Design method for side water inlet and outlet of pumped storage power station based on minimum hydraulic loss

Abstract

The invention relates to the technical field of pumped storage power station side water inlets and outlets, in particular to a pumped storage power station side water inlet and outlet design method based on minimum hydraulic loss, which comprises the following steps: dividing a side water inlet and outlet into a transition section, a diffusion section, an adjusting section and an anti-vortex beam section along a water flow direction, wherein the diffusion section is further divided into a front section, a middle section and a tail section. The method comprises the following steps: setting key shape parameters of a diffusion section and an anti-vortex beam section, designing shapes of a middle pier and a side pier to optimize flow distribution of each flow channel, respectively calculating along-way hydraulic loss and local hydraulic loss of each section, taking minimization of a total hydraulic loss coefficient of the whole flow channel as an optimization target, and optimizing the flow distribution of each flow channel under the constraint of following engineering specifications and a reasonable parameter design domain. According to the method, the energy loss in the water delivery process of the power station can be reduced, the energy conversion efficiency under the water pumping and power generation working conditions is improved, meanwhile, the water flow state is optimized, and the safety risks such as unit vibration and cavitation erosion damage are reduced.

Description

Technical Field

[0001] This invention belongs to the technical field of side-type inlet and outlet of pumped storage power stations, specifically relating to a design method for side-type inlet and outlet of pumped storage power stations based on minimum hydraulic loss. Background Technology

[0002] As the global energy structure accelerates its transition to clean and low-carbon energy, the large-scale grid connection of renewable energy places unprecedented demands on the flexibility and regulation capabilities of power systems. Pumped storage power stations, with their significant advantages such as large capacity, long-term energy storage, rapid response, and mature technology, play a crucial role in peak shaving, valley filling, frequency and phase regulation, and emergency backup. A pumped storage power station generally consists of an upper reservoir, a lower reservoir, a water conveyance system, and a power plant.

[0003] Because the direction, velocity, and distribution of water flow change drastically in the inlet and outlet areas (such as contraction, diffusion, and reversal), this area becomes one of the most concentrated and significant local head losses in the entire water conveyance system. The total hydraulic loss at the inlet / outlet has a significant impact on the efficiency of pumped storage power stations.

[0004] Currently, the design of side-mounted inlet / outlet pumped storage power stations built both domestically and internationally is largely constrained by factors such as construction difficulty and local geology, making it difficult to minimize hydraulic losses during the design process. Furthermore, hydraulic losses are often accompanied by undesirable flow patterns (such as vortices, backflow, flow separation, and asymmetric flow): strong vortices may lead to air intake, causing unit vibration, efficiency reduction, and even cavitation damage; backflow and flow separation may cause structural vibration, cavitation erosion, and further affect the safe and stable operation of the power station.

[0005] In view of this, the present invention is hereby proposed. Summary of the Invention

[0006] To address the aforementioned technical problems in the existing technology, this invention provides a design method for the side-type inlet and outlet of a pumped storage power station based on minimizing hydraulic loss. This method more effectively utilizes the effective head to increase power generation output, while reducing energy consumption during pumping to transport water to the same height, thereby improving the power station's operating efficiency. Furthermore, by minimizing hydraulic loss and optimizing the flow pattern, it significantly reduces the safety risks caused by unfavorable flow patterns.

[0007] To achieve the above objectives, the technical solution of the present invention is as follows:

[0008] A design method for side-type inlet and outlet of pumped storage power stations based on minimum hydraulic loss, characterized by including: S1. The side inlet and outlet are divided into a transition section, a diffusion section, an adjustment section and an anti-vortex beam section along the water flow direction. The diffusion section includes a front section, a middle section and a final section. S2. Set the horizontal diffusion angle, the middle wall setback distance, and the top plate elevation angle of the diffusion section; set the width of the piers in the middle and end sections of the diffusion section to be equal; set the number of beams, beam width, and beam spacing of the anti-vortex beam section. S3. Set the shape of the middle pier and the side pier to adjust the effective flow area of ​​each flow channel, so that the uneven flow distribution of each flow channel is controlled within the preset range. S4. Calculate the friction loss and local hydraulic loss of the transition section, diffusion section, adjustment section and anti-vortex beam section respectively; S5. Taking the minimization of the total hydraulic loss coefficient of the entire flow channel of the side inlet and outlet as the optimization objective, and under the constraints of following current engineering specifications and ensuring that the body parameters of each segment are within a reasonable design domain, solve for the optimal combination of body parameters of each segment, and determine the comprehensive geometric parameters of the side inlet and outlet to achieve the theoretical minimum value of global hydraulic loss.

