Optimization determination method, system and equipment for parameters of guide vane sealing structure of water turbine and medium

Abstract

The invention discloses a water turbine guide vane sealing structure parameter optimization determination method, system and device and a medium, and belongs to the technical field of water turbine guide vane sealing.The method comprises the steps that guide vane end face gap measurement data and operation condition parameters are obtained; establishing a top cover finite element model to calculate axial deformation; superposing the axial deformation to the end surface gap measurement data to obtain an actual end surface gap value; dividing the guide vane into different areas according to the actual end face gap value to calculate the end face gap water leakage amount, calculating the streaming water leakage amount of the annular gap at the shaft shoulder, and accumulating to obtain the total water leakage amount; calculating the allowable water leakage according to the rated flow and judging whether the allowable water leakage meets the requirement, if not, adjusting the protruding height of the copper plate and the parameters of the rubber back cushion and then recalculating, and if yes, outputting an optimization result. According to the method, the deformation amount of the top cover is accurately obtained through finite element analysis, the end face gap is corrected, the total water leakage amount is accurately obtained through regional calculation, and an iterative optimization mechanism is established to rapidly obtain the sealing structure parameters meeting the standard.

Description

Technical Field

[0001] This invention relates to the field of turbine guide vane sealing technology, specifically to a method, system, equipment, and medium for optimizing and determining the structural parameters of turbine guide vane sealing. Background Technology

[0002] The guide vane seal of the turbine's guide vane mechanism is a key component ensuring the safe and stable operation of the unit. The guide vane seal is divided into a vertical face seal and an end face seal. The end face seal employs a detachable and replaceable sealing structure, consisting of a copper alloy sealing plate and an elastic rubber compensating backing gasket. The guide vane end face sealing plate protrudes a certain height from the flow channel surface, pressing tightly against the sealing surfaces of the top cover and bottom ring when the guide vane is closed, preventing high-pressure side water leakage to the low-pressure side. The rubber backing gasket provides elastic compensation after the copper plate seal wears, maintaining the sealing effect.

[0003] According to GB / T15468-2020 "Basic Technical Conditions for Hydropower Turbines," the leakage of cylindrical guide vanes under rated head should not exceed 0.3% of the turbine's rated flow rate. However, in actual operation, guide vane seals frequently experience excessive leakage, which can lead to creeping after unit shutdown, posing a significant safety hazard. The main causes of excessive guide vane seal leakage include: leakage at the guide vane end face and leakage around the shaft diameter at the guide vane shoulder.

[0004] Guide vane end face gap leakage refers to the leakage of high-pressure water through a gap created between the guide vane end face and the top cover bottom ring after the copper plate seal wears or the rubber back gasket fails. Guide vane shaft diameter flow gap leakage refers to the leakage caused by high-pressure water flowing around the radial and axial gaps between the guide vane shaft shoulder and the guide vane sleeve, entering the inner side from the outer side of the end face seal.

[0005] Existing guide vane seal design methods primarily rely on designers' experience to determine parameters such as the protrusion height of the copper plate seal and the hardness of the rubber backing gasket. This experience-based design method has the following problems: First, it cannot accurately predict the deformation of the top cover under water pressure. Deformation of the top cover increases the gap between the guide vane end faces, reduces the sealing clamping force, and leads to increased leakage. Second, it lacks quantitative analysis of the differences in the gaps between different guide vane end faces, making it impossible to accurately calculate the total leakage and determine whether it meets national standards. Third, when the sealing parameters do not meet the requirements, there is a lack of systematic optimization and adjustment methods; adjustments can only be made through repeated experiments, resulting in long development cycles and high costs. Summary of the Invention

[0006] In view of the above-mentioned problems, the present invention provides a method, system, equipment and medium for optimizing and determining the sealing structure parameters of a water turbine guide vane.

[0007] Therefore, the technical problem solved by this invention is: how to accurately calculate the influence of turbine top cover deformation on the guide vane end face clearance, accurately determine the guide vane leakage after considering top cover deformation, and systematically optimize the guide vane end face sealing copper plate protrusion height and rubber back gasket structure parameters so that the guide vane leakage meets the national standard requirements.

[0008] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a method for optimizing and determining the parameters of a turbine guide vane sealing structure, comprising, Acquire end face clearance measurement data and operating condition parameters of the turbine guide vanes. The end face clearance measurement data includes the upper end face clearance value and lower end face clearance value of multiple guide vanes. The operating condition parameters include the pressure difference before and after the guide vanes and the rated flow rate. A finite element model of the turbine top cover is established, water pressure is set as the boundary condition, and static calculations are performed on the finite element model to obtain the axial deformation of the top cover at the guide vane shaft hole. The axial deformation is superimposed on the end face gap measurement data to obtain the actual end face gap value after considering the deformation of the top cover. Based on the actual end face gap value, the guide vanes are divided into different regions. For each region, the end face gap leakage is calculated using fluid dynamics formulas. The leakage around the annular gap at the guide vane shoulder is also calculated. The total leakage is obtained by adding the end face gap leakage and the annular gap leakage. The allowable leakage is calculated based on the rated flow rate. It is then determined whether the total leakage is less than the allowable leakage. If the allowable leakage is not met, the protrusion height parameter of the guide vane end face sealing copper plate and the structural parameters of the rubber back gasket are adjusted, and the total leakage is recalculated. If the allowable leakage is met, the current protrusion height parameter and structural parameters are output as the optimization result.

