WO2022171336A1 - Runner for a hydraulic turbine or pump - Google Patents

Runner for a hydraulic turbine or pump Download PDF

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Publication number
WO2022171336A1
WO2022171336A1 PCT/EP2021/085817 EP2021085817W WO2022171336A1 WO 2022171336 A1 WO2022171336 A1 WO 2022171336A1 EP 2021085817 W EP2021085817 W EP 2021085817W WO 2022171336 A1 WO2022171336 A1 WO 2022171336A1
Authority
WO
WIPO (PCT)
Prior art keywords
runner
trailing edge
protrusion
blade
hydraulic turbine
Prior art date
Application number
PCT/EP2021/085817
Other languages
French (fr)
Inventor
Stuart Coulson
Steven MC HALE
Jesse ZOLL
Richard Reese
Jason FOUST
Brandon HARMER
Original Assignee
Voith Patent Gmbh
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Voith Patent Gmbh filed Critical Voith Patent Gmbh
Publication of WO2022171336A1 publication Critical patent/WO2022171336A1/en

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Classifications

    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F03MACHINES OR ENGINES FOR LIQUIDS; WIND, SPRING, OR WEIGHT MOTORS; PRODUCING MECHANICAL POWER OR A REACTIVE PROPULSIVE THRUST, NOT OTHERWISE PROVIDED FOR
    • F03BMACHINES OR ENGINES FOR LIQUIDS
    • F03B11/00Parts or details not provided for in, or of interest apart from, the preceding groups, e.g. wear-protection couplings, between turbine and generator
    • F03B11/002Injecting air or other fluid
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F03MACHINES OR ENGINES FOR LIQUIDS; WIND, SPRING, OR WEIGHT MOTORS; PRODUCING MECHANICAL POWER OR A REACTIVE PROPULSIVE THRUST, NOT OTHERWISE PROVIDED FOR
    • F03BMACHINES OR ENGINES FOR LIQUIDS
    • F03B3/00Machines or engines of reaction type; Parts or details peculiar thereto
    • F03B3/12Blades; Blade-carrying rotors
    • F03B3/121Blades, their form or construction
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F05INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
    • F05BINDEXING SCHEME RELATING TO WIND, SPRING, WEIGHT, INERTIA OR LIKE MOTORS, TO MACHINES OR ENGINES FOR LIQUIDS COVERED BY SUBCLASSES F03B, F03D AND F03G
    • F05B2240/00Components
    • F05B2240/20Rotors
    • F05B2240/30Characteristics of rotor blades, i.e. of any element transforming dynamic fluid energy to or from rotational energy and being attached to a rotor
    • F05B2240/304Details of the trailing edge
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02EREDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00Energy generation through renewable energy sources
    • Y02E10/20Hydro energy