[0009] Furthermore, the preset range for the uneven distribution of traffic flow is no more than 10%.

[0010] Furthermore, the horizontal diffusion angle of the diffusion section ranges from 25° to 45°.

[0011] Furthermore, the setback distance of the middle wall of the diffusion section is 3~3.5m, or 1 / 2 of the inlet width of the side inlet / outlet.

[0012] Furthermore, the elevation angle of the top plate of the diffusion section ranges from [ ].

[0013] Furthermore, the anti-vortex beam segment has 3 to 5 beams, a beam width of 1.0 to 1.5 m, and a beam spacing of 0.8 to 1.5 m.

[0014] Furthermore, the width of the pier remains consistent throughout the middle section, the end section, the adjustment section, and the anti-vortex beam section of the diffusion section.

[0015] Furthermore, the calculation methods for hydraulic losses along each section include: Hydraulic loss along the transition section The formula is:

[0016] Hydraulic loss along the front section of the diffuser The formula is: (Intermediate flow channel) (Side channels)

[0017] Hydraulic loss along the middle section of the diffuser The formula is: (Intermediate flow channel) (Side channels)

[0018] Hydraulic loss along the diffusion section The formula is: (Intermediate flow channel) (Side channels)

[0019] Hydraulic loss along the adjustment section The formula is:

[0020] The total hydraulic loss along the friction length is the sum of the hydraulic losses along the friction length of each individual section. The formula is:

[0021] in, For the frictional hydraulic loss along the gradient layer L1, For the hydraulic losses along the diffusion section L2, For the hydraulic losses along the L3 diffusion section, For the hydraulic losses along the L4 diffusion section, This is to adjust the hydraulic losses along section L5.

[0022] Furthermore, the calculation methods for local hydraulic losses in each section include: Local hydraulic loss in transition section L1 The formula is:

[0023] Local hydraulic loss at the diffuser inlet The formula is:

[0024] ×

[0025]

[0026] Local hydraulic losses in diffuser sections L2, L3 and L4 The formula is:

[0027] Local hydraulic loss at the diffuser outlet The formula is:

[0028] Local hydraulic loss of anti-vortex beam section L6 The formula is:

[0029] The total local hydraulic loss is the sum of the local hydraulic losses of each part. The formula is:

[0030] in, This refers to the local hydraulic loss in the transition section L1. This refers to the local hydraulic loss in diffuser section L2. This refers to the local hydraulic loss in diffuser section L3. This refers to the local hydraulic loss in diffuser section L4. This refers to the local hydraulic loss at the inlet of the diffuser section. This refers to the local hydraulic loss at the outlet of the diffuser section.

[0031] Furthermore, the formula for the sum of the total hydraulic losses of the side-type inlet and outlet is as follows:

[0032] in, This is the sum of hydraulic losses along the entire length of the route. This is the sum of the local hydraulic losses of each part.

[0033] Compared with existing technologies, the present invention provides a design method for the side inlet and outlet of a pumped storage power station based on minimizing hydraulic loss. The method includes: dividing the side inlet and outlet into a transition section, a diffusion section, an adjustment section, and an anti-vortex beam section along the water flow direction, wherein the diffusion section is further divided into a front section, a middle section, and a final section; by setting key shape parameters for the diffusion section and the anti-vortex beam section, designing the shape of the middle and side piers to optimize the flow distribution of each channel, calculating the friction loss and local hydraulic loss of each section respectively, and taking the minimization of the overall hydraulic loss coefficient of the channel as the optimization objective, under the constraints of engineering specifications and the reasonable design domain of parameters, finding the optimal combination of shape parameters for each section. The present invention can reduce energy loss during the water conveyance process of the power station, improve the energy conversion efficiency under pumping and power generation conditions, and optimize the water flow pattern to reduce safety risks such as unit vibration and cavitation damage. Attached Figure Description

