Runner blade, runner and pump-turbine

Abstract

The application relates to a runner blade, a runner and a pump-turbine, the runner blade is applied to the pump-turbine, and the runner blade comprises a high-pressure head part, a blade body and a low-pressure head part which are sequentially connected, wherein along the extension direction of the camber line of the runner blade, the thickness of the high-pressure head part first increases and then decreases with the low-pressure head part being approached. The runner blade with the high-pressure head part structure can effectively reduce the pressure pulsation amplitude of the no-blade area of the pump-turbine under part load working conditions.

Description

Technical Field

[0001] This application relates to the field of water pump turbine technology, and in particular to a runner blade, a runner, and a water pump turbine. Background Technology

[0002] A pump-turbine is a reversible hydraulic machine that can operate as either a turbine or a pump. In turbine mode, it uses the energy of flowing water to drive a generator; in pump mode, it uses an electric motor to pump water from a lower elevation to a higher one, thus storing hydroelectric energy.

[0003] The pump-turbine is a core component of a pumped-storage power station, and its hydraulic stability directly affects the safe and stable operation of the station. During pump-turbine operation, the pressure fluctuation of the fluid between the moving guide vanes and the runner blades is called pressure pulsation in the bladeless region, and the magnitude of this pressure fluctuation can be characterized by its amplitude. In related technologies, the amplitude of pressure pulsation in the bladeless region under partial load conditions is relatively large, which can easily lead to instability in the pump-turbine's operation. Summary of the Invention

[0004] This application provides a turbine blade, a turbine runner, and a water pump turbine to reduce the pressure pulsation amplitude in the bladeless zone of the turbine under partial load.

[0005] To achieve the above objectives, according to a first aspect of this application, a runner blade is provided for use in a water pump turbine. The runner blade includes a high-pressure head, a blade body, and a low-pressure head connected in sequence. The thickness of the high-pressure head first increases and then decreases as it approaches the low-pressure head, along the extension direction of the blade's rib line.

[0006] Optionally, the thickness of the high-voltage head Satisfying Equation 1:

[0007] (Formula 1)

[0008] Where k is the control coefficient, and L is the total length of the blade skeleton. Let e ​​be the length of the bone line corresponding to a point on the bone line of the high-pressure head, and e is a natural constant.

[0009] Optionally, the control coefficient k is positively correlated with the rated head.

[0010] Optionally, the control coefficient k is related to the rated head. The relationship satisfies equation two:

[0011] (Formula 2)

[0012] Optionally, the total length of the bone line of the high-pressure head The ratio of the length of the blade to the total length L of the blade is between 0.065 and 0.08.

[0013] Optionally, the total length of the bone line of the high-pressure head It is positively correlated with the value of the water head section.

[0014] Optionally, the impeller blade includes a positive pressure surface and a back pressure surface, and the thickness distribution of the positive pressure surface and the back pressure surface is the same.

[0015] According to a second aspect of this application, a rotor is provided, comprising rotor blades as described above.

[0016] Optionally, the wheel further includes an upper crown and a lower ring, the wheel blades are installed between the upper crown and the lower ring, and / or there are multiple wheel blades, the multiple wheel blades are symmetrically distributed around the rotation axis of the wheel.

[0017] According to a third aspect of this application, a water pump turbine is provided, including the impeller blades or impeller as described above.

[0018] The turbine runner blade of this embodiment includes a high-pressure head, a blade body, and a low-pressure head connected in sequence. Along the extension direction of the blade's rib, the thickness of the high-pressure head first increases and then decreases as it approaches the low-pressure head. A turbine runner blade with this high-pressure head structure can effectively reduce the amplitude of pressure pulsation in the bladeless region during partial load operation of the turbine.

[0019] Other features and advantages of this application will be described in detail in the following detailed description section. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] To gain a more complete understanding of this application and its beneficial effects, the following description will be provided in conjunction with the accompanying drawings, wherein the same reference numerals in the following description denote the same parts.

[0022] Figure 1 This is a schematic diagram of the cross-section of the impeller blade along the streamline direction provided in an exemplary embodiment of this disclosure;

[0023] Figure 2 yes Figure 1 An enlarged schematic diagram of part A in the middle;

[0024] Figure 3 This is a schematic diagram of the structure of the wheel provided in an exemplary embodiment of this disclosure;

[0025] Figure 4 This is a schematic diagram of the structure for removing the upper crown using a rotating wheel, provided in an exemplary embodiment of this disclosure;

[0026] Figure 5 This is a comparison chart of the pressure pulsation amplitude in the bladeless zone of a pump-turbine with the runner blades of this application and a pump-turbine with conventional blades under the turbine operating condition provided in the exemplary embodiments of this disclosure.