Definitions

  • the present invention relates generally to hydroelectric turbine or pump installations. More particularly, this invention pertains to hydroelectric installations with means for enhancing the level of dissolved gas in water passing through the turbine or pump.
  • U.S. Pat. No. 5,924,842 to Beyer, James R. discloses a runner for a Francis turbine comprising a crown; a band substantially concentric with the crown; and a plurality of blades extending between crown and the band at spaced intervals along the crown, each blade fixedly secured to the crown at an inner edge and to the band at a distal outer edge, each blade having a water directing surface defined by a pressure side, an opposite facing suction side, a leading edge and a spaced apart trailing edge, at least one of the blades including: a leading edge blade portion having a rear edge in which a first slot is machined along at least a portion of the rear edge; a trailing portion having a front edge in which a second slot is machined along at least a portion of the front edge; wherein the trailing portion is fixedly secured
  • the objective of the mentioned state of the art is to increase the level of dissolved oxygen downstream of the turbine or pump by introducing an oxygen containing gas into the water passing through the unit.
  • the amount of gas introduced into the water passing through the unit depends on the pressure conditions on the low-pressure side of the runner. For example when the tailwater level rises and therefore the backpressure is increased, the aeration capability of the prior art designs may become ineffective.
  • the downstream level (often referred to as tail water level) rises as more flow is passed through the turbine(s) of the hydro plant or if flow is released over an adjacent spillway.
  • the resulting higher tail water level increases the pressure at the outlet of the turbine.
  • the source of the oxygen containing gas is often atmospheric air in the hydro plant. As the pressure downstream of the turbine runner increases, the flow of atmospheric air is reduced or even stopped due to insufficient pressure differential.
  • WO 2019/179742 A1 describes a runner of a hydroelectric turbine or pump with improved level of dissolved oxygen when backpressure increases. This is achieved by altering the geometry near the trailing edge of the runner to create a local drop in pressure on the trailing edge surface.
  • the described runner comprises openings in the trailing edge surface to admit gas to the passing fluid during operation of the runner.
  • the profile of the suctions side surface at the location of the openings is concave.
  • the objective of the present invention is to specify a runner of a hydroelectric turbine or pump featuring an equal or better behavior concerning dissolved oxygen in backpressure situation having a less significant impact on performance of the runner.
  • Fig. 1 is a cross-sectional view of an axial type runner
  • Fig. 2 is a cross-sectional view of a Francis type runner
  • Fig. 3 shows a blade with means for supplying a flow of oxygen containing gas
  • Fig. 4 shows a blade with means for supplying a flow of oxygen containing gas
  • Fig. 5 shows a protrusion
  • Fig. 6 shows different types of protrusions
  • Fig. 7 shows a protrusion directly located at the trailing edge
  • Fig. 8 shows a protrusion spaced apart from the trailing edge
  • Fig. 9 shows different profiles of protrusions in y-direction
  • Fig. 10 shows the outlet diameter D for different runner types
  • Fig. 11 shows the intersection of a protrusion with an opening
  • Fig. 12 shows different arrangements of protrusions and openings
  • Fig. 13 shows different arrangements of protrusions on a wide opening.
  • Figure 1 displays schematically a cross-sectional view of an axial type runner.
  • the runner hub is designated as 1.
  • a runner blade designated as 2 extends from the hub 1.
  • the fluid flow is divided by the blade 2 whereas one side of the blade 2 forms the pressure surface and the other side the suction surface.
  • the pressure side surface is designated by 10 and the suction side surface is designated by 11.
  • Figure 2 displays schematically a cross-sectional view of a Francis type runner (only the right side is shown completely).
