Hydraulic turbine impeller

Abstract

The impeller for the hydraulic turbine is configured to reduce fish mortality. The impeller includes a hub and a plurality of blades extending from the hub. Each blade includes a root connected to the hub and a tip opposite the root. Each blade further includes a leading edge opposite the trailing edge.

Description

Technical Field

[0001] Cross-Reference to Related Applications This application claims the priority benefit of U.S. Provisional Patent Application No. 63 / 536,264 filed on September 1, 2023, which is hereby incorporated by reference in its entirety into the present specification.

[0002] The present invention relates to a turbine impeller for hydroelectric power generation. Specifically, the present invention relates to a turbine impeller configured to facilitate safe downstream passage of fish through the turbine.

Background Art

[0003] There is high demand for hydroelectric power plants with low environmental impact. To reduce environmental impact, it is desirable for hydroelectric power plants to minimize the impact on fish and other aquatic wildlife, for example by not harming fish and not obstructing the movement or migration of fish. It is also desirable to construct hydroelectric power plants that have high efficiency and relatively low costs for installation, operation, and maintenance. In addition, it may be desirable to retrofit new turbines to existing hydroelectric power plants to reduce environmental impact and / or improve efficiency.

[0004] Accordingly, there is a continuing need in the art for a turbine that allows fish to pass downstream safely through the turbine, has high efficiency, has relatively low costs for installation, operation, and maintenance, and can be used in various applications including retrofitting.

Summary of the Invention

[0005] As discussed herein, a hydraulic turbine impeller may include a hub and a plurality of blades extending from the hub. Each of the plurality of blades may include a root located in the hub, a tip opposite the root, a leading edge, and a trailing edge opposite the leading edge. The impeller may be configured to rotate about an axis of rotation. Each of the plurality of blades may have a leading-edge midpoint along the leading edge of the blade and a trailing-edge midpoint along the trailing edge of the blade. The surface swept from a circle intersecting the leading-edge midpoint of the blade to a circle intersecting the trailing-edge midpoint of the blade may have a frustoconical shape. The mean diagonal angle α between the lateral surface of the frustoconical shape and the axis parallel to the axis of rotation of the impeller is the mean diagonal angle between them. m This can be defined as follows: At least one blade has a ratio of T, which is the ratio of the leading edge thickness to the diameter of the impeller downstream of the impeller, greater than approximately 0.03. LE / D R This may include: For at least one blade, the leading edge at the root can be positioned along the radial axis of the impeller, and the leading edge at the tip can be supported by a cantilever across the radial axis in the circumferential direction of the impeller. The maximum leading edge thickness of at least one blade may be at least about 50 mm. The maximum leading edge thickness of at least one blade may be at least about 100 mm. The maximum leading edge thickness of at least one blade may be at least about 200 mm. Average diagonal angle α m The mean diagonal angle α can be greater than 0 degrees and less than 90 degrees. m This can be between approximately 2 and 45 degrees. (Mean diagonal angle α) mThe angle can be between approximately 20 and 35 degrees. The impeller may include an outer rim connecting the blade tips around the circumference of the impeller. The leading edge thickness of at least one blade at the blade tip may be greater than the leading edge thickness at the blade root. Multiple blades may include three or more blades. The leading edge of at least one blade may be saddle-shaped. A portion of the leading edge at the blade tip of at least one blade may be inclined forward in the direction of blade rotation. The portion of the leading edge at the blade tip may be inclined at an angle in the range of approximately 20 to 90 degrees. The portion of the leading edge at the blade tip may be inclined at an angle in the range of approximately 25 to 45 degrees. The impeller may be located within a turbine housing having an inlet and outlet for the flow of water.

[0006] The accompanying drawings incorporated herein and forming part of the specification illustrate the disclosure and, together with the description herein, serve to illustrate its principles and enable those skilled in the art to manufacture and use it. [Brief explanation of the drawing]

[0007] [Figure 1A] This is a perspective view of a hydraulic turbine impeller according to one embodiment. [Figure 1B] Figure 1A is a side view of the impeller. [Figure 1C] Figure 1A shows the upstream view of the impeller. [Figure 2A] This is a perspective view of a hydraulic turbine impeller according to one embodiment. [Figure 2B] Figure 2A is a side view of the impeller. [Figure 2C] Figure 2A shows the upstream view of the impeller. [Figure 3A] This is a perspective view of a hydraulic turbine impeller according to one embodiment. [Figure 3B] Figure 3A is a side view of the impeller. [Figure 3C] Figure 3A shows the upstream view of the impeller. [Figure 4A]This is a perspective view of a hydraulic turbine impeller according to one embodiment. [Figure 4B] Figure 3A is a side view of the impeller. [Figure 4C] Figure 3A shows the upstream view of the impeller. [Figure 5A] This is a perspective view of a hydraulic turbine impeller according to one embodiment. [Figure 5B] Figure 5A shows the upstream view of the impeller. [Figure 6A] This is a perspective view of a hydraulic turbine impeller according to one embodiment. [Figure 6B] Figure 6A shows the upstream view of the impeller. [Figure 7A] This is a perspective view of a hydraulic turbine impeller according to one embodiment. [Figure 7B] This is a perspective view of a hydraulic turbine impeller according to one embodiment. [Figure 8A] This is a side view of a hydraulic turbine impeller according to one embodiment. [Figure 8B] This is a cross-sectional view of the impeller blades taken along line EE, as shown in Figure 8A. [Figure 8C] Figure 8A is an axial cross-sectional view of the impeller blades. [Figure 9A] This is a side view of a hydraulic turbine impeller according to one embodiment. [Figure 9B] Figure 9A shows a cross-sectional view taken along the line FF of the impeller blade. [Figure 9C] Figure 9A is an axial cross-sectional view of the impeller blades. [Figure 10A] This is a side view of a hydraulic turbine impeller according to one embodiment. [Figure 10B] This is a cross-sectional view of the impeller blades taken along line GG in Figure 10A. [Figure 10C] Figure 10A is an axial cross-sectional view of the impeller blades. [Modes for carrying out the invention]

[0008] In the embodiments for carrying out the following inventions, many specific details are given in order to provide a complete understanding of the embodiments of this disclosure. However, it will also be apparent to those skilled in the art that embodiments, including structures, systems, and methods, can be practiced without such specific details. The descriptions and expressions herein are common means used by those skilled in the art to communicate their work to others skilled in the art in the most effective way. In other examples, well-known methods, procedures, components, and circuits are not described in detail in order to avoid unnecessarily obscuring the aspects of the disclosure.

[0009] References to "one embodiment," "an embodiment," or "an exemplary embodiment" indicate that the described embodiment may include certain features, structures, or characteristics, but not all embodiments necessarily include those features, structures, or characteristics. Furthermore, such wording does not necessarily refer to the same embodiment. Moreover, when certain features, structures, or characteristics are described in relation to an embodiment, achieving such features, structures, or characteristics in relation to other embodiments is considered to be within the knowledge of those skilled in the art, whether explicitly stated or not.

[0010] As used herein, the terms “about” or “approximately” may mean a range of + / - 5% of the stated quantity or value.

[0011] The following examples are illustrative and not limiting to the disclosure. Other suitable modifications and adaptations of various conditions and parameters are generally accepted in the art and will be apparent to those skilled in the art as being within the spirit and scope of the disclosure.