[0027] Figure 6 This is data showing the variation of blade thickness of the impeller blades with the length of the rib line of the high-pressure head in the exemplary embodiments of this disclosure;

[0028] Figure 7 This is a graph showing the variation of the blade thickness of the impeller blades with the length of the rib line of the high-pressure head in an exemplary embodiment of this disclosure.

[0029] Explanation of reference numerals in the attached figures:

[0030] Runner 10, upper crown 11, lower ring 13, runner blade 15, high pressure head 151, blade body 153, low pressure head 155, positive pressure surface 157, negative pressure surface 159, runner blade rib line 152. Detailed Implementation

[0031] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the protection scope of this application.

[0032] A pump-turbine is a reversible hydraulic machine that can operate as either a turbine or a pump. In turbine mode, it uses the energy of flowing water to drive a generator; in pump mode, it uses an electric motor to pump water from a lower elevation to a higher one, thus storing hydroelectric energy.

[0033] Pump-turbines are the core component of pumped-storage power stations, and their hydraulic stability directly affects the safe and stable operation of the station. During pump-turbine operation, the pressure fluctuation of the fluid between the moving guide vanes and the runner blades is called bladeless pressure pulsation, and its magnitude can be characterized by the pressure pulsation amplitude. Compared to pump operation, the pressure pulsation amplitude in the bladeless region under partial load is relatively large in turbine operation, which is one of the important factors causing instability in pump-turbine operation. Reducing the pressure pulsation amplitude in the bladeless region under partial load in turbine operation is one of the main goals of pump-turbine development.

[0034] To reduce the amplitude of pressure pulsation in the bladeless region during partial load operation of a water turbine, this application provides a runner blade 15 for use in a water pump turbine. The runner blade 15 includes a high-pressure head 151, a blade body 153, and a low-pressure head 155 connected in sequence. Along the extension direction of the blade's rib 152, the thickness of the high-pressure head 151 first increases and then decreases as it approaches the low-pressure head 155.

[0035] Please combine Figure 1 It can be seen that the extension direction of the blade rib 152 can be: from the high pressure head 151, through the blade body 153, to the low pressure head 155.

[0036] It should be noted that the skeletal line 152 of the runner blade can be the centerline of the cross-sectional shape of the runner blade 15 along the streamline direction. Corresponding to the three parts of the runner blade 15: the high-pressure head 151, the blade body 153, and the low-pressure head 155, the skeletal line 152 of the runner blade includes three parts: the skeletal line of the high-pressure head 151, the skeletal line of the blade body 153, and the skeletal line of the low-pressure head 155.

[0037] In this embodiment, the main improvement lies in the high-pressure head 151 of the rotor blade 15. The rib of the high-pressure head 151 can be the centerline of the cross-sectional shape of the high-pressure head 151 along the streamline direction. The rib of the high-pressure head 151 can include the starting point Q1 and the ending point Q2 of the high-pressure head 151. The extending direction of the rib 152 of the rotor blade can be from the starting point Q1 to the ending point Q2 of the high-pressure head 151.

[0038] Along the extension direction of the blade rib 152, the thickness of the high-pressure head 151 first increases and then decreases as it approaches the low-pressure head 155. In other words, from the starting point Q1 to the ending point Q2 of the high-pressure head 151, the thickness of the high-pressure head 151 first increases and then decreases. The runner blade 15 with this high-pressure head 151 structure can effectively reduce the pressure pulsation amplitude in the bladeless region of the pump-turbine under partial load conditions. Furthermore, the runner blade of this application can reduce the pressure pulsation amplitude in the bladeless region of the partial load conditions of the pump-turbine without causing significant adverse effects on the pump operation.

[0039] In some examples, the thickness of the high-pressure head 151 can specifically refer to the thickness of the cross section perpendicular to the bone line direction of the high-pressure head 151.

[0040] In some examples, the high-pressure head 151 of the rotor blade 15 can be designed in a snake-head shape, so that the thickness of the high-pressure head 151 first increases and then decreases.

[0041] Furthermore, the thickness of the high-pressure head of the rotor blade 15 satisfy:

[0042] (Formula 1)

[0043] In Equation 1, the blade thickness of the rotor blade 15 is given. With the length of the skeletal line of the high-pressure head 151 The relationship of change. In Equation 1, k is the control coefficient, and L is the total length of the blade rib 152. This refers to the length of the bony line corresponding to a point on the bony line of the high-pressure head 151, or more specifically, the length of the bony line of the high-pressure head corresponding to a point on the bony line of the high-pressure head. The specific calculation method can be: the length of the bone line between a certain point on the bone line of the high-pressure head 151 and point Q1.