[0034] Figure 1 A flowchart illustrating the design method for the side-type inlet and outlet of a pumped storage power station provided in an embodiment of the present invention; Figure 2 A top view of a side-mounted inlet / outlet provided in an embodiment of the present invention; Figure 3 A cross-sectional view of a side-mounted inlet / outlet provided in an embodiment of the present invention; Figure 4 A schematic diagram showing the included angle of the horizontal plane of the diffusion section provided in an embodiment of the present invention; Figure 5 A schematic diagram of the wall setback distance in the diffusion section provided in an embodiment of the present invention; Figure 6 A schematic diagram showing the width of the pier provided in an embodiment of the present invention; Figure 7 A schematic diagram showing the elevation angle of the top plate of the diffuser section of the anti-vortex beam provided in an embodiment of the present invention; Figure 8 This is a schematic diagram of the anti-vortex beam spacing and beam width provided in an embodiment of the present invention. Detailed Implementation

[0035] The technical solution of the present invention will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are not all embodiments of the present invention. All other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present invention.

[0036] It should be noted that, unless otherwise specifically stated, the relative arrangement and numerical expressions of the components and steps described in these embodiments should not be construed as limiting the scope of the invention.

[0037] The following description of exemplary embodiments is merely illustrative and is not intended to limit the invention or its application or use in any way. Techniques, methods, and apparatus known to those skilled in the art may not be discussed in detail herein, but where applicable, such techniques, methods, and apparatus should be considered part of this specification.

[0038] Example 1 See Figure 1 , Figure 1 This is a flowchart of the design method for the side-type inlet and outlet of a pumped storage power station based on minimum hydraulic loss proposed in this invention. The method calculates the minimum hydraulic loss at the inlet and outlet by changing variables such as the width of the diaphragm, the elevation angle of the diffuser top plate, the setback distance of the central wall, and the design parameters of the four important structural sections of the inlet and outlet. It also aims to achieve a uniform flow distribution and avoid large velocity fluctuations. Finally, the geometric configuration parameters corresponding to the minimum energy loss are fed back to the designers, providing an important theoretical basis for the design of the structure with minimum energy loss. Specific steps may include: S1. Segmentation: Along the water flow direction (from the reservoir to the water conveyance system or from the water conveyance system to the reservoir), the side inlet and outlet are sequentially divided into a transition section L1 and a diffusion section. The diffusion section includes the adjustment section L5 and the anti-vortex beam section L6. The diffusion section comprises the front section L2, the middle section L3, and the final section L4. Because each section has a specific hydraulic function, their geometric configurations are significantly different, and the dominant changes in the flow structure and the resulting energy dissipation mechanisms are fundamentally different. Therefore, the theoretical derivation or empirical solution method for the hydraulic loss coefficient of each section must be established separately based on its unique hydrodynamic characteristics. The theoretical derivation and empirical solution method for the hydraulic function and hydraulic loss coefficient of each section specifically include: Transition section L1: smoothly transitions the cross-sectional shape of the upstream tunnel to the rectangular cross-section required for the inlet and outlet; since the transition section is a smooth transition, the hydraulic loss coefficient is solved by integral of the Fanning formula.

[0039] diffusion segment diffusion segment By diverting the flow through the pier walls, the cross-sectional area of ​​the water passage is gradually increased, which significantly reduces the water flow velocity. The hydraulic loss in the diffusion section is complex and needs to be calculated in three sections. The first section, L2, is solved by referring to the local hydraulic loss coefficient table and integrating the Fanning formula. The middle section, L3, is solved by integrating the Fanning formula and the hydraulic energy equation. The last section, L4, is solved by referring to the local hydraulic loss coefficient table and integrating the Fanning formula.

[0040] Adjustment section L5: Its main function is to further adjust the water flow after the diffusion section and eliminate the uneven flow that may be generated by diffusion. The adjustment section is a rectangular pipe with a constant diameter. The hydraulic loss coefficient is solved by combining Chezy's formula and Darcy's formula.

[0041] Anti-vortex beam section L6: By setting a beam grid structure at the top of the water inlet, the air intake vortex on the water surface is destroyed, preventing air from entering the water supply system and ensuring the safe operation of the unit; the anti-vortex beam section is shorter than other sections, and the hydraulic loss coefficient is obtained through the common local hydraulic loss coefficient table.