[0009] As a preferred embodiment of the method for optimizing and determining the sealing structure parameters of a turbine guide vane according to the present invention, the step of establishing a finite element model of the turbine top cover, setting water pressure as a boundary condition, and performing static calculations on the finite element model to obtain the axial deformation of the top cover at the guide vane shaft hole includes: A three-dimensional solid model is created based on the geometric dimensions of the top cover, and a mesh is generated. Set the material property parameters of the top cover, and apply loads and constraints to the surface of the top cover; Solve the finite element equations to obtain the displacement field distribution of the top cover; The axial displacement data of the guide vane shaft hole position is extracted from the displacement field distribution, and the axial deformation is determined based on the axial displacement data.

[0010] The beneficial effects of this preferred technical solution are as follows: By establishing a three-dimensional solid model of the top cover and performing mesh generation, setting material property parameters, applying loads and constraints to the surface of the top cover, and solving the finite element equation to obtain the displacement field distribution, the axial displacement data at the guide vane shaft hole position is extracted to determine the axial deformation, thus achieving accurate calculation of the deformation of the top cover under water pressure. Under still water closure conditions, the turbine top cover will experience axial deformation at the guide vane shaft hole. This deformation, superimposed on the end face gap, leads to a reduction in sealing clamping force or even failure. Traditional designs rely on experience to estimate the deformation, resulting in large errors and unreasonable design of the copper plate protrusion height. This solution accurately obtains the top cover deformation through finite element analysis, providing a scientific basis for subsequently determining the copper plate protrusion height and avoiding sealing failure caused by inaccurate deformation estimation.

[0011] As a preferred embodiment of the method for optimizing and determining the parameters of a turbine guide vane sealing structure according to the present invention, the step of applying loads and constraints to the top cover surface includes: The pressure load value acting on the top cover is determined based on the operating conditions of the water turbine; The pressure load is applied to the pressure-bearing surface of the top cover; Displacement constraints are applied at the fixed connection positions of the top cover.

[0012] As a preferred embodiment of the method for optimizing and determining the sealing structure parameters of a turbine guide vane according to the present invention, the step of dividing multiple guide vanes into different regions based on the actual end-face clearance value, and calculating the end-face clearance leakage for each region using fluid dynamics formulas includes: Based on the actual end face clearance values ​​of multiple guide vanes, the regions are divided, and guide vanes whose actual end face clearance values ​​are within the same clearance range are grouped into the same region. Obtain the actual end face clearance value and guide vane geometry parameters for each region; The leakage rate of each region is calculated based on the actual end face gap value, the guide vane geometric parameters, and the pressure difference before and after the guide vane. The leakage volume of the end face gap is obtained by summing up the leakage volume of all areas.

[0013] The beneficial effects of this preferred technical solution are as follows: By grouping multiple guide vanes into the same region based on their actual end-face gap values ​​falling within the same gap range, the actual end-face gap value and guide vane geometric parameters of each region are obtained. Based on these parameters and the pressure difference across the guide vanes, the leakage volume of each region is calculated and accumulated, achieving accurate segmented calculation of the guide vane end-face gap leakage volume. In actual operation, the end-face gap values ​​of different guide vanes vary, and calculating the leakage volume using a uniform gap value would result in significant errors. Traditional methods estimate the total leakage volume using an average gap value, which cannot reflect the impact of differences in guide vane gaps on leakage. This solution takes into account the gap value differences through region division, calculating the leakage volume separately for regions with small and large gaps, making the total leakage volume calculation result more accurate and providing reliable data for determining whether standards are exceeded and identifying optimization directions.

[0014] As a preferred embodiment of the method for optimizing and determining the sealing structure parameters of a turbine guide vane according to the present invention, the calculation of the leakage rate around the annular gap at the guide vane shoulder includes: Obtain the radial and axial clearances of the guide vane shoulder; The geometric parameters of the annular gap are determined based on the radial fit clearance and the axial fit clearance; Based on the geometric parameters of the annular gap and the pressure difference before and after the guide vane, the leakage rate around the shoulder of a single guide vane is calculated. The leakage rate around the shoulder of a single guide vane is multiplied by the number of guide vanes to obtain the leakage rate around the annular gap.