[0012] Modern hydroelectric power plants often have to meet stringent standards for environmental sustainability. Hydroelectric plants that frequently use impellers that are not safe for fish or other aquatic life to pass downstream need to have systems in place to prevent fish from entering the turbine, or otherwise need to shut down the turbine during the fish migration period. A typical fish exclusion system may include a shield constructed from bars with very small transparent gaps (e.g., 10mm or 19mm bar spacing). Such systems are expensive to construct, difficult to keep clean, and when installed in existing hydroelectric facilities, exclusion shields can result in significant additional energy losses due to the loss of hydrohead. (Approximately 75-100m) 3 While fish-deterrent shields are generally considered impractical to install at flow rates exceeding certain limits such as / s, turbines operating at such high flow rates can be just as dangerous to captured fish as smaller turbines.

[0013] Hydroelectric power plants operating at heads of approximately 60 meters or less often disrupt natural ecosystems, particularly by hindering the upstream and downstream movement of fish and other aquatic life. However, the relatively high availability of such installation sites makes hydroelectric development in this range still desirable. Applications at medium heads (e.g., heads exceeding 30 meters) are particularly desirable because the power density at these sites is relatively higher compared to low-head sites.

[0014] The majority of U.S. hydroelectric power capacity resides in plants with a head of less than 40 meters. Most existing hydroelectric facilities in the U.S. and Europe were first constructed before 1975. Typically, hydroelectric turbines require significant maintenance every 25 to 50 years. Therefore, there is a significant need today for the repair or replacement of hydroelectric turbine impellers. Installing replacement impellers that allow fish to pass downstream safely, while maintaining high efficiency and compatibility with the existing hydroelectric plant's civil and electrical infrastructure, represents a significant economic benefit for hydroelectric plant owners.

[0015] Some embodiments described in the present specification provide an impeller for a hydraulic turbine for use in high head, medium head, and low head applications, enabling safe downstream passage of fish through a turbine with an integrated impeller. The embodiments described in the present specification also achieve high efficiency and have relatively low installation, operation, and maintenance costs. Some embodiments described in the present specification can be used in a wide range of applications, including retrofitting installations.

[0016] In some embodiments, the impeller includes a plurality of blades. The plurality of blades may be fixed to a hub. Each of the plurality of blades has a leading edge midpoint along the leading edge of the blade and a trailing edge midpoint along the trailing edge of the blade. Each of the plurality of blades has a centerline defined as an intermediate portion between the root and the tip of the blade. For example, the centerline may intersect the midpoint between the root and the tip of the leading edge and the midpoint between the root and the tip of the trailing edge. A surface swept from a circle intersecting the leading edge midpoint of the impeller blade to a circle intersecting the trailing edge midpoint of the impeller blade may have a frustoconical shape.

[0017] In some embodiments, a frustoconical lateral surface and an axis parallel to the rotation axis of the impeller have an average oblique angle α between them m defined. In some embodiments, the average oblique angle α m is greater than 0 degrees and less than 90 degrees. In some embodiments, the average oblique angle α m is between about 2 degrees and about 45 degrees. In some embodiments, the average oblique angle α m is between about 20 degrees and about 35 degrees.

[0018] In some embodiments, the impeller is a delia turbine impeller. In some embodiments, the surface swept from a circle intersecting the midpoint of the leading edge of the blades of the delia turbine impeller to a circle intersecting the midpoint of the trailing edge of the blades of the delia turbine impeller may have a frustoconical shape, as described above. In such embodiments, the delia turbine impeller has an average oblique angle α greater than 0 degrees and less than 90 degrees, for example, between about 2 degrees and about 45 degrees, for example, between about 20 degrees and about 35 degrees. m It may have.

[0019] In some embodiments, the impeller is a Francis turbine impeller. In such embodiments, the surface swept from the circle intersecting the leading edge midpoint of the blades of the Francis turbine impeller to the circle intersecting the trailing edge midpoint of the blades may have a frustoconical shape, as described above. In such embodiments, the Francis turbine impeller has an average oblique angle α greater than 0 degrees and less than 90 degrees, for example, between about 2 degrees and about 45 degrees, for example, between about 20 degrees and about 35 degrees. m It may have.

[0020] The impeller 100 may be configured to accept water inflow at an average angle greater than 0 degrees and less than 90 degrees relative to the shaft axis 150. For example, the impeller 100 may be configured to accept water inflow at an average angle between approximately 2 degrees and approximately 75 degrees relative to the shaft axis 150. In some embodiments (for example, for applications with low head), the impeller 100 may be configured to accept water inflow at an average angle between approximately 2 degrees and approximately 15 degrees, for example between approximately 2 degrees and approximately 10 degrees, for example between approximately 2 degrees and approximately 5 degrees. In some embodiments (for example, for applications with high head), the impeller 100 may be configured to accept water inflow at an average angle between approximately 20 degrees and approximately 75 degrees, for example between approximately 20 degrees and approximately 60 degrees, for example between approximately 20 degrees and approximately 45 degrees.

[0021] The impeller 100 may be configured to discharge water in a direction generally parallel to the shaft axis 150. In some embodiments, the water discharged from the impeller may have a complex mixture of velocity components including swirling fluctuations, which can help maintain good pressure recovery within the draft tube.

[0022] In some embodiments, the impeller blades have a thicker leading edge compared to the size of the fish that can pass through the turbine. Fish survival after a blade strike event is sensitive to the ratio of the fish's body length to the turbine blade leading edge thickness and the speed. For example, a blade with a ratio of fish length to blade thickness of less than 1 can allow for approximately 100% fish survival after a blade strike at a strike speed of 7 m / s, and over 90% at a strike speed of 12 m / s. As a result, fish that encounter a blade with a thicker leading edge are more likely to survive the blade impact compared to fish that encounter a blade with a thinner leading edge.

[0023] Furthermore, in some embodiments, the leading edge thickness of the impeller is greater at the tip of the impeller blade than at the hub of the impeller blade. In this way, the protective effect of the thick leading edge is maximized in the region where the blade speed is highest.

[0024] In some embodiments, the leading edge of the impeller blade is inclined forward with respect to the radial axis of the impeller in the direction of rotation, also referred to as a cantilever or forward "lean". As a result, the orthogonal component w of the strike velocity N This decreases, which in turn reduces the mortality rate of fish caused by impact with the blade.

[0025] In some embodiments, the impeller is integrated with the turbine.

[0026] These and other embodiments will be described in further detail below with reference to the figures.

[0027] Figures 1A to 1C show impellers 100 according to several embodiments. Figure 1A shows a perspective view of impeller 100, Figure 1B shows a side view of impeller 100, and Figure 1C shows an upstream view of impeller 100.

[0028] The impeller 100 may be configured to rotate circumferentially 170 about the shaft axis 150 to drive the generator during use. In the embodiment shown in Figure 1C, for example, the circumferential direction 170 is counterclockwise when viewed from the upstream side of the impeller 100. However, in other embodiments, the circumferential direction 170 is clockwise when viewed from the upstream side of the impeller 100.

[0029] The impeller 100 may include a hub 110 and a plurality of blades 120 extending radially from the hub 110.

[0030] The blades 120 can be evenly distributed around the hub 110. In some embodiments, the blades 120 are arranged spirally on the hub 110. In some embodiments, each of the multiple blades 120 of the impeller 100 has the same shape and dimensions.

[0031] In the embodiment shown in Figure 1A, the impeller 100 includes four blades 120. However, in other embodiments, the impeller 100 may include two blades, three blades, five blades, or more than five blades.