  • the runner crown is designated as 8.
  • a runner blade extends between the crown 8 and the band designated as 9.
  • the blade has a leading edge designated as 3 and a trailing edge designated as 4 meaning that the fluid entering the runner flows from the leading edge 3 towards the trailing edge 4.
  • Blades 2 of any type of runner are characterized by leading edge 3, trailing edge 4, pressure side surface 10 and suction side surface 11.
  • Each runner comprised a plurality of blades 2.
  • At least one of the blades 2 comprises means for supplying a flow of oxygen containing gas to the trailing edge 4of the same blade 2.
  • Figure 3 displays a blade comprising means for supplying a flow of oxygen containing gas to the trailing edge 4.
  • the means comprise a gas inlet aperture designated as 6, a gas passage designated as 5 and one or more openings in the trailing edge surface 4 to admit gas out of the gas passage 5 to the passing fluid during operation of the runner.
  • the blade shown in figure 3 comprises one single opening designated by 7.
  • Figure 4 displays a blade comprising means for supplying a flow of oxygen containing gas to the trailing edge 4 in another embodiment.
  • the blade comprises a plurality of openings. One of the openings is designated by 7. It is also possible that a blade comprises more than one separate gas passages 5. In this case each gas passage 5 has its own separate gas inlet aperture 6 and its own opening or openings 7.
  • the inventors have realized that the protrusions of the blade on or near the trailing edge are able to increase the level of dissolved oxygen and having at the same time a smaller impact on performance of the runner.
  • Figure 5 illustrates what is meant by the term protrusion.
  • the upper part of figure 5 shows a curve Z as a function of the variable x.
  • the variable x describes the arc length of a curve running along the trailing edge or in parallel to the trailing edge.
  • Z(x) is the thickness of the blade at the location denoted by x. It is clear that a protrusion is a local thickening of the blade.
  • the dashed lines indicate the borders of the protrusion. The distance between the dashed lines is the extension of the protrusion along x. The extension of the protrusion is designated by L.
  • the lower part of figure 5 shows the slope dZ(x)/dx of Z(x).
  • the protrusion starts with an inclining flank which is reflected by the slope being positive, than follows a plateau where slope is zero and finally a declining flank where the slope is negative.
  • the profile of the protrusion shown in figure 5 is just an example.
  • the profiles of protrusions can vary in a wide range which is illustrated in the following figures. For example there does not have to be a plateau and the profile can have kinks - that is the profile does not have to be smooth.
  • the thickness of blade could vary along x slowly by a small additional slope compared to the slopes shown in figure 5. That means that the baseline of the curve of the lower part of figure 5 could deviate from zero by a small amount in positive or negative direction.
  • the blade thickness Z(x) assumes at least at one of the borders a minimum value denoted by Z min and between the borders a maximal value denoted by Zmax.
  • the quotient Zmax/Zmin is a measure of the amount of the local thickening of the blade by the protrusion.
  • Figure 6 shows different embodiments of a protrusion.
  • the left part of figure 6 shows a protrusion which is established by corresponding profiles of the pressure side surface 10 and of the suction side surface 11 of the blade.
  • the profiles on the both sides don’t have to be symmetrical.
  • the right part of figure 6 shows the two limiting cases.
  • the protrusion On the upper part the protrusion is established by a corresponding profile on the pressure side surface 10 alone whereas the suction side profile is more or less flat in the region of the protrusion. On the lower part the protrusion is established by a corresponding profile on the suction side surface 11 alone whereas the pressure side profile is more or less flat in the region of the protrusion.