[0044] For a single rotor blade 15, the total length L of the blade's rib 152 is a constant. The value of may vary; please refer to [link / reference]. Figure 1 and Figure 2 Point Q1 is the starting point (or apex) of the high-pressure head 151, and point Q2 is the ending point of the high-pressure head 151. At the starting point of the high-pressure head 151, i.e., point Q1, the bone line length of the high-pressure head 151 is 0. The bone line length of the high-pressure head 151 corresponding to point Q1 is... The value is 0. Along the extension direction of the rib line 152 of the impeller blades, the length of the rib line of the high-pressure head 151 gradually increases as it approaches the low-pressure head 155. It gradually gets bigger.

[0045] This represents the total length of the bony line of the high-pressure head. In one example, when the bony line of the high-pressure head 151 extends to point Q2 (where Q2 is the endpoint of the bony line of the high-pressure head 151), the length of the bony line of the high-pressure head 151 corresponding to point Q2 is... It is the length of the bony line between points Q2 and Q1, and the length of the bony line of the high-pressure head 151 corresponding to point Q2. Total length of the bone line of the high-pressure head 151 Equal, in other words, at point Q2, and The values ​​are equal. Please combine... Figure 2 For ease of understanding, Figure 2 The total length of the bony line of the high-pressure head 151 is marked out in the example. , Similarly, this can be the length of the bony line between points Q2 and Q1. It's important to note that the bony line between points Q2 and Q1 is actually a curve; please refer to [link to documentation] for details on the bony line between points Q2 and Q1. Figure 2 The double-dotted section (or the red line section). In practice, it can be the length of the double-dotted line (or the red line) between points Q2 and Q1. The double-dotted line (or the red line) is only used to illustrate the bone line between points Q2 and Q1, and does not mean that the impeller blade of this application necessarily has this physical line.

[0046] e is a natural constant with a value of approximately 2.71828.

[0047] Furthermore, k can be the rated head of the power station used with the runner blade 15. The relevant control coefficients, when the turbine blades are 15, are applied to the power station's rated head. Once determined, the value of k is also determined.

[0048] Among them, the control coefficient k is related to the rated head of the power station. They are positively correlated. In some implementations, the control coefficient k is positively correlated with the rated head. The relationship satisfies:

[0049] (Formula 2)

[0050] The rated head of the power station is used for the turbine runner blade 15. Rated head is an important parameter of a hydropower station. It refers to the minimum head required for the pump-turbine to generate rated power at rated speed.

[0051] In simple terms, head refers to the difference in water level between upstream and downstream, which is the energy source from which the potential energy of the water flow is converted into the mechanical energy of the turbine. The turbine blades 15 are used in power plants to measure the rated head. Once determined, the rated head will be... Substituting the value of into Equation 2, we can obtain the value of the control coefficient k. Substituting the value of the control coefficient k into Equation 1, we can obtain the blade thickness of the rotor blade 15 in this scenario. The relationship between the length of the rib of the high-pressure head 151 and the specific parameters of the runner blade 15 can be obtained. It is easy to understand that the runner blade 15 of this application can be applied to different scenarios. For example, the power station in scenario one can have a first rated head, and the power station in scenario two can have a second rated head. When the first rated head is greater than the second rated head, then according to equation two, the control coefficient k of the power station in scenario one is greater than the control coefficient k of the power station in scenario two. It can be seen from equations one and two that the higher the rated head, or the larger the rated head, the thicker the overall thickness of the high-pressure head 151 of the runner blade 15.

[0052] In one example, when the rated head When the value is 400m, substituting into Equation 2, we get k = 89.64. Substituting the value of the control coefficient k into Equation 1, the total length L of the blade rib 152 in Equation 1 is 2600mm. When the length of the blade rib of the high-voltage head 151 is... When the value is 200mm, The ratio of L to 0.077 is equal to the blade thickness of rotor blade 15. It measures 80.917mm. For more detailed parameters, please refer to [link / reference needed]. Figure 6 , Figure 6 Table (b) is a continuation of Table (a). According to... Figure 6 Please refer to the charts drawn from the numerical values ​​in the chart. Figure 7 . Figure 7 In the middle, the rated head The value of is 400m, the value of k is 89.64, the total length of the skeletal line 152 of the rotor blade is 2600mm, and the total length of the skeletal line of the high-voltage head 151 is... The value is 200mm. Figure 7 The diagram illustrates the blade thickness of the runner blades under the aforementioned conditions. With the length of the skeletal line of the high-pressure head 151 A changing table. In Figure 7It can be seen that, with the length of the bone line... The thickness of the blades in section 151 of the high-pressure head increases first and then decreases.

