstream arching of the trailing edge 2128 helps mitigate the risk of cavitation on the surface downstream of the leading edge 2126 at the blade tip 2124. In other words, when blade 2120 deflects toward the closed position, the upstream arching of the trailing edge 2128 can create a gap between adjacent blades 2120, thereby mitigating the risk of cavitation. The upstream arching of the trailing edge 2128 can also mitigate the high velocity and low pressure near the trailing edge 2128.

[0126] Figure 28This is a graph 2800 showing a comparison of the normalized chord length distribution of the blades of this disclosure 2842 with that of conventional Kaplan blades 2844 and 2846. The x-axis 2810 is defined as the ratio of the blade radius to the maximum radius of the blade (radius / maximum radius). This ratio is 1 at the blade tip because the maximum radius is located at the blade tip. The y-axis represents the ratio of the chord length to the maximum chord length (chord length / maximum chord length). The maximum chord length is 1 at the blade tip because the turbine blades of this disclosure 2842 have a maximum chord length at the blade tip. Each blade has two sets of lines, the upper set 2840 corresponding to the leading edge or upstream region of each blade, and the lower set 2830 corresponding to the trailing edge or downstream region of each blade. This graph shows that, among other features, unlike conventional blades that curl back towards the longitudinal axis of the turbine, the turbine blades of this disclosure are tilted forward or tip-tilted.

[0127] It should be understood that the Detailed Description section, rather than the Summary and Abstract section, is intended to interpret the claims. The Summary and Abstract section may set forth one or more, but not all, exemplary embodiments of the invention as conceived by the inventors, and therefore is not intended to limit the invention and the appended claims in any way.

[0128] The present invention has been described above using functional building blocks that illustrate implementations of specified functions and their relationships. For ease of description, the boundaries of these functional building blocks have been arbitrarily defined herein. Alternative boundaries may be defined, provided that the specified functions and their relationships are appropriately performed.

[0129] The foregoing description of the specific embodiments will fully reveal the general characteristics of the invention, enabling others to readily modify and / or alter such specific embodiments for various applications by applying knowledge of the art, without excessive experimentation and without departing from the general concept of the invention. Therefore, based on the teachings and guidance presented herein, such changes and modifications are intended to be within the meaning and scope of equivalents of the disclosed embodiments. It should be understood that the wording or terminology herein is for descriptive purposes and not for limitation, and that the terminology or terminology of this specification should be interpreted by those skilled in the art based on the teachings and guidance herein.

[0130] The breadth and scope of this invention should not be limited to any of the exemplary embodiments described above, but should be defined solely by the following claims and their equivalents.

[0131] Other embodiments of the present invention can be further illustrated by the following numbered clauses.

[0132] 1. A runner for a hydraulic turbine, the runner comprising: a hub; and a plurality of pivotable blades extending from the hub, each of the plurality of pivotable blades comprising: a blade root located at the hub, a blade tip opposite to the blade root, and a leading edge opposite to the trailing edge, wherein each of the plurality of pivotable blades is pivotable relative to the hub about a respective pivot axis, and wherein for at least one blade, the leading edge at the blade root is positioned along a radial axis of the runner, and the leading edge at the blade tip cantilevered beyond the radial axis in a circumferential direction of the runner; wherein the thickness of the leading edge is greater than the thickness of the trailing edge.

[0133] 2. The impeller as described in Clause 1, wherein for at least one of the plurality of pivotable blades, the trailing edge is disposed downstream of the downstream end of the hub.

[0134] 3. The impeller as described in Clause 2, wherein the blade tip of the trailing edge is disposed downstream of the downstream end of the hub.

[0135] 4. The impeller as described in Clause 2, wherein the blade root of the trailing edge extends further downstream than the remainder of the trailing edge.

[0136] 5. The impeller as described in any one of clauses 1 to 4, wherein at least one of the plurality of pivotable blades has a cross section at the blade root, the surface curvature of the cross section having a first shape and a second shape, optionally wherein the first shape is concave and the second shape is convex.

[0137] 6. The impeller as described in Clause 5, wherein the maximum blade root thickness of the second shape is greater than the maximum blade root thickness of the first shape, and the first shape is positioned closer to the trailing edge than the second shape.

[0138] 7. The wheel as described in any one of clauses 1 to 6, wherein the hub comprises a plurality of faces, the plurality of faces being planar.