  • the inventors have realized that the embodiment according to the lower right part of figure 6 is especially advantageous since in this embodiment the impact on runner performance is smaller than in the other embodiments.
  • Figure 7 shows a protrusion designated by 12 which is located directly at the trailing edge 4 of a blade.
  • x runs along the trailing edge 4 as is indicated by the dashed arrowed line.
  • the extension of the protrusion 12 in the direction perpendicular to the trailing edge is designated by the letter W.
  • Figure 8 shows a protrusion 12 which is not located directly at the trailing edge 4 of a blade but spaced apart by a distance which is designated by the letter Y.
  • x runs along a curve which is spaced apart from the trailing edge 4 by Y as is indicated by the dashed arrowed line.
  • Figure 9 shows different profiles of protrusions regarded in a direction perpendicular to the trailing edge. This direction is indicated by the arrows designated by y.
  • the left side shows protrusions which are located directly at the trailing edge whereas the right side shows protrusions spaced apart from the trailing edge by the distance Y.
  • the top part of the figure shows straight profiles, the middle part shows convex profiles and the bottom part shows concave profiles.
  • the other sides of the blade could of course be optionally profiled accordingly.
  • the inventors have realized that the local character of the protrusions leads to a small or even neglectable impact on runner performance. For this reason it is advantageous when the extension L of the protrusions is smaller or equal to 10% of the developed length of the trailing edge.
  • the quotient Zmax/Zmin is smaller or equal to 2.0. It is further advantageous when the extension W in the direction perpendicular to the trailing edge is smaller than 5% of the outlet diameter of the runner and when the distance Y of the protrusion from the trailing edge is smaller than 1 % of the outlet diameter of the runner. The latter condition is obviously met in case that the protrusion is located directly at the trailing edge.
  • Figure 10 shows the outlet diameter D of a Francis type runner (top part) and an axial flow runner (lower part).
  • Figure 12 shows different arrangements of protrusions and openings.
  • the left side of the figure shows protrusions having a rounded profile whereas the left side shows protrusions having a roof shaped profile.
  • the lines (a) and (b) show arrangements where each protrusion is centered on the center of a corresponding opening.
  • the protrusions are located between the openings.
  • the arrangement is a combination of (a) and (c).
  • the protrusion can be integral to the blade body as shown in lines (a), (c) and (d) or connected to the blade body by gluing or welding or other connection means as indicated in line (b). It has to be noted that in the lines (c) and (d) protrusions intersect with more than one opening.
  • line (c) shows arrangements where two protrusions intersect with one and the same opening.
  • Figure 13 shows different arrangements of protrusions in relation to a wide opening in a similar manner as in figure 12.
  • line (a) and (b) three protrusions are distributed equally spaced along the extension of the opening. The first and last of the protrusions extent outside the borders of the opening.
  • line (c) two protrusions are located completely within the borders of the opening.
  • the arrangement is a combination of (a) and (c). It has to be noted that in the embodiments of figure 13 two or more protrusions intersect with one and the same single opening.
  • the inventors have realized that such an arrangement with several smaller protrusions intersecting with a wider opening has a very small impact on runner performance. It is further advantageous that in such an arrangement the space between two adjacent protrusions is equal or smaller than the extension L of both of the two adjacent protrusions.
  • the current patent application is also related to a method of refurbishing an existing runner wherein the runner is provided with protrusions according to the preceding paragraphs.
  • the method comprises a step of connecting one or more protrusions to the at least one blade of the runner.