[0042] Specifically, the spatial location, connection relationship, and corresponding labels of each segment can be clearly defined through the top view and sectional view, including: See Figure 2 The figure shows a top view of a side-mounted inlet / outlet. Along the water flow direction from left to right (or from the reservoir area to the water conveyance system), the sections are labeled as transition section L1, diffusion section, etc. (Including the front section L2, middle section L3, and final section L4), the adjustment section L5, and the anti-vortex beam section L6, each section is continuously connected in the horizontal direction. The front section L2, the middle section L3, and the final section L4 of the diffusion section are distributed sequentially along the water flow path, together forming a complete diffusion section. Flow channel; See Figure 3 , Figure 3This is a cross-sectional view of the side-mounted inlet / outlet. The cross-sectional shapes and corresponding labels of each segment can be observed vertically: the transition section L1 smoothly transitions in cross-sectional shape from top to bottom (or from the tunnel cross-section to the rectangular cross-section); the diffusion section... By tilting the top plate (corresponding to subsequent steps) The elevation angle β of the top plate of the section increases the cross-sectional area for water passage, and the cross-sectional dimensions of the adjustment section L5 are kept consistent. The beam grid structure is visible at the top of the anti-vortex beam section L6.

[0043] S2. Key parameter settings: Set the diffusion section The horizontal diffusion angle, the setback distance of the middle wall, and the elevation angle of the top plate are set; the width of the piers in the middle and end sections of the diffusion section is set to be equal; the number of beams, beam width, and beam spacing of the anti-vortex beam section are set; specifically including: S21, Diffusion Section Horizontal diffusion angle θ setting See Figure 4 Set up a diffusion section The horizontal diffusion angle is θ, with a value ranging from 25° to 45°, and the diffusion segment... The angle θ between the points of expansion along the horizontal plane is called the diffusion segment. The angle between the two side walls on the horizontal plane covers the entire horizontal diffusion range of the front section L2, the middle section L3, and the final section L4 of the diffusion segment.

[0044] The hydraulic losses at the inlet / outlet are closely related to the total diffusion angle of the diffuser section. An excessively large diffusion angle can cause the water to detach from the sidewalls, forming strong vortex and backflow zones within the diffuser section, resulting in significant local energy losses (separation losses). Conversely, an excessively small diffusion angle, while maintaining a good flow pattern and reducing separation losses, will significantly increase the length of the diffuser section, thereby increasing frictional losses and civil engineering costs. There exists an optimal total diffusion angle. scope( Usually around The optimization process balances avoiding water flow separation with limiting structural length, aiming to minimize total hydraulic losses and ensure efficient system operation.

[0045] S22, Diffusion Section Setting the setback distance L of the middle wall Set diffusion section The setback distance of the central wall is L, which is 3~3.5m or 1 / 2 of the inlet width of the side inlet / outlet. Refer to the parameter designation and location. Figure 5 As shown: Diffusion section Using the front section L2, middle section L3, and final section L4 of the diffusion segment as references, the middle wall relative to the diffusion segment is marked. The starting end (i.e. the starting end of the front section L2 of the diffusion segment) retreats by a distance of L, meaning that the central wall is not level with the starting end of the front section L2 of the diffusion segment, but retreats by a distance of L.

[0046] Optimize the orifice flow distribution under outflow conditions: If L is too small, the water flow is prone to flow separation and vortices near the middle wall, increasing the local resistance of the first section L2 of the diffuser; if L is too large, the diffusion space behind the gate pier is too wide, forming a large-scale low-pressure backflow zone, resulting in insufficient diffusion of the main flow in the middle section L3 and the last section L4 of the diffuser; a value of 3~3.5m or 1 / 2 of the inlet width can make the diffusion angle of the water flow in the L2→L3→L4 section more gentle, the flow velocity distribution more uniform, and reduce impact and separation losses.

[0047] S23, Diffusion Section Top plate elevation angle β setting Set diffusion section The elevation angle of the top plate is β, and its value range is [ For parameter labels and locations, please refer to [link / reference]. Figure 7 As shown: Diffusion section The vertical cross-section diagram shows the diffusion section. The top plate is tilted at an angle of β relative to the horizontal direction. This tilt angle covers the top plate of the front section L2, the middle section L3, and the end section L4 of the diffuser section. That is, the top plate gradually tilts upward from the starting end of L2 to the end of L4, with an tilt angle of β.