[0032] Each blade 120 of the impeller 100 may include a root 122 located in the hub 110, a tip 124 opposite the root 122 and defining the outermost extent of the blade 120, a leading edge 126 in the upstream portion of the impeller 100, a trailing edge 128 in the downstream portion of the impeller 100, an upstream pressure surface 130 of the blade 120, and a downstream suction surface 132 of the blade 120.

[0033] In some embodiments, the shape of the impeller 100 at the blade tip 124 corresponds to the shape of the turbine 200 housing in which the impeller 100 may be used. For example, in some embodiments, the associated turbine housing may have a frustoconical shape that tapers inward from the upstream side to the downstream side of the turbine housing, and the outermost range of the blade tip 124 may have a corresponding taper from the inlet side to the outlet side of the impeller 100. As another example, in some embodiments, the associated turbine housing may have a cylindrical shape, and the outermost range of the blade tip 124 may have a corresponding cylindrical shape.

[0034] In some embodiments, each blade 120 has a leading-edge midpoint along the leading edge 126 of the blade 120 and a trailing-edge midpoint along the trailing edge 128 of the blade 120. As shown in Figure 1B, the surface swept from the circle where the leading-edge midpoint 101 of the impeller blade 120 intersects to the circle where the trailing-edge midpoint 102 of the impeller blade 120 intersects can have a frustoconical shape. The circle where the leading-edge midpoint 101 and the trailing-edge midpoint 102 intersect can be traced by the midpoints 101 and 102 as the impeller 100 rotates around the shaft axis 150 (i.e., as the impeller 100 rotates within the circle).

[0035] As shown in Figure 1B, the lateral surface of the frustoconical shape and the axis 162 parallel to the rotation axis of the impeller 100 have an average oblique angle α between them. m This can be defined. In the embodiment shown in Figure 1B, the average angle of inclination α m It is 25.5 degrees. However, in other embodiments, the average oblique angle α m This could be another angle greater than 0 degrees and less than 90 degrees. For example, in some embodiments, the average oblique angle α m This can be between approximately 2 degrees and approximately 45 degrees. In some embodiments, the average oblique angle α m This can be between approximately 5 degrees and approximately 35 degrees. In some embodiments, the average oblique angle α mThe average angle of slant α between approximately 9 and 23 degrees can be anywhere from approximately 9 to 23 degrees. m This is a larger average angle of inclination α m This can allow for a longer chord length compared to blades with a shorter chord length. A longer chord length results in a larger blade surface area, improving pressure distribution while maintaining efficiency.

[0036] For example, as shown in Figure 1B, the blade 120 has a thickness T LE It may have a thick leading edge 126.

[0037] In some embodiments, the leading edge thickness T of the blade 120 LE This can be at least about 50 mm. In some embodiments, the leading edge thickness T of the blade 120 is LE The leading edge thickness T of the blade 120 intended for use in areas where salmon smolts are present may be equal to or greater than the length of the fish species of interest in the region where the turbine, including the impeller 100, is to be installed. For example, salmon smolts 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 areas where salmon smolts are present may be greater than the leading edge thickness T of the blade 120 intended for use in areas where salmon smolts are present. LE This can be 100mm to 200mm or more.

[0038] In other embodiments, the leading edge thickness T LE The downstream impeller diameter D R The ratio to (i.e., T LE / D R ) can range from approximately 0.03 to approximately 0.2, for example, from approximately 0.08 to approximately 0.17, or from approximately 0.11 to approximately 0.14.

[0039] In some embodiments, the blade 120 may be tapered from the leading edge 126 to the trailing edge 128. The thickness of the blade 120 may be tapered such that the pressure surface 130 and the suction surface 132 intersect at a single point or a surface of very small thickness at the trailing edge 128 of the blade 120.

[0040] In some embodiments, the blade 120 may have a consistent thickness from the root 122 to the 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 tip 124 of the blade 120 than at the hub 110. The tangential velocity of the blade 120 increases from the root 122 to the tip 124. As a result, the orthogonal component of the strike velocity of the blade 120 encountering the fish 300 near the tip 124 may be greater than the orthogonal component of the strike velocity of the blade 120 encountering the fish 300 near the root 122. To reduce the risk of death in the region where the fish 300 is most likely to experience a high strike velocity, the blade may have a thick leading edge and, additionally or alternatively, a beveled leading edge, as discussed.

[0041] For example, as shown in Figure 1C, the blades 120 of the impeller 100 may have a leading edge 126 that is inclined at an angle θ at one or more locations along the leading edge 126 (e.g., locations t, m, h). (The curve can be drawn along the vertex of the blade's stationary region from the hub to the tip, defining the leading edge of the blade. A tangent drawn at any point along this curve can be measured with respect to a cylindrical surface coaxial with the rotation axis of the turbine impeller, intersecting the point. The inclination angle is measured between the tangent and a vector that lies on the cylindrical surface, is perpendicular to the leading edge, and coincides with the leading edge intersection.)

[0042] The mortality rate of fish is the normal component of the strike velocity at the time of impact. N It is a function of . Therefore, the normal component of the strike velocity at impact is w N Reducing the angle of inclination reduces fish mortality. Therefore, compared to a blunt blade at the leading edge where the inclination angle θ is not 90 degrees, mass fish mortality is reduced.

[0043] In some embodiments, the leading edge 126 at a certain location can be inclined at an angle θ of about 25 to about 50 degrees. In some embodiments, the leading edge 126 at a certain location can be inclined at an angle θ of about 30 degrees.

[0044] In some embodiments, the leading edge 126 may be inclined at the tip 124. As described above, the strike velocity increases from the base 122 of the blade 120 to the tip 124 of the blade 120, with the tip 124 of the blade 120 having the maximum strike velocity. Therefore, by providing a leading edge 126 with an inclination angle θ at the tip 124 of the blade 120, the mortality rate, at which the fish 300 are more likely to experience a fatal effect, can be reduced. Providing an inclined leading edge 126 at the tip 124 can also help prevent the construction or accumulation of debris at the tip 124, for example. An inclined leading edge 126 at the tip 124 can also help reduce the occurrence of cavitation.

[0045] In some embodiments, the leading edge 126 may be inclined at a location between the base 122 and the tip 124. For the same reasons described above with respect to providing a leading edge 126 with an inclination angle at the tip 124, providing a leading edge 126 with an inclination angle θ in the region between the base 122 and the tip 124 can reduce the mortality rate of the fish 300, which can be relatively often fatally affected.

[0046] In some embodiments, for example as shown in Figure 1C, the inclination angle θ at the tip 124 of the blade 922 can be smaller than the inclination angle θ at the root 122 and / or at the location between the root 122 and the tip 124. The inclination angle of the leading edge 126 of the blade 120 at the tip 124 can be about 20 to about 90 degrees, such as about 25 to about 45 degrees.

[0047] In some embodiments, the leading edge 126 may be inclined at the base 122. The inclination angle of the leading edge 126 of the blade 120 at the base 122 can be about 10 to 90 degrees, such as about 25 to 45 degrees. In addition to improving the survival of fish 300 that collide with the blade 120 at the base 122, providing an inclined leading edge 126 at the base 122 can help prevent the construction or accumulation of debris at the point where the base 122 of the blade 120 contacts the hub 110.

[0048] In some embodiments, for example, as shown in Figure 1C, the leading edge 126 of the blade 120 can be inclined so that the leading edge 126 is arc-shaped. In other embodiments, the leading edge 126 may have a C-shape, a semicircular shape, a parabolic shape, a conical shape, a saddle shape, or any other shape.