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Hydraulic Turbines (AREA)

Abstract

A runner for a hydraulic turbine or pump, having an outlet diameter D and comprising a plurality of blades (2), each blade comprising a leading edge (3) and a spaced apart trailing edge (4), at least one of the blades having means for supplying a flow of oxygen containing gas to the trailing edge of the same blade whereas the means comprise a gas inlet aperture (6), a gas passage (5) and one or more openings (7), wherein the at least one of the blades comprises one or more protrusions (12), whereas the one or more protrusion is spaced apart from the trailing edge in a direction perpendicular to the trailing edge by less than 1% of the outlet diameter D, and whereas the one or more protrusion intersects with at least one of the one or more openings.

Description

Runner for a hydraulic turbine or pump
The present invention relates generally to hydroelectric turbine or pump installations. More particularly, this invention pertains to hydroelectric installations with means for enhancing the level of dissolved gas in water passing through the turbine or pump.
A significant environmental problem for many hydroelectric facilities is the water quality of discharges. Various attempts have been made to enhance the level of dissolved oxygen in discharged water of hydroelectric installations. For example, U.S. Pat. No. 5,924,842 to Beyer, James R. discloses a runner for a Francis turbine comprising a crown; a band substantially concentric with the crown; and a plurality of blades extending between crown and the band at spaced intervals along the crown, each blade fixedly secured to the crown at an inner edge and to the band at a distal outer edge, each blade having a water directing surface defined by a pressure side, an opposite facing suction side, a leading edge and a spaced apart trailing edge, at least one of the blades including: a leading edge blade portion having a rear edge in which a first slot is machined along at least a portion of the rear edge; a trailing portion having a front edge in which a second slot is machined along at least a portion of the front edge; wherein the trailing portion is fixedly secured to the leading blade portion along the front edge and the rear edge, respectively, so that the first and second channels cooperate to form an integral passage in the at least one of the blades; and means for discharging an oxygen containing gas from the integral passage to a location adjacent the trailing edge.
The objective of the mentioned state of the art is to increase the level of dissolved oxygen downstream of the turbine or pump by introducing an oxygen containing gas into the water passing through the unit. The amount of gas introduced into the water passing through the unit depends on the pressure conditions on the low-pressure side of the runner. For example when the tailwater level rises and therefore the backpressure is increased, the aeration capability of the prior art designs may become ineffective. It is common at hydropower plants that the downstream level (often referred to as tail water level) rises as more flow is passed through the turbine(s) of the hydro plant or if flow is released over an adjacent spillway. The resulting higher tail water level increases the pressure at the outlet of the turbine. In aerating turbines, the source of the oxygen containing gas is often atmospheric air in the hydro plant. As the pressure downstream of the turbine runner increases, the flow of atmospheric air is reduced or even stopped due to insufficient pressure differential.
WO 2019/179742 A1 describes a runner of a hydroelectric turbine or pump with improved level of dissolved oxygen when backpressure increases. This is achieved by altering the geometry near the trailing edge of the runner to create a local drop in pressure on the trailing edge surface. The described runner comprises openings in the trailing edge surface to admit gas to the passing fluid during operation of the runner. The profile of the suctions side surface at the location of the openings is concave.
The inventors have realized that such a profile has a negative impact on the performance of the runner.
The objective of the present invention is to specify a runner of a hydroelectric turbine or pump featuring an equal or better behavior concerning dissolved oxygen in backpressure situation having a less significant impact on performance of the runner.
The problem is solved by a runner according to the independent claim. Other favorable implementations of the invention are disclosed in the depended claims.
The invention will hereinafter be described in conjunction with the appended drawings:
Fig. 1 is a cross-sectional view of an axial type runner;
Fig. 2 is a cross-sectional view of a Francis type runner;
Fig. 3 shows a blade with means for supplying a flow of oxygen containing gas; Fig. 4 shows a blade with means for supplying a flow of oxygen containing gas; Fig. 5 shows a protrusion;
Fig. 6 shows different types of protrusions;
Fig. 7 shows a protrusion directly located at the trailing edge; Fig. 8 shows a protrusion spaced apart from the trailing edge;