[0053] Please combine Figure 2 For ease of understanding, Figure 2 The image exemplarily illustrates the blade thickness of runner blade 15 at point Q3 on the blade's skeletal line. The length of the bone line at point Q3 corresponding to the high-pressure head 151 It can be the length of the bone line between points Q3 and Q1.

[0054] The turbine runner blade 15 proposed in this application is related to the head section to which it is applied, and is applicable to units with different head sections. Compared to conventional turbine runner blades (i.e., pump-turbine runners with conventional airfoil heads), when the pump-turbine is in turbine operating condition, the turbine runner blade 15 proposed in this application can suppress unstable vortices within the bladeless region of the turbine under partial load conditions, improve the flow regime, and thus reduce the pressure pulsation amplitude in the bladeless region of the partial load area, thereby improving hydraulic stability. Please refer to... Figure 5 , Figure 5 The diagram illustrates the comparative results of pressure pulsation amplitude in the bladeless region when the pump-turbine is in turbine operation, obtained through model tests. The comparison objects are a pump-turbine with conventional runner blades and a pump-turbine with the runner blade 15 of this application. Figure 5 It can be seen that the two curves of the two compared objects have two intersection points, P1 and P2. In the operating condition between P1 and P2, the pressure pulsation amplitude in the bladeless region of the pump-turbine with the impeller blades 15 of this application is significantly reduced compared to the pressure pulsation amplitude in the bladeless region of the pump-turbine with conventional impeller blades. This demonstrates that the pump-turbine with the impeller blades 15 of this application can significantly improve the pressure pulsation in the bladeless region of the turbine. For example, please refer to... Figure 5 When the turbine output is between 20% and 60%, the amplitude of the pressure pulsation in the bladeless region of the pump-turbine with the runner blades 15 of this application is smaller than that of the pump-turbine with conventional runner blades. In other words, the embodiments of this application can reduce the amplitude of the pressure pulsation in the bladeless region during partial load and improve hydraulic stability. For example, when the turbine output is around 38%, it can be seen that the amplitude of the pressure pulsation in the bladeless region of the pump-turbine with the runner blades 15 of this application is significantly lower than that of the pump-turbine with conventional airfoil-shaped head blades.

[0055] In some embodiments, the total length of the bone line of the high-pressure head 151 The ratio of the total length L of the ribs 152 of the impeller blades to the total length L of the impeller blades ranges from 0.065 to 0.08. For example, the total length of the ribs of the high-pressure head 151... The ratio of the length of the blade to the total length L of the blade's rib 152 can be 0.065, 0.07, or 0.08.

[0056] In some implementations, please refer to Figure 1 and Figure 2 , Figure 1 and Figure 2 Total length of the skeletal line in the medium-high pressure head 151 That is Figure 1 The total length of the bone line between Q1 and Q2. Q1 is the starting point of the high-pressure head 151, Q2 is the connection point between the high-pressure head 151 and the blade body 153, and Q2 is the ending point of the high-pressure head 151. Figure 1 and Figure 2 Total length of the skeletal line in the medium-high pressure head 151 The value is 200mm, the total length L of the blade rib 152 is 2600mm, and the total length of the rib of the high-voltage head 151 is... The ratio of the length L of the blade skeletal line 152 to the total length L is 0.077.

[0057] In some embodiments, the total length of the bone line of the high-pressure head 151 It is positively correlated with the value of the head section. In other words, the higher the head section of the power station where the runner blade 15 is applied, the better. The larger the value, the better.

[0058] In one example, the length of the high-pressure head bone line Values ​​range from 0 to ,in = (0.065~0.08)L, the value is positively correlated with the water head.

[0059] In some embodiments, the total length of the bone line of the high-pressure head 151 It is positively correlated with the head section. In other words, the higher the head section of the power station where the turbine blades are used, the better. The larger the value, the greater the total length of the bone line in the high-pressure head 151. The ratio of the length of the blade to the total length L of the blade's rib 152 ranges from 0.065 to 0.08.

[0060] In some embodiments, the impeller blade 15 may include a positive pressure surface 157 and a back pressure surface 159, wherein the positive pressure surface 157 and the back pressure surface 159 have the same thickness distribution.