[0048] Uniform diffusion section Internal water flow velocity distribution to prevent flow separation: If The slope of the top plate is too small, making it difficult to guide water flow in the diffuser section. The upward diffusion from within results in excessively high flow velocities in the lower parts of segments L2, L3, and L4; if Excessive apex angles cause severe flow separation in sections L3 and L4, generating secondary flows and vortices, and increasing turbulent dissipation; The value of ] can avoid the above problems and ensure the diffusion segment The cross-sectional flow velocity is uniform, achieved by setting the elevation angle of the top plate inside the diffuser section of the inlet / outlet. This is to ensure a uniform distribution of water flow velocity within the diffusion section, prevent the formation of vortices, and minimize hydraulic losses within a reasonable design range.

[0049] S24, width d of the piers in the middle section L3 and the end section L4 of the diffusion segment. The width of the piers in the middle section L3 and the end section L4 of the diffusion section is set to d, and d remains consistent in L3, L4, L5 and L6. Refer to the parameter labels and positions. Figure 6As shown: Along the water flow direction, the side inlet / outlet is divided into six sections: L1, L2, L3, L4, L5, and L6. L1 represents the length of the transition section, L2 represents the length of the initial section of the diffuser, L3 represents the length of the middle section of the diffuser, L4 represents the length of the final section of the diffuser, L5 represents the length of the adjustment section, and L6 represents the length of the anti-vortex beam section. The lengths of L2, L3, and L4 are within the following ranges: diffusion segment The total length of the diffusion section is:

[0050] The width of the orifice flow channel adjustment section is D. In order to make the water flow transition smoothly during inflow and outflow without large pulsating flow velocity, the width of the partition between the central pier and the two side piers is equal in sections L3, L4, L5 and L6, and the size is d.

[0051] To ensure a smooth transition of water flow in the L3→L4→L5→L6 section: If the width of the piers is inconsistent between sections, it will cause sudden changes in flow velocity at the junctions of L3 and L4, L4 and L5, and L5 and L6, resulting in local eddies; a uniform d can ensure that the flow conditions of each channel are consistent in the L3 to L6 section, avoid large pulsating flow velocities, and reduce additional losses.

[0052] S25, Setting of anti-vortex beam segment L6 parameters (beam spacing s, beam width b, and number of beams n) Set the number of beams n for L6 to 3-5, the beam width b to approximately 1.0-1.5m, and the beam spacing s to approximately 0.8-1.5m. Refer to [reference needed] for parameter labels and positions. Figure 8 As shown: L6 is marked as connecting to L5 on the left, and the main body of L6 is on the right; the width of a single beam in the beam grid structure is b, the distance between two adjacent beams is s, and a total of n beams are arranged in L6 (arranged along the direction perpendicular to the water flow), and the beam shape coefficient κ=2.42.

[0053] Balancing vortex suppression with additional losses: The magnitude of hydraulic losses at side inlets / outlets varies depending on the values ​​of s, b, and n. Excessive s weakens vortex suppression, while insufficient s may overly restrict the flow channel, leading to excessively high local velocities and increased local losses. Excessive b increases form drag losses, while insufficient b weakens physical obstruction, making it difficult to effectively disrupt strong vortices and potentially resulting in significant vortex losses. Excessive n significantly increases the total obstruction area, increasing self-friction and form drag, while insufficient n makes it difficult to effectively disrupt strong vortices and may still result in significant vortex losses.

[0054] The formula for calculating the local hydraulic loss coefficient is:

[0055] in, For beam shape factor, The beam spacing The width of the beam. The angle between the beam and the direction of water flow. To ensure a smooth transition of water flow during inflow and outflow with minimal vortex losses, 3-5 beams are used, with a beam width of approximately 1.0-1.5m and a beam spacing of approximately 0.8-1.5m to reduce hydraulic losses.

[0056] S3. Flow distribution optimization: Set the shape of the middle block and the side block to adjust the effective flow area of ​​each flow channel, so that the unevenness of flow distribution in each flow channel is controlled within the preset range. Combination Figure 6 As indicated by the segment labels, the central pier and side piers are the key structures separating the various flow channels, and their shapes directly affect the diffuser section. The flow area of ​​each channel within the L234 section is the main source of uneven flow distribution (the channel dimensions in L5 and L6 are consistent, so their impact is negligible). If the central pier head is too sharp, it can easily lead to concentrated flow velocity in the channels on both sides of L2 (front section). If the connection between the side piers and the wall of L234 (diffusion section) is not smooth, it can easily cause local backflow in L3 (middle section). By optimizing the shape of the central and side piers (such as using rounded pier heads and smooth connection with the wall of L234 section), the effective flow area of ​​each channel in L2, L3, and L4 sections can be made more consistent, thereby controlling the uneven flow distribution within 10% and avoiding excessive differences in local hydraulic losses in L234 section due to uneven flow.