[0049] In some embodiments, for example as shown in Figure 1C, the leading edge 126 of the blade 120 can be curved toward the trailing edge 128 of the blade 120 near the hub 110, such that the leading edge 126 has a concave shape. This makes it possible to achieve a smaller angle at the tip 124 while minimizing cantilever or forward tilt at the tip, for example.

[0050] In some embodiments, the leading edge 126 of the blade 120 at the root 122 can be inclined at a first angle θ, and the leading edge 126 of the blade 120 at the tip 124 can be inclined at the same angle θ.

[0051] In some embodiments, the root 122 of the leading edge 126 of the blade 120 is positioned along the radial axis 160 of the impeller 100, and the tip 124 of the leading edge 126 extends beyond the radial axis 160 in the circumferential direction 170. Thus, the leading edge 126 of the blade 120 can be cantilevered circumferentially beyond the radial axis, also known as a forward bend.

[0052] The tip 124 at the leading edge 126 extends further in the circumferential direction 170 beyond the radial axis 160, allowing a smaller angle to be achieved. This allows the strike velocity w at impact to be reduced. N The normal component of the angle may decrease. However, as the angle continues to decrease, the structural stiffness of the blade may also decrease. This could increase the manufacturing cost required to maintain the minimum structural stiffness requirements for the blade. Structural stiffness may be required, for example, to keep the tip 124 of the blade 120 within the tight tolerances of the turbine housing.

[0053] In some embodiments, the impeller 100 may include a rim connecting the tips 124 of the blades 120. For example, this can reduce the occurrence of structural deflection.

[0054] 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 may both be positioned along the radial axis 160.

[0055] In some embodiments, the trailing edge 128 of the impeller 100c may have an S-shape, as shown in Figure 3C, for example. A first portion 125 of the trailing edge may be concave, and a second portion 127 of the trailing edge (e.g., a portion of the trailing edge located further from the hub than the first portion) may be convex. In some embodiments, a first portion of the pressure surface 130 adjacent to the first portion of the trailing edge 128 is concave, and a second portion of the pressure surface 130 adjacent to the second portion of the trailing edge 128 (also located further from the hub than the first portion of the pressure surface 130) is convex. In some embodiments, a suction surface 132 adjacent to the trailing edge 128 is convex along most of the trailing edge 128. In some embodiments, the impeller 100 is configured to rotate such that the orthogonal component of the strike velocity is about 7 m / s or less in order to allow the safe passage of fish (e.g., the safe passage of salmon). In some embodiments, the impeller 100 is configured to rotate such that the orthogonal component of the strike velocity is about 10 m / s or less to allow fish (safe passage of eels). By providing an inclined leading edge 126, the orthogonal component of the strike velocity is effectively reduced, allowing the impeller 100 to rotate at a higher speed to improve the power ratio speed and economic competitiveness of the impeller 100 while maintaining safe passage of fish.

[0056] In some embodiments, for example as shown in Figure 1C, the blades 120 can be shaped such that they do not overlap each other when viewed along the shaft axis 150 of the impeller 100.

[0057] 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 / fiberglass and resin. In such embodiments, the blade 120 may include a core made of lightweight foam. In some embodiments, the impeller 100 can be made of a metal such as bronze or stainless steel and formed by casting which is machined into a final shape. In some embodiments, the impeller 100 and / or blade 120 are hollow. In some embodiments, the impeller 100 is made of a composite material and is manufactured via conventional methods of composite construction. For example, the impeller 100 may have a sandwich composite structure, or it may include a shear web inside the structure, or it may be made as a monocoque structure with thick walls. In some embodiments, the impeller 100 is made of an elastomer or polymer and has reinforcing materials dispersed locally or throughout its interior.

[0058] The blade 120 may have a hybrid structure. In some embodiments, the leading edge 126 of the blade 120 is armored. The leading edge 126 may include a coating. The leading edge 126 may be metal. In some embodiments, the blade tip 124 is molded with a thick layer of ablative material so that the blade tip 124 can wear into the inner diameter of the turbine housing 104 (for example, as shown in Figure 1B).

[0059] In some embodiments, the diameter D of the impeller 100 R The diameter D of the impeller 100 can be at least about 0.4 meters. In some embodiments, the diameter D of the impeller 100 R This could range from approximately 0.4 meters to approximately 7 meters, for example, from approximately 1 meter to approximately 5 meters.

[0060] Axial length L of impeller 100 R Diameter D of the impeller 100 downstream of the impeller 100R The ratio to can vary depending on the angle of slant. For example, an impeller with a relatively small average angle of slant (e.g., about 1.5 degrees) will have a relatively large ratio of L. R / D R (For example, it can have a ratio L of approximately 0.4 to approximately 0.6). As another example, an impeller with a relatively large average angle of inclination (for example, approximately 25 degrees) can have a relatively small ratio L R / D R (For example, it may have values ​​ranging from approximately 0.25 to approximately 0.4.)

[0061] In some embodiments, the impeller 100 is integrated with the turbine 200 (for example, as shown in Figure 1B). In Figure 1B, the shaft axis 150 is perpendicular to the ground. However, in other embodiments, the shaft axis 150 can be horizontal to the ground, or at an angle between horizontal and perpendicular to the ground.

[0062] In some embodiments, the turbine may include commonly known inlet and outlet elements. The inlet element may include, for example, a helical or semi-helical shape. In some embodiments, the inlet of the turbine 200 is intended to be connected to a pressure pipe, a penstock, or the discharge of the scroll case. The outlet element may include, for example, a draft tube. The draft tube may have a change in cross-sectional area suitable for recovering the velocity head. The draft tube may be straight or curved, as is appropriate given characteristics of the hydroelectric plant.

[0063] During operation, water flows into the turbine, passes through the stages of guide vanes (which may be fixed in a pitch as needed depending on the application, or adjustable as needed) if guide vanes are present, passes through the impeller 100, and is discharged into a diffuser or draft tube, from which it can enter a discharge channel or an outlet pipe that sends the discharged water to the discharge channel.

[0064] In some embodiments, the turbine operates at a head of at least 1 meter. In some embodiments, the turbine operates at a head of at least 10 meters. In some embodiments, the turbine operates at a head of at least 20 meters. In some embodiments, the turbine operates at a head of at least 30 meters. In some embodiments, the turbine operates at a head of at least 40 meters.

[0065] In some embodiments, the impeller 100 can be integrated into the turbine, and the turbine can be part of a hydroelectric power plant that includes several turbines.

[0066] In some embodiments, the impeller 100 is retrofitted to an existing turbine or hydroelectric power plant. The impeller 100 may be used to repair, upgrade, or modernize an existing turbine or hydroelectric power plant. In retrofitting, it is often important to minimize changes to existing civil engineering and electrical infrastructure. For example, retrofitting may have strict constraints, such as utilizing an existing generator at a fixed shaft speed, positioning the impeller at a predetermined height relative to tailwater rise, or operating within an existing intake chamber, discharge ring, or draft tube, all of which severely limit the design envelope through which a fish-safe impeller can be formed.

[0067] Figures 2A to 2C show impeller 100b according to another embodiment. Figure 2A shows a perspective view of impeller 100b, Figure 2B shows a side view of impeller 100b, and Figure 2C shows an upstream view of impeller 100b.