[0139] 8. The wheel as described in Clause 7, wherein one of the plurality of faces has a circular shape.

[0140] 9. The impeller as described in Clause 7 or 8, wherein each of the plurality of faces is coupled to the blade root of the pivotable blade of the plurality of pivotable blades.

[0141] 10. The impeller as described in any one of clauses 1 to 9, wherein the trailing edge of the pivoting blade of the plurality of pivoting blades is arched upstream between the blade tip and the blade root of the pivoting blade.

[0142] 11. The runner as described in any one of clauses 1 to 10, wherein the thickness of the leading edge of the pivoting blade in the plurality of pivoting blades is greater than about 100 mm.

[0143] 12. A runner for a hydraulic turbine, the runner comprising: a hub; and a plurality of pivotable blades extending from the hub, each of the plurality of pivotable blades comprising: a blade root located at the hub, a blade tip opposite to the blade root, and a leading edge opposite to the trailing edge, wherein each of the plurality of pivotable blades is pivotable relative to the hub about a respective pivot axis, and wherein for at least one blade, the leading edge is arcuate when viewed along an axis perpendicular to the axial axis of the runner; wherein at least one of the plurality of pivotable blades has a cross section at the hub, the surface of the cross section having a first shape and a second shape, wherein the first shape is concave and the second shape is convex.

[0144] 13. The wheel as described in Clause 12, wherein the hub is a cube shape having rounded edges and one or more faces having a circular shape, the faces being radially spaced about the longitudinal axis of the hub.

[0145] 14. The impeller as described in Clause 12 or 13, wherein the blade root of the trailing edge extends further downstream than the remainder of the trailing edge.

[0146] 15. A turbine comprising: a housing defining an inlet and an outlet for fluid flow; and a runner positioned within the housing, the runner including: a hub; and a plurality of pivotable blades extending from the hub, each of the plurality of pivotable blades including: a blade root located at the hub; a blade tip opposite to the blade root; and a leading edge opposite to the trailing edge, wherein each of the plurality of pivotable blades is pivotable relative to the hub about a respective pivot axis, and wherein for at least one blade, the leading edge at the blade root is positioned along a radial axis of the runner, and the leading edge at the blade tip cantilevered beyond the radial axis in a circumferential direction of the runner; wherein at least one of the plurality of pivotable blades has a cross section at the hub, the surface of the cross section having a first shape positioned closer to the leading edge than a second shape, wherein the first shape is concave and the second shape is convex, and the thickness of the leading edge is greater than the thickness of the trailing edge.

[0147] 16. The turbine as described in Clause 15, wherein the hub is a cube shape having rounded edges and one or more faces.

[0148] 17. The turbine as described in Clause 16, wherein each of the one or more faces has a circular shape.

[0149] 18. The turbine as described in any one of Clauses 15 or 17, wherein the surfaces are radially spaced apart about the longitudinal axis of the hub.

[0150] 19. The turbine of any one of clauses 15 to 18, wherein the blade root, the blade tip, or both of the trailing edge and the blade root extend toward the rear of the downstream end of the hub.

[0151] 20. The turbine of any one of clauses 15 to 19, wherein the trailing edge of the pivoting blade of the plurality of pivoting blades is arched upstream between the blade tip and the blade root.

Claims

1. A runner for a hydraulic turbine, the runner comprising: Wheel hub; as well as A plurality of pivotable blades extending from the hub, each of the plurality of pivotable blades comprising: The blade root located at the hub, The leaf tip, opposite to the leaf root, and Past life Each of the plurality of pivotable blades is capable of pivoting relative to the hub about its respective pivot axis. The thickness T of the leading edge LE With respect to the diameter D of the wheel R The ratio is in the range of approximately 0.03 to approximately 0.35, and In one or more blades, the leading edge at the blade root is positioned along the radial axis of the rotor, and the leading edge at the blade tip cantilevered out of the radial axis in the circumferential direction of the rotor.

2. The impeller as claimed in claim 1, wherein the ratio of the axial length of the impeller to the diameter of the impeller is less than about 0.

55.

3. The impeller of claim 1, wherein the ratio of the chord length at the tip of each pivotable blade to the diameter of the impeller is less than about 0.

9.

4. The wheel as claimed in claim 1, wherein each pivot axis is at an angle between about 8 degrees and about 155 degrees relative to the axis of rotation of the wheel.