[0057] S4. Hydraulic loss calculation: Calculate the hydraulic loss of the transition section L1 and the diffusion section respectively. The hydraulic losses along the track and local hydraulic losses in adjustment section L5 and anti-vortex beam section L6; specifically including: By designing the shapes of the central and side piers to maximize the effective flow area of ​​the side openings, water is evenly distributed into each channel, controlling the flow distribution unevenness within 10% and reducing hydraulic losses. Secondly, the elevation angle of the top plate within the diffuser section of the inlet / outlet is... This is achieved by altering the flow velocity within the diffuser section of the inlet / outlet, preventing vortex formation, and reducing hydraulic losses. By designing the beam spacing *s*, beam width *b*, and number of beams *n* in the anti-vortex beam section, the generation of vortices in the inlet / outlet anti-vortex beam section is suppressed, reducing local hydraulic losses and ensuring the safe and efficient operation of the pumped storage power station. Specifically, this includes: Hydraulic loss along the transition section L1 The formula is:

[0058] in, The length of the transition segment. This is the friction loss coefficient (which varies with the diameter of the flow channel). The hydraulic diameter of the transition section. Flow velocity (bottom right corner) This indicates that the flow velocity changes with the pipe diameter, and can be written as a flow chart. (The functions are similar to those of others). It is the acceleration due to gravity; Hydraulic loss along diffuser section L2 The formula is:

[0059]

[0060]

[0061] in, The length of the front end of the diffuser section (twice because there are two pipes). The diameter of the two middle flow channels. The diameter of the two flow channels on both sides; Hydraulic loss along diffuser section L3 The formula is:

[0062]

[0063]

[0064] Where L3 is the length of the middle section of the diffusion segment; Hydraulic loss along diffuser section L4 The formula is:

[0065]

[0066]

[0067] L4 is the length of the latter part of the diffusion section; Hydraulic loss along section L5 The formula is:

[0068] in, Manning's roughness coefficient The hydraulic radius is 4 times the number of four pipes. The vortex-resistant beam section L6 mainly suffers from localized hydraulic losses, with the total friction loss being small and generally negligible. The total friction loss is the sum of the friction losses of each individual section. The formula is:

[0069] in, For the frictional hydraulic loss along the gradient layer L1, For the hydraulic losses along the diffusion section L2, For the hydraulic losses along the L3 diffusion section, For the hydraulic losses along the L4 diffusion section, This is to adjust the hydraulic losses along section L5.

[0070] Inlet / outlet diffuser section top plate elevation angle Horizontal diffusion angle The setback distance of the central pier mainly affects the hydraulic loss along the route by changing the dimensions of the inlet and outlet of each section, thereby influencing the hydraulic diameter. The magnitude of the hydraulic losses along the friction path is used to change the overall hydraulic losses. Local hydraulic losses in different sections include: Local hydraulic loss in transition section L1 The formula is:

[0071] Local hydraulic loss at the diffuser inlet The formula is:

[0072] ×

[0073]

[0074] Local hydraulic losses in diffuser sections L2-L4 The formula is:

[0075] Local hydraulic loss at the diffuser outlet The formula is:

[0076] Local hydraulic loss of anti-vortex beam section L6 The formula is:

[0077] Adjustment section L5: The pipe shape remains unchanged, and local hydraulic losses are negligible; the total local hydraulic loss is the sum of the local hydraulic losses of each section. The formula is:

[0078] in, This refers to the local hydraulic loss in the transition section L1. This refers to the local hydraulic loss in diffuser section L2. This refers to the local hydraulic loss in diffuser section L3. This refers to the local hydraulic loss in diffuser section L4. This refers to the local hydraulic loss at the inlet of the diffuser section. This refers to the local hydraulic loss at the outlet of the diffuser section; The formula for the sum of total hydraulic losses at the inlet and outlet is:

[0079] in, This is the sum of hydraulic losses along the entire length of the route. This is the sum of the local hydraulic losses of each part.