Fig. 9 shows different profiles of protrusions in y-direction;
Fig. 10 shows the outlet diameter D for different runner types;
Fig. 11 shows the intersection of a protrusion with an opening; Fig. 12 shows different arrangements of protrusions and openings;
Fig. 13 shows different arrangements of protrusions on a wide opening.
Figure 1 displays schematically a cross-sectional view of an axial type runner. The runner hub is designated as 1. A runner blade designated as 2 extends from the hub 1. The fluid flow is divided by the blade 2 whereas one side of the blade 2 forms the pressure surface and the other side the suction surface. The pressure side surface is designated by 10 and the suction side surface is designated by 11.
Figure 2 displays schematically a cross-sectional view of a Francis type runner (only the right side is shown completely). The runner crown is designated as 8. A runner blade extends between the crown 8 and the band designated as 9. The blade has a leading edge designated as 3 and a trailing edge designated as 4 meaning that the fluid entering the runner flows from the leading edge 3 towards the trailing edge 4. Blades 2 of any type of runner are characterized by leading edge 3, trailing edge 4, pressure side surface 10 and suction side surface 11. Each runner comprised a plurality of blades 2. At least one of the blades 2 comprises means for supplying a flow of oxygen containing gas to the trailing edge 4of the same blade 2. Figure 3 displays a blade comprising means for supplying a flow of oxygen containing gas to the trailing edge 4. The means comprise a gas inlet aperture designated as 6, a gas passage designated as 5 and one or more openings in the trailing edge surface 4 to admit gas out of the gas passage 5 to the passing fluid during operation of the runner. The blade shown in figure 3 comprises one single opening designated by 7. Figure 4 displays a blade comprising means for supplying a flow of oxygen containing gas to the trailing edge 4 in another embodiment. The blade comprises a plurality of openings. One of the openings is designated by 7. It is also possible that a blade comprises more than one separate gas passages 5. In this case each gas passage 5 has its own separate gas inlet aperture 6 and its own opening or openings 7.
The inventors have realized that the protrusions of the blade on or near the trailing edge are able to increase the level of dissolved oxygen and having at the same time a smaller impact on performance of the runner.
Figure 5 illustrates what is meant by the term protrusion. The upper part of figure 5 shows a curve Z as a function of the variable x. The variable x describes the arc length of a curve running along the trailing edge or in parallel to the trailing edge. Z(x) is the thickness of the blade at the location denoted by x. It is clear that a protrusion is a local thickening of the blade. The dashed lines indicate the borders of the protrusion. The distance between the dashed lines is the extension of the protrusion along x. The extension of the protrusion is designated by L. The lower part of figure 5 shows the slope dZ(x)/dx of Z(x). In x-direction the protrusion starts with an inclining flank which is reflected by the slope being positive, than follows a plateau where slope is zero and finally a declining flank where the slope is negative. The profile of the protrusion shown in figure 5 is just an example. The profiles of protrusions can vary in a wide range which is illustrated in the following figures. For example there does not have to be a plateau and the profile can have kinks - that is the profile does not have to be smooth. Also the thickness of blade could vary along x slowly by a small additional slope compared to the slopes shown in figure 5. That means that the baseline of the curve of the lower part of figure 5 could deviate from zero by a small amount in positive or negative direction. In any case within a protrusion the blade thickness Z(x) assumes at least at one of the borders a minimum value denoted by Zmin and between the borders a maximal value denoted by Zmax. The quotient Zmax/Zmin is a measure of the amount of the local thickening of the blade by the protrusion. Figure 6 shows different embodiments of a protrusion. The left part of figure 6 shows a protrusion which is established by corresponding profiles of the pressure side surface 10 and of the suction side surface 11 of the blade. The profiles on the both sides don’t have to be symmetrical. The right part of figure 6 shows the two limiting cases. On the upper part the protrusion is established by a corresponding profile on the pressure side surface 10 alone whereas the suction side profile is more or less flat in the region of the protrusion. On the lower part the protrusion is established by a corresponding profile on the suction side surface 11 alone whereas the pressure side profile is more or less flat in the region of the protrusion. The inventors have realized that the embodiment according to the lower right part of figure 6 is especially advantageous since in this embodiment the impact on runner performance is smaller than in the other embodiments.