[0068] Impeller 100b may include some or all of the features, structures, or characteristics described above with respect to impeller 100. For example, impeller 100b may include a hub 110b, blades 120b, root 122b, tip 124b, leading edge 126b, trailing edge 128b, pressure surface 130b, and suction surface 132b, which may include some or all of the features, structures, or characteristics described above with respect to hub 110, blades 120, root 122, tip 124, leading edge 126, trailing edge 128, pressure surface 130, and suction surface 132.

[0069] In the embodiments shown in Figures 2A to 2C, the impeller 100b has a tapered hub 110b. The impeller 100b has a blade tip 124b that defines a roughly cylindrical outer shape. The surface swept from the circle intersecting at the midpoint of the leading edge of the blade 120b to the circle intersecting at the midpoint of the trailing edge of the blade 120b has a frustoconical shape. Referring to Figure 2C, the impeller 100b has an average oblique angle α of about 2 degrees. m It has.

[0070] The impeller 100b may be suitable, for example, in conditions involving a cylindrical turbine housing and in operation in a hydroelectric power plant with a head between 2m and 10m.

[0071] Figures 3A to 3C show impeller 100c according to another embodiment. Figure 3A shows a perspective view of impeller 100c, Figure 3B shows a side view of impeller 100c, and Figure 3C shows an upstream view of impeller 100c.

[0072] Impeller 100c may include some or all of the features, structure, or characteristics described above for impeller 100. For example, impeller 100c may include a hub 110c, a blade 120c, a root 122c, a tip 124c, a leading edge 126c, a trailing edge 128c, a pressure surface 130c, and a suction surface 132c, which may include some or all of the features, structure, or characteristics described above for hub 110, blade 120, root 122, tip 124, leading edge 126, trailing edge 128, pressure surface 130, and suction surface 132.

[0073] In the embodiments shown in Figures 3A to 3C, the impeller 100c has a tapered hub 110c. The impeller 100c has a blade tip 124 that defines an outer frustoconical shape that tapers from the inlet side to the outlet side of the impeller 100. The surface swept from the circle intersecting the midpoint of the leading edge of the blade 120c to the circle intersecting the midpoint of the trailing edge of the blade 120c has a frustoconical shape. Referring to Figure 3C, the impeller 100c has an average oblique angle α of approximately 6 degrees. m It has.

[0074] For example, the impeller 100c includes a turbine housing having a frustoconical shape and may be suitable for operating conditions in a hydroelectric power plant with a head between 10m and 30m.

[0075] Figures 4A to 4C show impeller 100d according to another embodiment. Figure 4A shows a perspective view of impeller 100d, Figure 4B shows a side view of impeller 100d, and Figure 4C shows an upstream view of impeller 100d.

[0076] Impeller 100d may include some or all of the features, structures, or characteristics described above for impeller 100. For example, impeller 100d may include a hub 110d (also known as a crown), blades 120d, root 122d, tip 124d, leading edge 126d, trailing edge 128d, pressure surface 130d, and suction surface 132d, which may include some or all of the features, structures, or characteristics described above for hub 110, blades 120, root 122, tip 124, leading edge 126, trailing edge 128, pressure surface 130, and suction surface 132.

[0077] In the embodiments shown in Figures 4A to 4C, the impeller 100d is a Francis type impeller. The impeller 100d may have a tapered hub 110d (also known as a crown) joined by a rim 134d and a blade tip 124d. The blade tip 124d terminates on a plane of rotation having an increasing cross-section when measured along the shaft axis 150d. The surface swept from the circle intersecting the midpoint of the leading edge of blade 120d to the circle intersecting the midpoint of the trailing edge of blade 120d has a frustoconical shape. Referring to Figure 4B, the average angle of slant α of the impeller 100d m It is approximately 17 degrees.

[0078] In the embodiments shown in Figures 4A to 4C, the impeller 100d has an impeller diameter D downstream of the impeller 100d. R It has. The impeller 100d can be designed over a wide range of sizes. Impeller diameter D R The impeller diameter may be in the range of approximately 0.5 meters to approximately 7 meters, or in the range of 1 meter to approximately 6 meters. If the turbine has fixed-pitch blades, the impeller diameter may be smaller. In some examples, the impeller diameter D R This can be approximately 3.6 meters. In some embodiments, the average radius of the leading edge (i.e., the radius of the circle intersecting the midpoint of the leading edge of blade 120d) is approximately 2 meters, the average radius of the trailing edge (i.e., the radius of the circle intersecting the midpoint of the trailing edge of blade 120d) is approximately 1.6 meters, the axial displacement between these two average circles is approximately 0.8 meters, and the average oblique angle α of impeller 100d is approximately 3.6 meters. m The angle is approximately 17 degrees. The leading edge thickness of the blade 120d of the impeller 100d near the tip 124d of blade 120d is approximately 0.28m, or 0.07D. R (That is, impeller diameter D) R (This is obtained by multiplying by 0.07). The leading edge thickness of blade 120d near the root 122d of blade 120d is approximately 0.15m, or 0.04D. R The leading edge 126d at the tip 124d has an inclination angle θ of approximately 45 degrees.

[0079] For example, impeller 100d may be suitable for applications typically considered for Francis turbines and for operating conditions in hydroelectric power plants with heads between 8m and 40m.

[0080] Figures 5A and 5B show impellers 100e according to several embodiments. Figure 5A shows a perspective view of impeller 100e, and Figure 5B shows an upstream view of impeller 100e. Impeller 100e may include some or all of the features, structures, or characteristics described above for impeller 100, as shown in Figures 1A and 1C. For example, impeller 100e may include a hub 110e, blades 120e, root 122e, tip 124e, leading edge 126e, trailing edge 128e, pressure surface 130e, and suction surface 132e, which may include some or all of the features, structures, or characteristics described above for hub 110, blades 120, root 122, tip 124, leading edge 126, trailing edge 128, pressure surface 130, and suction surface 132.

[0081] The impeller 100e in Figure 5A differs from the impeller 100 in Figures 1A-C in several respects, as described above. The impeller 100e may have a different number of blades. While the impeller 100 has four blades, the impeller 100e has several blades, as best shown in Figure 5B. The impeller 100e may have a different number of blades, such as 5 to 10 blades. Fish safety can be improved by an impeller with fewer blades than a conventional turbine impeller. Fewer blades help reduce the probability of fish striking, as a higher probability of fish striking correlates to higher fish injury and death. Furthermore, fish safety is improved by forming an impeller with a large leading edge thickness, as described herein. Thicker blades occupy more space within the turbine, so reducing the number of blades helps increase the available space for water flow through the turbine, thus improving performance.

[0082] In the embodiments shown in Figures 5A and 5B, the impeller 100e may have a tapered hub 110e. The hub 110e may be tapered from the upstream end to the downstream end of the impeller 100e. The impeller 100e may have blade tips 124e that define a generally cylindrical outer shape. The surface swept from the circle intersecting the midpoint of the leading edge of the blade 120e to the circle intersecting the midpoint of the trailing edge of the blade 120e may have a frustoconical shape. For example, the impeller 100e may include a cylindrical turbine housing and be suitable for operating conditions in a hydroelectric power plant with a head between 2m and 10m.

[0083] In the impeller 100e shown in Figures 5A and 5B, the average angle of sleight is shallower than that of the impeller 100 shown in Figures 1A and 1C. A shallower average angle of sleight allows for a larger blade surface area for impellers with the same hub diameter-to-tip diameter ratio. The shallower angle and larger surface area help improve the pressure distribution through the impeller, minimizing or reducing the risk of cavitation, thereby improving the safety of fish passing through the impeller. In some embodiments, the average angle of sleight is in the range of approximately 9 to approximately 23 degrees.