5. The runner as claimed in claim 1, wherein during the rotation of the blades from the maximum pitch to the minimum pitch, the outer surface of the hub swept by the blade root of each pivotable blade is spherical.

6. The runner of claim 1, wherein during the rotation of the pivotable blades from the maximum pitch to the minimum pitch, the root of each pivotable blade conforms to the shape of the outer surface of the hub. Within the pivoting range of the pivotable blade from the maximum pitch to the minimum pitch, the tip of each pivotable blade has a generally spherical swept shape.

7. The impeller of claim 1, wherein the thickness of the leading edge of each pivotable blade is between about 100 mm and about 700 mm.

8. The impeller of claim 1, wherein a portion of the leading edge at the tip of each pivotable blade is inclined relative to the radial axis of the impeller at an angle between about 20 degrees and about 90 degrees.

9. The impeller of claim 1, wherein, when viewed along an axis perpendicular to the axial axis of the impeller, the leading edge of each pivotable blade is arc-shaped, and When viewed along the axis perpendicular to the axis of the rotor, the leading edge of each pivotable blade bends at the blade root away from the upstream end of the rotor and bends back toward the upstream end of the rotor toward the blade tip.

10. The wheel of claim 1, wherein the radius of curvature of one or more surfaces is greater than the radius of curvature of the rounded edge of the hub.

11. The wheel of claim 1, wherein the first portion of the trailing edge is concave, the second portion of the trailing edge is convex, and the first portion of the trailing edge is positioned closer to the hub than the second portion of the trailing edge.

12. A turbine, the turbine comprising: A housing that defines an inlet and an outlet for fluid flow; as well as A runner for a hydraulic turbine, the runner comprising: Wheel hubs; and A plurality of pivotable blades extending from the hub, each of the plurality of pivotable blades comprising: The blade root located at the hub, The leaf tip, opposite to the leaf root, and The anterior edge opposite to the posterior edge, Each of the plurality of pivotable blades is capable of pivoting relative to the hub about its respective pivot axis. The thickness T of the leading edge LE With respect to the diameter D of the wheel R The ratio is in the range of approximately 0.03 to approximately 0.35, and In one or more blades, the leading edge at the blade root is positioned along the radial axis of the rotor, and the leading edge at the blade tip cantilevered out of the radial axis in the circumferential direction of the rotor.

13. The turbine of claim 12, wherein during the rotation of the blades from the maximum pitch to the minimum pitch, the tip of each pivotable blade conforms to the shape of the discharge ring of the housing, and During the rotation of the pivotable blades from the maximum pitch to the minimum pitch, the inner surface of the discharge ring of the housing swept by the blade tip of each pivotable blade is spherical.

14. The turbine of claim 12, wherein the discharge ring of the housing has a removable section configured to be removably assembled from the outside or inside of the turbine, and wherein the discharge ring of the housing is split.

15. The turbine of claim 12, wherein the blade root of the trailing edge extends further downstream than the remainder of the trailing edge.

16. A runner for a hydraulic turbine, the runner comprising: Wheel hub; as well as A plurality of pivotable blades extending from the hub, each of the plurality of pivotable blades comprising: The blade root located at the hub, The leaf tip, opposite to the leaf root, and The anterior edge opposite to the posterior edge, Each of the plurality of pivotable blades is pivotable relative to the hub about its respective pivot axis, and wherein for at least one blade, the leading edge at the blade root is positioned along the radial axis of the wheel, and the leading edge at the blade tip cantilevered beyond the radial axis in the circumferential direction of the wheel. In the meridional section, the trailing edge at the leaf root of the blade is positioned further downstream than the trailing edge at the leaf tip of the blade.

17. The impeller of claim 16, wherein for at least one of the plurality of pivotable blades, the trailing edge extends downstream of the downstream end of the hub.

18. The impeller of claim 16, wherein at least one of the plurality of pivotable blades has a cross section at the blade root, the surface curvature of the cross section having a first shape and a second shape, wherein the first shape is concave and the second shape is convex.

19. The wheel of claim 16, wherein the hub comprises a plurality of planar surfaces, the surfaces being radially spaced about a longitudinal axis of the hub.

20. The impeller of claim 16, wherein the trailing edge of the pivoting blade of the plurality of pivoting blades arches upstream between the blade tip and the blade root of the pivoting blade.

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