Figure 7 shows a protrusion designated by 12 which is located directly at the trailing edge 4 of a blade. In this case x runs along the trailing edge 4 as is indicated by the dashed arrowed line. The extension of the protrusion 12 in the direction perpendicular to the trailing edge is designated by the letter W.
Figure 8 shows a protrusion 12 which is not located directly at the trailing edge 4 of a blade but spaced apart by a distance which is designated by the letter Y. In this case x runs along a curve which is spaced apart from the trailing edge 4 by Y as is indicated by the dashed arrowed line.
Figure 9 shows different profiles of protrusions regarded in a direction perpendicular to the trailing edge. This direction is indicated by the arrows designated by y. The left side shows protrusions which are located directly at the trailing edge whereas the right side shows protrusions spaced apart from the trailing edge by the distance Y. The top part of the figure shows straight profiles, the middle part shows convex profiles and the bottom part shows concave profiles. The other sides of the blade could of course be optionally profiled accordingly. The inventors have realized that the local character of the protrusions leads to a small or even neglectable impact on runner performance. For this reason it is advantageous when the extension L of the protrusions is smaller or equal to 10% of the developed length of the trailing edge. To avoid cavitation on the surface of the protrusions it is further advantageous when the quotient Zmax/Zmin is smaller or equal to 2.0. It is further advantageous when the extension W in the direction perpendicular to the trailing edge is smaller than 5% of the outlet diameter of the runner and when the distance Y of the protrusion from the trailing edge is smaller than 1 % of the outlet diameter of the runner. The latter condition is obviously met in case that the protrusion is located directly at the trailing edge.
Figure 10 shows the outlet diameter D of a Francis type runner (top part) and an axial flow runner (lower part).
To establish the positive effect of a protrusion on the level of dissolved oxygen it is necessary that the protrusion 12 intersects with an opening 7. The phrase ‘intersect’ means that the extension of the protrusion 12 in x-direction has an overlap with the extension of the opening 7 in x-direction. In case that the protrusion is spaced apart from the trailing edge the condition of intersection is given, when the projection of the protrusion onto the trailing edge intersects with an opening. A limiting case of this condition is shown in figure 11. The right side border of the protrusion 12 coincides with the left side border of the opening 7. The mentioned borders are indicated by the dashed line. The other limiting case can be obviously obtained by mirroring figure 11 on the dashed line.
Figure 12 shows different arrangements of protrusions and openings. The left side of the figure shows protrusions having a rounded profile whereas the left side shows protrusions having a roof shaped profile. The lines (a) and (b) show arrangements where each protrusion is centered on the center of a corresponding opening. In line (c) the protrusions are located between the openings. In line (d) the arrangement is a combination of (a) and (c). The protrusion can be integral to the blade body as shown in lines (a), (c) and (d) or connected to the blade body by gluing or welding or other connection means as indicated in line (b). It has to be noted that in the lines (c) and (d) protrusions intersect with more than one opening. Also has to be noted that line (c) shows arrangements where two protrusions intersect with one and the same opening. Figure 13 shows different arrangements of protrusions in relation to a wide opening in a similar manner as in figure 12. In line (a) and (b) three protrusions are distributed equally spaced along the extension of the opening. The first and last of the protrusions extent outside the borders of the opening. In line (c) two protrusions are located completely within the borders of the opening. In line (d) the arrangement is a combination of (a) and (c). It has to be noted that in the embodiments of figure 13 two or more protrusions intersect with one and the same single opening. The inventors have realized that such an arrangement with several smaller protrusions intersecting with a wider opening has a very small impact on runner performance. It is further advantageous that in such an arrangement the space between two adjacent protrusions is equal or smaller than the extension L of both of the two adjacent protrusions.
The current patent application is also related to a method of refurbishing an existing runner wherein the runner is provided with protrusions according to the preceding paragraphs. The method comprises a step of connecting one or more protrusions to the at least one blade of the runner.
List of references
1 Hub
2 Blade 3 Leading edge
4 Trailing edge
5 Gas passage
6 Inlet aperture
7 Opening 8 Crown
9 Band
10 Pressure side surface
11 Suction side surface
12 Protrusion