[0084] The shape of the impeller 100e can determine the angle of the fluid flowing through the turbine. For example, the leading edge 126e of the impeller 100e may have a concave shape and be thicker than the trailing edge 128e, and the tip 124 of the leading edge 126e may be twisted, which results in a diagonal flow of the fluid flowing through the turbine system, as shown in Figures 5A and 5B. In some examples, the surface of the tip 124e may be positioned further downstream toward the leading edge, and as the tip 124e extends toward the trailing edge 128e, the surface of the tip 124e may be twisted so that the surface faces further upstream toward the trailing edge 128e. In some examples, a portion of the trailing edge 128e may be bowed downstream toward the tip 124e of the trailing edge 128e. The middle portion of the trailing edge 128e may be further downstream than the tip 124e or root 122e of the trailing edge 128e.

[0085] Figures 6A and 6B show impellers 100f according to several embodiments. Figure 6A shows a perspective view of impeller 100f, and Figure 6B shows an upstream view of impeller 100f. Impeller 100f may include some or all of the features, structures, or characteristics described above with respect to impeller 100. In particular, impeller 100f may have similar features to those described with respect to Figures 2A to 3C. For example, impeller 100f may include a hub 110f, blades 120f, root 122f, tip 124f, leading edge 126f, trailing edge 128f, pressure surface 130f, and suction surface 132f, which may include some or all of the features, structures, or characteristics described above with respect to the hub 110, blades 120, root 122, tip 124, leading edge 126, trailing edge 128, pressure surface 130, and suction surface 132.

[0086] In the embodiments shown in Figures 6A and 6B, the impeller 100f may have a tapered hub 110f. The impeller 100f may have a blade tip 124f that defines a generally cylindrical outer shape. The surface swept from the circle intersecting the midpoint of the leading edge of the blade 120f to the circle intersecting the midpoint of the trailing edge of the blade 120f may have a frustoconical shape. For example, the impeller 100f may include a cylindrical turbine housing and be suitable for operating conditions in a hydroelectric power plant with a head between 2m and 10m.

[0087] Similar to impeller 100e, the shape of impeller 100f can define the angle of the fluid flowing through the turbine. The leading edge 126f of impeller 100f may be concave, and the leading edge 126f may be thicker than the trailing edge 128f. The tip 124 of the leading edge 126f may be twisted. Figures 5A and 5B show impeller 100e having seven blades 120e, and Figures 6A and 6B show impeller 100f having four blades 120f. Impellers with fewer blades may have more space between the trailing edge and the leading edge of the adjacent blade. For example, Figure 6B shows impeller 100f having four blades 120f, where space is formed between the leading edge 126f of blade 120f and the trailing edge of the adjacent blade.

[0088] The impeller blade 120f shown in Figure 6 may have a smaller ratio of tip chord to root chord than the blades 120b and 120c in Figures 2 and 3. In other words, the root chord is proportionally longer to blade 120f than to blades 120b and 120c. Furthermore, the trailing edge 128f of the root 122f extending downstream may result in a chord that is proportionally longer to blade 120f compared to blades 120b and 120c. The ratio of tip chord to root chord in Figure 6 may be in the range of 1.3 to 1.7, while the ratio of tip chord to root chord in the impellers shown in Figures 2 and 3 may be in the range of 1.9 to 2.5. Increasing the root chord length improves the pressure distribution along blade 120f and increases efficiency. For example, as shown in Figure 6B, the blade 120f of the impeller 100f may have a leading edge 126f that is inclined at an angle θ at one or more locations (e.g., locations t, m, h) along the leading edge 126f. The curve may be drawn along the vertex of the blade's stationary region from the hub to the tip, defining the leading edge of the blade. A tangent drawn at any point along this curve can be measured with respect to a cylindrical surface coaxial with the rotation axis of the turbine impeller, intersecting the point. The inclination angle is measured between the tangent and a vector that lies on the cylindrical surface, is perpendicular to the leading edge, and coincides with the leading edge intersection.

[0089] In the embodiments shown in Figures 7A to 7B, the impeller 100g is a Francis type impeller. The impeller 100g may have the same features as described above with reference to the impellers in Figures 4A to 4B. The impeller 100g may have a tapered hub 110g (also known as a crown). The impeller 100g may have a blade tip 124g joined by a rim 134g. However, in some embodiments, the impeller 100g does not include a rim 134g. The blade tip 124g terminates on a rotating surface having an increasing cross-section when measured along the shaft axis 150g. The surface swept from the circle intersecting the midpoint of the leading edge of the blade 120g to the circle intersecting the midpoint of the trailing edge of the blade 120g has a frustoconical shape.

[0090] In the embodiments shown in Figures 7A to 7C, the impeller 100g has an impeller diameter D of approximately 4 to 6 meters. R It has a diameter of, for example, 3.6 meters. In some embodiments, the leading edge 126g can be about 250mm to 280mm thick. For example, in the case of an impeller with a diameter of 3.6 meters, the leading edge thickness t is about 0.07 to 0.08. LE Impeller diameter D R Ratio to (t) LE / D R ) may have.

[0091] In some embodiments described herein, the impeller may have blades having a trailing edge that extends from the root to the tip of the blade, the trailing edge at the tip being positioned upstream of the trailing edge at the root.

[0092] Figure 8A shows a side view of impeller 100e having a trailing edge at the downstream tip of the trailing edge at the root. Impeller 100e has a blade having point A1 at the tip 124e of the leading edge 126e, point B1 at the tip 124e of the trailing edge 128e, and point C1 at the root 122e of the leading edge 126e. Figure 8B is a cross-sectional view of blade 120e taken along line EE in Figure 8A. As shown in Figure 8B, impeller 100e may have points A1, B1, and C1, and may have point D1 located at the trailing edge 128e of the root 122e. Figure 8B shows the origin 200e corresponding to the axis of rotation of impeller 100e. Axis 202e extends from the origin 200e through A1, axis 204e extends through B1, axis 206e extends through C1, and axis 208e extends through D1. Angle θ a1 This can be defined between axes 204e and 208e. Figure 8B also shows the angle θ i1 The angle θ may be defined between axis 202e and axis 206e. i1 angle θ a1 This shows that it can become even larger. Angle θ i1 The angle can be between approximately 20 and 50 degrees. i1 This relates to the range of cantilever or forward tilt of the blade 120e. In some examples, the angle θ within this range is relevant. i1This allows the blade 120e to have a stagger angle (i.e., the angle between the blade chord line and the axial flow direction, where a stagger angle of 0 degrees is parallel to the flow) in the range from the root 122e to the tip 124e. i1は The angle may be between approximately 8 and 20 degrees, thereby enabling a suitable range of root chord and root stagger in combination with the tip stagger and leading edge 126e forward bevel.

[0093] Figure 8C is an axial cross-sectional view of the blade 120e of impeller 1003 showing the region or cross-section swept by the impeller, which may also be referred to herein as a “meridian” cross-sectional view. An axial cross-section can refer to the region swept by the blade when viewed along an axis perpendicular to the shaft axis (i.e., when the impeller is viewed from the side). Impeller 100e has a blade 120e having a midline m1 defined as an intermediate portion between the root 122e and the tip 124e. For example, the midline m1 may intersect the midpoint between points A1 and C1 on the leading edge 126e and the midpoint between points B1 and D1 along the trailing edge 128e. In some examples, point C1 may be located upstream of point A1, and both points A1 and C1 may be located upstream of points B1 and D1. Point D1 is located downstream of point B1. As a result, the chord length C1-D1 is longer than that of a blade with D1 upstream of B1. This helps increase the blade length and surface area, improving the pressure distribution through the impeller and thus improving fish safety.