[0080] S5. Parameter optimization: Taking the minimization of the total hydraulic loss coefficient of the entire flow channel of the side inlet and outlet as the optimization objective, and under the constraints of following current engineering specifications and ensuring that the body parameters of each segment are within the reasonable design domain, the optimal combination of body parameters of each segment is solved to determine the comprehensive geometric parameters of the side inlet and outlet that achieve the theoretical minimum value of global hydraulic loss.

[0081] Inlet / outlet diffuser section top plate elevation angle Horizontal diffusion angle The setback distance of the central pier mainly affects local hydraulic losses by changing the shape of each inlet / outlet section. Sudden changes in shape alter the flow direction, increasing hydraulic losses. These areas account for a significant portion of the total hydraulic losses. Other methods include altering the lengths of the transition section, diffusion section, adjustment section, and anti-vortex beam section; the proportion of each section to the total length of the side inlet / outlet; the diffusion angle of the transition section at the inlet / outlet; and the elevation angle of the top plate within the diffusion section. Horizontal diffusion angle The calculation of the total hydraulic loss at the inlet / outlet is based on parameters such as the setback distance of the central pier, the beam spacing s, beam width b, and the number of beams n of the anti-vortex beam sections at the inlet / outlet. The minimum, specifically the formula is:

[0082] Find the total hydraulic loss for each of the transition section, diffusion section, adjustment section, and anti-vortex beam section, while minimizing the total hydraulic loss. The ratio of the minimum total hydraulic loss This allows us to determine which segment suffered the largest loss.

[0083] In summary, the present invention has the following advantages: 1. By optimizing the design of the side inlet and outlet of the pumped storage power station in sections, and by setting key parameters such as the horizontal diffusion angle of the diffusion section, the setback distance of the middle wall, the elevation angle of the top plate and the anti-vortex beam section, the total hydraulic loss of the side inlet and outlet is minimized, the energy conversion efficiency of the power station is improved, the effective head can be fully utilized to increase the power output during power generation, and the energy consumption can be reduced to transport water to the same height during pumping. 2. By destroying the water surface air intake vortex through the anti-vortex beam grid structure, combined with the design of diffusion section parameters, the water flow is prevented from leaving the sidewall and forming a low-pressure backflow zone, thus optimizing the water flow pattern, suppressing undesirable flow patterns such as vortices, backflow, and flow separation, reducing the risk of unit vibration, cavitation damage and structural cavitation, and ensuring the safe operation of the power station. 3. By adjusting the shape of the middle and side piers in the design, the effective flow area of ​​each flow channel is adjusted. Combined with the design of equal-width partition piers in the middle and end sections of the diffusion section, the unevenness of flow distribution in each flow channel is controlled within 10%, ensuring balanced unit load and stable operation of the power station.

[0084] The above specific embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to examples, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A design method for side-type inlet and outlet of a pumped storage power station based on minimum hydraulic loss, characterized in that, include: S1. The side inlet and outlet are divided into a transition section, a diffusion section, an adjustment section and an anti-vortex beam section along the water flow direction. The diffusion section includes a front section, a middle section and a final section. S2. Set the horizontal diffusion angle, the middle wall setback distance, and the top plate elevation angle of the diffusion section; set the width of the piers in the middle and end sections of the diffusion section to be equal; set the number of beams, beam width, and beam spacing of the anti-vortex beam section. S3. Set the shape of the middle pier and the side pier to adjust the effective flow area of ​​each flow channel, so that the uneven flow distribution of each flow channel is controlled within the preset range. S4. Calculate the friction loss and local hydraulic loss of the transition section, diffusion section, adjustment section and anti-vortex beam section respectively; S5. Taking the minimization of the total hydraulic loss coefficient of the entire flow channel of the side inlet and outlet as the optimization objective, and under the constraints of following current engineering specifications and ensuring that the body parameters of each segment are within a reasonable design domain, solve for the optimal combination of body parameters of each segment, and determine the comprehensive geometric parameters of the side inlet and outlet to achieve the theoretical minimum value of global hydraulic loss.

2. The design method for side-type inlet and outlet of a pumped storage power station based on minimum hydraulic loss according to claim 1, characterized in that, The preset range for the uneven distribution of the flow rate is no more than 10%.

3. The design method for side-type inlet and outlet of a pumped storage power station based on minimum hydraulic loss according to claim 1, characterized in that, The horizontal diffusion angle of the diffusion section ranges from 25° to 45°.