Claims

Claims
1. A runner for a hydraulic turbine or pump, having an outlet diameter D and comprising a plurality of blades (2), each blade (2) being defined by a pressure surface (10), an oppositely facing suction surface (11), a leading edge (3) and a spaced apart trailing edge (4), at least one of the blades (2) having means for supplying a flow of oxygen containing gas to the trailing edge (4) of the same blade (2) whereas the means comprise a gas inlet aperture (6), a gas passage (5) and one or more openings (7) in the trailing edge surface (4) to admit gas out of the gas passage (5) to the passing fluid during operation of the runner, characterized in that the at least one of the blades (2) comprises one or more protrusions (12), whereas the one or more protrusion (12) is spaced apart from the trailing edge (4) of the same blade (2) in a direction perpendicular to the trailing edge by less than 1 % of the outlet diameter D, and whereas the one or more protrusion (12) intersects with at least one of the one or more openings (7).
2. A runner for a hydraulic turbine or pump according to claim 1 , wherein the at least one of the blades (2) comprises more than one protrusion (12), whereas at least two of the protrusions (12) intersect with one and the same opening (7) of the one or more openings (7).
3. A runner for a hydraulic turbine or pump according to claim 1 or 2, wherein an extension L of the one or more protrusion (12) along x is smaller or equal to 10% of a developed length of the trailing edge (4) of said blade (2), and wherein x is the arc length of a curve running along the trailing edge (4) or in parallel to the trailing edge (4).
4. A runner for a hydraulic turbine or pump according to claim 2 and 3, wherein the space between two adjacent protrusions (12) intersecting with one and the same opening (7) is equal or smaller than the extension L of both of the two adjacent protrusions (12).
5. A runner for a hydraulic turbine or pump according to one of the preceding claims, wherein a quotient Zmax/Zmin is smaller or equal to 2.0, and wherein Zmax is the maximal value of the blade thickness and Zmin is the minimal value of the blade thickness at the one or more protrusion (12).
6. A runner for a hydraulic turbine or pump according to one of the preceding claims, wherein an extension of the one or more protrusion (12) in the direction perpendicular to the trailing edge (4) W is smaller than 5% of the outlet diameter D of the runner.
7. A runner for a hydraulic turbine or pump according to one of the preceding claims, wherein the one or more protrusion (12) is established by a corresponding profile on the suction side surface (11) alone.
8. A runner for a hydraulic turbine or pump according to one of the preceding claims, wherein the one or more protrusion (12) is integral to said blade (2).
9. A runner for a hydraulic turbine or pump according to one of claims 1 to 7, wherein the one or more protrusion (12) is connected to said blade (2).
10. A method of refurbishing an existing runner of a hydraulic turbine or pump, wherein the runner has an outlet diameter D and comprises a plurality of blades (2), each blade (2) being defined by a pressure surface (10), an oppositely facing suction surface (11), a leading edge (3) and a spaced apart trailing edge (4), at least one of the blades (2) having means for supplying a flow of oxygen containing gas to the trailing edge (4) of the same blade (2) whereas the means comprise a gas inlet aperture (6), a gas passage (5) and one or more openings (7) in the trailing edge surface (4) to admit gas out of the gas passage (5) to the passing fluid during operation of the runner, characterized in that the method comprises a step of connecting one or more protrusions (12) to the at least one blade (2) of the runner in a way to establish, that the one or more protrusion (12) is spaced apart from the trailing edge in a direction perpendicular to the trailing edge by less than 1 % of the outlet diameter D, and that the one or more protrusion (12) intersects with at least one of the one or more openings (7).
PCT/EP2021/085817 2021-02-11 2021-12-15 Runner for a hydraulic turbine or pump WO2022171336A1 (en)

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS51337U (en) * 1974-06-19 1976-01-06
US5924842A (en) 1996-10-17 1999-07-20 Voith Hydro, Inc. Hydraulic turbine for enhancing the level of dissolved gas in water
CA2389763A1 (en) * 2002-06-12 2003-12-12 Alstom Canada Inc. Hydraulic turbine with aeration by intermediate belt
WO2018137821A1 (en) * 2017-01-24 2018-08-02 Voith Patent Gmbh Radial flow runner for a hydraulic machine
WO2019179742A1 (en) 2018-03-22 2019-09-26 Voith Patent Gmbh Runner for a hydraulic turbine or pump and method of manufacturing

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS51337U (en) * 1974-06-19 1976-01-06
US5924842A (en) 1996-10-17 1999-07-20 Voith Hydro, Inc. Hydraulic turbine for enhancing the level of dissolved gas in water
CA2389763A1 (en) * 2002-06-12 2003-12-12 Alstom Canada Inc. Hydraulic turbine with aeration by intermediate belt
WO2018137821A1 (en) * 2017-01-24 2018-08-02 Voith Patent Gmbh Radial flow runner for a hydraulic machine
WO2019179742A1 (en) 2018-03-22 2019-09-26 Voith Patent Gmbh Runner for a hydraulic turbine or pump and method of manufacturing

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