[0094] Points A1 and B1 can be positioned at approximately the same distance from the shaft axis 150e, and both points A1 and B1 can be positioned further from the shaft axis 150e than points C1 and D1. Point C1 can be positioned even further from the shaft axis 150e than point D1. In the example of Figure 8C, the leading edge 126e may be concave. D1 can be positioned at a distance d1 from the shaft axis 150e, and B1 can be positioned at a distance b1 from the shaft axis 150e. The ratio of d1 to b1 (i.e., d1 / b1) can be between 0.15 and 0.35.

[0095] As shown in Figure 8C, the distance between point A and point B may be smaller than the distance between point C and point D. In other words, the length of blade 120e at tip 124e (i.e., the surface between points A and B) may be smaller than the length of blade 120e at root 122e (i.e., the surface between points C and D).

[0096] Average diagonal angle α m1 α can be defined as the angle between the midline m1 and the line 210e parallel to the shaft axis 150e, where line 210e intersects the midline at its leading edge 126e. m1 This can be between approximately 2 and 15 degrees. In some cases, the average angle of inclination α m1 It can be between approximately 2 and 10 degrees.

[0097] Figure 9A shows a side view of the impeller 100f. The impeller 100f may include an outer rim that connects the tip 124f of the blade 120f around the circumference of the impeller 100f. The average angle of inclination α of the impeller 100f. m2 This can be defined as the distance between the midline m2 and the line 210f parallel to the shaft axis 150f, where line 210f intersects the midline at its leading edge 126f. The average oblique angle α of the impeller 100f. m2 The average angle of inclination is α m1 It can be larger, but is defined below and is shown in Figure 10C as the average angle of inclination α m3 It can become smaller. Average angle of inclination α m2 The angle α can be between approximately 9 and 23 degrees. m3 This can allow the blades to have longer chord lengths, increasing the blade surface area. This can help improve pressure distribution and maintain turbine efficiency.

[0098] Impeller 100f may have more blades than impeller 100g, and the blades of impeller 100f may have a larger average angle of inclination. Impeller 100f has point A2 at the tip 124f of the leading edge 126f, point B2 at the tip 124f of the trailing edge 128f, and point C2 located at the root 122f of the leading edge 126f. Figure 9B is a cross-sectional view of blade 120f taken along line FF in Figure 9A. As shown in Figure 9B, impeller 100f may have points A2, B2, and C2, and point D2 located at the trailing edge 128f of the root 122f. The origin 200f corresponds to the shaft axis, around which impeller 100f rotates. Axis 202f extends from the origin through A2, axis 204f extends through A2, axis 206f extends through C2, and axis 208f extends through D2. Angle θ a2 This can be defined between axis 204f and axis 208f. Angle θ a2 The angle can be between approximately 8 and 20 degrees. i2 This can be defined between axis 202f and axis 206f, θ i2 is, angle θ a2 It can become larger. Angle θ a2 It can be between approximately 25 and 35 degrees.

[0099] Figure 9C is an axial cross-sectional view of blade 120f, sometimes called a meridian cross-sectional view. Figure 9C shows a midline m2 defined as the intermediate portion between the root 122f and the tip 124f. For example, the midline m2 may intersect the midpoint between points A2 and C2 on the leading edge 126f, and the midpoint between points B2 and D2 on the trailing edge 128f. In some examples, point A2 may be located upstream of point C2, or points A2 and C2 may be located substantially coplanar along the shaft axis 150f. Points A2 and C2 may be located upstream of points B2 and D2. Point B2 may be located upstream of point D2. In this way, the chord length and surface area of ​​the blade are increased compared to a blade with D2 upstream of B2 without increasing the diameter of the impeller.

[0100] Point A2 may be further from the shaft axis 150f than point B2, and both points A2 and B2 may be positioned further from the shaft axis 150f than points C2 and D2. Point C2 may be positioned further from the shaft axis 150f than point D2. In the example of Figure 9C, the surface shape of the leading edge 126f may be concave, and the surface shape of the trailing edge 128f may be convex. D2 may be positioned at a distance d2 from the shaft axis 150f, and B2 may be positioned at a distance b2 from the shaft axis 150f. The ratio of d2 to b2 (i.e., d2 / b2) may be between approximately 0.25 and 0.5.

[0101] Figure 10A shows a side view of impeller 100g, which is a Francis type impeller. Impeller 100g may have multiple blades 122g. Each blade 120g may have a leading edge 126g with a first portion 128g adjacent to the root of the blade and a second portion 129g adjacent to the tip of the blade 120g. As shown in Figure 10A, the second portion 129g is inclined or curved forward of the vertical axis Z. In contrast, impeller 100d in Figures 4A-4C has a leading edge 126d at the root 122d that is substantially collinear with the shaft axis 150d of impeller 100d. Blade 120 in Figure 4B has an angle θ of blade 120g shown in Figure 10B. i3 An angle smaller than θ i It may have an angle θ. i The angle can be between approximately 23 and 35 degrees, and the angle θ i3 This can be between approximately 50 and 60 degrees. Angles outside this range make blade manufacturing significantly more difficult and may only achieve fish safety in a gradual manner. Blade 120g in Figure 10B also has a greater forward bevel, i.e., a larger cantilevered leading edge 126d, compared to blade 120d in Figure 4B. Blades with a greater forward bevel generally achieve better fish strike survival along the leading edge and result in a more efficient pressure distribution along the blade compared to blades with a smaller forward bevel.

[0102] The impeller 100g has a point A3 at a tip 124g of a leading edge 126g, a point B3 at a tip 124g of a trailing edge 128g, and a point C3 at a root 122g of the leading edge 126g. Fig. 10B is a cross-sectional view of the blade 120g taken along line G-G in Fig. 10A. As shown in Fig. 10B, the impeller 100g may have point A3, point B3, and point C3, and may have a point D3 disposed at the root 122g of the trailing edge 128g. The origin 200g may correspond to the shaft axis of the impeller 100g. The axis may be defined by intersections between the origin and a line 202g extending through A3, an axis 204g extending from the origin through B3, an axis 206g extending from the origin through C3, and an axis 208g extending from the origin through D3. In some examples, the axis 206g may extend through D3, the axis 208g may extend through C3, and the axes 206g and 208g are configured to be collinear. In some examples, the axis 206g may deviate slightly from the axis 208g. The angle θ a3 may be defined between the axis 204g and the axis 208g. The angle θ a3は may be between about 15 degrees and about 25 degrees. The angle θ i3 may be defined between the axis 202g and the axis 206g, and the angle θ i3 may be larger than the angle θ a3 . The angle θ i3 may be between about 30 degrees and about 60 degrees. An angle θ i3 outside this range makes blade manufacturing significantly difficult and may only achieve incremental improvements in fish safety. Blades within this range also provide a more efficient pressure distribution along the blade compared to blades outside this range, resulting in improved efficiency in turbine operation.

[0103] Figure 10C is an axial cross-sectional view of the blade 120g of Figure 10A, which may also be called a meridian cross-sectional view. The blade 120g has a midline m3 defined as an intermediate portion between the root 122g and the tip 124g. For example, the midline m3 can intersect the midpoint between points A3 and C3 on the leading edge 126g and the midpoint between points B3 and D3 along the trailing edge 128g. In some examples, point A3 may be located downstream of points C3 and D3, and point D3 may be located downstream of point C3. Point B3 may be located downstream of point A3. Points D3 and C3 may be located upstream of the midline m3 on the leading edge 126g, and points A3 and B3 may be located downstream of the midline m3 on the leading edge 126g.