4. The design method for side-type inlet and outlet of a pumped storage power station based on minimum hydraulic loss according to claim 1, characterized in that, The setback distance of the middle wall of the diffusion section is 3~3.5m, or 1 / 2 of the inlet width of the side inlet / outlet.

5. The design method for side-type inlet and outlet of a pumped storage power station based on minimum hydraulic loss according to claim 1, characterized in that, The range of the elevation angle of the top plate of the diffuser section is [ ].

6. The design method for side-type inlet and outlet of a pumped storage power station based on minimum hydraulic loss according to claim 1, characterized in that, The anti-vortex beam section consists of 3 to 5 beams, with a beam width of 1.0 to 1.5 m and a beam spacing of 0.8 to 1.5 m.

7. The design method for side-type inlet and outlet of a pumped storage power station based on minimum hydraulic loss according to claim 1, characterized in that, The width of the pier remains consistent throughout the middle section, the end section, the adjustment section, and the anti-vortex beam section of the diffusion section.

8. The design method for side-type inlet and outlet of a pumped storage power station based on minimum hydraulic loss according to claim 1, characterized in that, The calculation methods for hydraulic losses along each section include: Hydraulic loss along the transition section The formula is: in, The length of the transition segment. This is the friction loss coefficient (which varies with the diameter of the flow channel). The hydraulic diameter of the transition section. For flow rate, It is the acceleration due to gravity; Hydraulic loss along the front section of the diffuser The formula is: in, The length of the front end of the diffusion section. The diameter of the two middle flow channels. The diameter of the pipe for the two flow channels on both sides. This refers to the hydraulic losses along the intermediate flow channel in the front section of the diffuser. This refers to the hydraulic losses along the flow channels on both sides of the front section of the diffuser. Hydraulic loss along the middle section of the diffuser The formula is: (Intermediate flow channel) (Side channels) Where L3 is the length of the middle section of the diffusion segment. This refers to the hydraulic losses along the intermediate flow channel in the middle section of the diffuser. This refers to the hydraulic losses along the flow channels on both sides of the middle section of the diffuser; Hydraulic loss along diffuser section L4 The formula is: Where L4 is the length of the latter part of the diffusion section. This refers to the hydraulic losses along the intermediate flow channel of the diffuser section. This refers to the hydraulic losses along the flow paths on both sides of the diffuser section; Hydraulic loss along section L5 The formula is: in, Manning's roughness coefficient The hydraulic radius; The total hydraulic loss along the friction length is the sum of the hydraulic losses along the friction length of each individual section. The formula is: in, For the frictional hydraulic losses along the gradient layer L1, For the friction loss along the diffuser section L2, For the friction loss along the diffusion section L3, For the hydraulic losses along the L4 diffusion section, This is to adjust the hydraulic losses along section L5.

9. The design method for side-type inlet and outlet of a pumped storage power station based on minimum hydraulic loss according to claim 1, characterized in that, The calculation methods for local hydraulic losses in each section include: Local hydraulic loss in transition section L1 The formula is: in, This is the local hydraulic loss coefficient. The average flow velocity, It is the acceleration due to gravity; Local hydraulic loss at the diffuser inlet The formula is: in, For the loss of flow channels on both sides, For intermediate flow channel loss, The horizontal diffusion angle, The average flow velocity; Local hydraulic losses in diffuser sections L2, L3 and L4 The formula is: in, This is the local hydraulic loss coefficient. The average flow velocity; Local hydraulic loss at the diffuser outlet The formula is: Local hydraulic loss of anti-vortex beam section L6 The formula is: in, The shape factor, The beam spacing The width of the beam. To prevent the angle between the vortex beam and the direction of water flow; The total local hydraulic loss is the sum of the local hydraulic losses of each part. The formula is: in, This refers to the local hydraulic loss in the transition section L1. This refers to the local hydraulic loss in diffuser section L2. This refers to the local hydraulic loss in diffuser section L3. This refers to the local hydraulic loss in diffuser section L4. This refers to the local hydraulic loss at the inlet of the diffuser section. This refers to the local hydraulic loss at the outlet of the diffuser section.

10. The design method for side-type inlet and outlet of a pumped storage power station based on minimum hydraulic loss according to claim 1, characterized in that, The formula for the sum of the total hydraulic losses of the side-type inlet and outlet is: in, This is the sum of hydraulic losses along the entire length of the route. This is the sum of the local hydraulic losses of each part.

Images