[0061] Among them, the positive pressure surface 157, also known as the pressure surface, is the side with relatively high water flow pressure when the water pump turbine is running. The back pressure surface 159, also known as the suction surface, is the side with relatively low water flow pressure.

[0062] Please combine Figure 1 and Figure 2 , Figure 1 The diagram shows the position of the skeletal line 152 of the rotor blade. The skeletal line 152 of the rotor blade can be the centerline of the cross-sectional shape of the rotor blade 15 along the streamline direction. Figure 1 The skeletal line 152 of the rotor blade is a curve. A perpendicular line is drawn from any point on the skeletal line 152. The distance from this perpendicular line from the skeletal line 152 to the positive pressure surface 157 is equal to the distance from the skeletal line 152 to the negative pressure surface 159. The distance from this perpendicular line from the skeletal line 152 to the positive pressure surface 157 is the thickness of the positive pressure surface 157. The distance from this perpendicular line from the skeletal line 152 to the negative pressure surface 159 is the thickness of the negative pressure surface 159. For example, please refer to... Figure 1 Take a point M on the skeletal line 152 of the rotor blade and draw a perpendicular line L to the skeletal line 152 of the rotor blade. The intersection of this perpendicular line L with the positive pressure surface 157 is point P, and the intersection of this perpendicular line L with the negative pressure surface 159 is point N. The distance between point M and point P is equal to the distance between point M and point N.

[0063] Secondly, please combine Figure 3 This application also provides a rotor 10, which includes the rotor blades 15 described above. Since the rotor 10 includes the rotor blades 15 described above, the rotor has all the beneficial effects of the rotor blades 15 described above, which will not be repeated here.

[0064] Please combine Figure 4 In some embodiments, the wheel further includes an upper crown 11 and a lower ring 13, with the wheel blades 15 mounted between the upper crown 11 and the lower ring 13. There may be multiple wheel blades 15, symmetrically distributed around the rotation axis of the wheel. Alternatively, the multiple wheel blades 15 may be symmetrically distributed around the center of the rotation axis of the wheel.

[0065] In some examples, the upper crown 11, the lower ring 13, and multiple impeller blades 15 can be symmetrical about the axis of rotation.

[0066] Thirdly, this application also provides a water pump turbine, which includes the aforementioned impeller blades 15 or the aforementioned impeller 10. This water pump turbine possesses all the beneficial effects of the aforementioned impeller blades 15 or the aforementioned impeller 10, which will not be elaborated upon here.

[0067] In the description of this application, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more features. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0068] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0069] The embodiments, implementation methods, and related technical features of this application can be combined and substituted for each other without conflict.

[0070] The above are merely preferred embodiments of this application and are not intended to limit this application in any way. Any modifications, equivalent changes, or alterations made to the above embodiments based on the technical essence of this application without departing from the scope of the technical solution of this application shall still fall within the scope of the technical solution of this application.

Claims

1. A rotor blade, characterized in that, Applied to water pump turbines, the runner blades include a high-pressure head, a blade body, and a low-pressure head connected in sequence. Along the extension direction of the blade rib, the thickness of the high-pressure head first increases and then decreases as it approaches the low-pressure head. The thickness of the high-pressure head Satisfying Equation 1: Where k is the control coefficient, and L is the total length of the blade skeleton. Let be the length of the bony line corresponding to a point on the bony line of the high-pressure head, and e be the natural constant. The control coefficient k is positively correlated with the rated head.

2. The impeller blade according to claim 1, characterized in that, The control coefficient k is related to the rated head. The relationship satisfies equation two: 。 3. The impeller blade according to claim 1, characterized in that, The total length of the bone line in the high-pressure head The ratio of the length of the blade to the total length L of the blade is between 0.065 and 0.

08.

4. The impeller blade according to any one of claims 1 to 3, characterized in that, The total length of the bone line in the high-pressure head It is positively correlated with the value of the water head section.

5. The impeller blade according to any one of claims 1 to 3, characterized in that, The impeller blade includes a positive pressure surface and a negative pressure surface, and the thickness distribution of the positive pressure surface and the negative pressure surface is the same.

6. A rotary wheel, characterized in that, The impeller includes impeller blades as described in any one of claims 1 to 5.

7. The impeller according to claim 6, characterized in that, The impeller further includes an upper crown and a lower ring, and the impeller blades are mounted between the upper crown and the lower ring; and / or The rotor blades are multiple, and the multiple rotor blades are symmetrically distributed around the rotation axis of the rotor.

8. A water pump turbine, characterized in that, It includes the impeller blades as described in any one of claims 1 to 5, or the impeller as described in claim 6 or 7.

Images