[0104] Point A3 may be further from the shaft axis 150g than point B3, and both points A3 and B3 may be located further from the shaft axis 150g than points C3 and D3. Point C3 may be located further from the shaft axis 150g than point D3. In the example of Figure 10C, the surface of the leading edge 126g may be concave. In some embodiments, the distance from the shaft axis 150g may decrease and then increase as the surface of the leading edge 126g extends from the midline m3 to point C3. In other words, the surface of the leading edge 126g may extend away from the midline m3 and then curve back toward the midline m3. The surface shape of the trailing edge 128g may be convex. D3 may be located at a distance d3 from the shaft axis 150g, and B3 may be located at a distance b3 from the shaft axis 150g.

[0105] Average diagonal angle α m3 α can be defined as the angle between the midline m3 and a line 210g parallel to the shaft axis 150g, where line 210g intersects the midline at the leading edge 126g. The average angle of slant can be between approximately 25 and 40 degrees. In some examples, the average angle of slant α m3 The average angle of inclination α can be between approximately 25 and 35 degrees. m3 The average angle of inclination is α m2 and α m1 It can become even larger.

[0106] Any of the impellers described herein may include a rim. The rim may be configured as a ring coupled to the tip of each blade. The rim contacts the inner wall of the turbine housing during the operation of the impeller. The rim helps to improve the rigidity of the impeller and blades and also helps to prevent fluid leakage around the blades.

[0107] It should be understood that the interpretation of the claims is intended to be based on the section describing embodiments for carrying out the invention, rather than the section describing the summary and abstract of the invention. The section describing the summary and abstract of the invention may describe, but not all, one or more exemplary embodiments of the invention(s) contemplated by the inventor, and is therefore not intended in any way to limit the invention(s) and the appended claims.

[0108] The present invention(s) have been described above with functional components that exemplify the implementation of specific functions and their relationships. The boundaries of these functional components are defined herein as appropriate for explanatory purposes. Other boundaries may also be defined, as long as the specific functions and their relationships are adequately implemented.

[0109] The foregoing descriptions relating to specific embodiments are intended to fully illustrate the general nature of the invention(s) and will allow those skilled in the art to readily modify and / or adapt such specific embodiments to various uses without excessive experimentation and without departing from the general outline of the invention(s) by applying knowledge within the scope of the art. Such adaptations and modifications are therefore intended to be within the meaning and scope of equivalent embodiments disclosed herein, based on the teachings and guidance provided herein. It should be understood that the expressions and terms herein are for illustrative purposes only and not for limitation. Therefore, the terms and expressions herein should be interpreted by those skilled in the art in light of the teachings and guidance.

[0110] The scope and extent of the present invention should not be limited by any of the exemplary embodiments described above, but should be defined solely in accordance with the following claims and their equivalents.

[0111] Further exemplary embodiments of the present invention are described in the following sections.

[0112] In some embodiments, the impeller may have a hub and a plurality of blades extending from the hub, the number of blades ranging from 5 to 8, and can be as many as 7.

[0113] In some embodiments, the impeller blades include a midline extending from the midpoint of the leading edge of the blade to the midpoint of the trailing edge of the blade, and the angle between the midline and an axis parallel to the shaft axis of the blade is shallow, ranging from about 2 to about 45 degrees, and may be in the range of about 2 to about 10 degrees.

[0114] In some embodiments, the impeller blades include a trailing edge extending from the root to the tip of the blade, with the trailing edge at the root positioned downstream of the tip of the trailing edge.

[0115] In some embodiments, the chord length from the tip of the blade at the leading edge to the tip of the blade at the trailing edge is greater than the chord length from the root of the leading edge to the root of the trailing edge.

[0116] In some embodiments, the impeller may include a rim that includes rings coupled to the tip of each of the multiple blades of the impeller.

[0117] In some embodiments, the impeller includes a Francis turbine impeller, which includes a hub and a plurality of blades connected to the hub, the blades of the plurality of blades having a leading edge having a first portion and a second portion, the first portion being inclined or curved rearward along an axis parallel to the shaft axis of the impeller, and the second portion being inclined or curved forward along an axis parallel to the shaft axis. The first portion is located near the root of the blade, and the second portion is located near the tip of the blade.

Claims

1. Hub and, Multiple blades extending from the hub, Includes, Each of the plurality of blades includes a root located in the hub, a tip opposite the root, a leading edge, and a trailing edge opposite the leading edge, The impeller is configured to rotate around a rotation axis, Each of the plurality of blades has a leading edge midpoint along the leading edge of the blade and a trailing edge midpoint along the trailing edge of the blade in the meridian section of the blade, Average diagonal angle α ｍ It is defined between the axis of rotation and the midline that intersects the midpoint of the leading edge and the midpoint of the trailing edge, At least one of the plurality of blades has a ratio T greater than approximately 0.03 of the thickness of the leading edge to the diameter of the impeller downstream of the impeller. ＬＥ / D Ｒ Includes, A hydraulic turbine impeller, wherein, with respect to at least one blade, the leading edge at the root is positioned along the radial axis of the impeller, and the leading edge at the tip is cantilevered in the circumferential direction of the impeller, extending beyond the radial axis.

2. The impeller according to claim 1, wherein the maximum leading edge thickness of at least one of the blades is at least about 50 mm.

3. The impeller according to claim 1, wherein the maximum leading edge thickness of at least one blade is at least about 100 mm.

4. The impeller according to claim 1, wherein the maximum leading edge thickness of at least one of the blades is at least about 200 mm.

5. The average oblique angle α ｍ The impeller according to claim 1, wherein the angle is greater than 0 degrees and less than 90 degrees.

6. The average oblique angle α ｍ The impeller according to claim 1, wherein the angle is between approximately 2 degrees and approximately 45 degrees.

7. The average oblique angle α ｍ The impeller according to claim 1, wherein the angle is between approximately 9 degrees and approximately 23 degrees.

8. The impeller according to claim 1, further comprising an outer rim connecting the blade tip around the circumference of the impeller.

9. The impeller according to claim 1, wherein the leading edge thickness of at least one of the blades at the tip of the blade is greater than the leading edge thickness at the base of the blade.

10. The impeller according to claim 1, wherein the plurality of blades include three or more blades.

11. The impeller according to claim 1, wherein the plurality of blades include 5 to 10 blades.

12. The impeller according to claim 1, wherein the leading edge of at least one of the blades is saddle-shaped.

13. The impeller according to claim 1, wherein a portion of the leading edge at the tip of at least one of the blades is inclined forward in the direction of rotation of the blade.

14. The impeller according to claim 1, wherein the portion of the leading edge at the tip of the blade is inclined at an angle in the range of about 20 degrees to about 90 degrees.

15. The impeller according to claim 1, wherein the portion of the leading edge at the tip of the blade is inclined at an angle in the range of about 25 degrees to about 45 degrees.

16. The impeller according to claim 1, wherein the trailing edge at the base is positioned downstream of the trailing edge at the tip.

17. The impeller according to claim 1, wherein the diameter of the impeller is between approximately 0.5 meters and 7 meters.

18. A housing that defines the inlet and outlet for the flow of water, The impeller according to claim 1, positioned within the housing, A turbine that includes a turbine.

Images