[0015] In a preferred embodiment of the method for optimizing and determining the parameters of a turbine guide vane sealing structure as described in this invention, the step of calculating the allowable leakage based on the rated flow rate includes: Obtain leakage control standards for turbine guide vane seals; The allowable leakage is calculated based on the leakage control standard and the rated flow rate.

[0016] As a preferred embodiment of the method for optimizing and determining the sealing structure parameters of a turbine guide vane according to the present invention, the method for adjusting the protrusion height parameter of the guide vane end face sealing copper plate and the structural parameters of the rubber backing gasket includes: When the total leakage exceeds the allowable leakage, the difference between the total leakage and the allowable leakage is calculated. The amount of end face clearance that needs to be reduced is determined based on the difference. The amount of end face clearance that needs to be reduced is added to the current protrusion height parameter to obtain the adjusted protrusion height parameter; The compression of the rubber backing pad is calculated based on the cross-sectional dimensions of the top cover sealing groove and the adjusted protrusion height parameters. Determine whether the compression amount is within the elastic deformation range of the rubber material. If it exceeds the elastic deformation range, adjust the hardness parameter or cross-sectional shape parameter of the rubber backing.

[0017] This invention provides a system for optimizing and determining the sealing structure parameters of a water turbine guide vane.

[0018] To solve the above technical problems, the present invention provides the following technical solution: an optimization and determination system for the sealing structure parameters of a turbine guide vane, comprising: a data acquisition module for acquiring end face clearance measurement data and operating condition parameters of the turbine guide vane; The finite element calculation module is used to build a finite element model of the turbine top cover and calculate the axial deformation of the top cover at the guide vane shaft hole; A gap correction module is used to superimpose the axial deformation amount onto the end face gap measurement data to obtain the actual end face gap value; The leakage calculation module is used to calculate the leakage volume of the end face gap and the leakage volume of the annular gap based on the actual end face gap value, and to accumulate them to obtain the total leakage volume. The judgment and optimization module is used to determine whether the total leakage meets the allowable leakage requirements. If it does not meet the requirements, the sealing structure parameters are adjusted. If it does meet the requirements, the optimization determination result is output.

[0019] The present invention provides a computer device, including a memory and a processor. The memory stores a computer program, and the processor executes the computer program to implement the steps of the method for optimizing and determining the parameters of a water turbine guide vane sealing structure.

[0020] The present invention provides a computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the steps of the method for optimizing and determining the parameters of a turbine guide vane sealing structure.

[0021] The beneficial effects of this invention are as follows: By establishing a finite element model of the top cover, the axial deformation under water pressure is calculated and superimposed on the end face gap measurement data, accurately reflecting the influence of top cover deformation on the guide vane seal. Traditional empirical designs neglect or roughly estimate top cover deformation, leading to unreasonable design of the copper plate protrusion height. This invention provides accurate gap data for optimizing sealing parameters through finite element analysis.

[0022] By dividing multiple guide vanes into regions based on their actual end-face clearance values ​​and calculating the leakage rate for each region, while simultaneously calculating the leakage rate around the annular gap at the shaft shoulder, the total leakage rate is accurately obtained. Traditional methods that estimate using average clearance values ​​cannot reflect the differences in guide vane clearances; this invention achieves more accurate results through region-based calculations.

[0023] By establishing an iterative optimization mechanism constrained by allowable leakage, the copper plate protrusion height and rubber backing parameters are automatically adjusted when the total leakage exceeds the standard, allowing for the rapid acquisition of sealing parameters that meet national standards during the design phase and shortening the R&D cycle. Attached Figure Description

[0024] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a flowchart illustrating the overall process of determining the optimization parameters of a turbine guide vane sealing structure, as provided in one embodiment of the present invention. Detailed Implementation

[0026] To make the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of the present invention.

[0027] Example 1, referring to Figure 1 This is one embodiment of the present invention, which provides a method for optimizing and determining the parameters of a turbine guide vane sealing structure, including: Steps: Obtain the end face clearance measurement data and operating condition parameters of the turbine guide vanes. The end face clearance measurement data includes the upper end face clearance value and lower end face clearance value of multiple guide vanes. The operating condition parameters include the pressure difference before and after the guide vanes and the rated flow rate. Step 1: Establish a finite element model of the turbine top cover, set water pressure as the boundary condition, perform static calculations on the finite element model, and obtain the axial deformation of the top cover at the guide vane shaft hole; Step 2: Add the axial deformation to the end face gap measurement data to obtain the actual end face gap value after considering the deformation of the top cover; Step 3: Divide the multiple guide vanes into different regions according to the actual end face clearance value. Calculate the end face clearance leakage for each region using fluid dynamics formulas. Calculate the leakage around the annular gap at the guide vane shoulder. Add the end face clearance leakage and the annular gap leakage to obtain the total leakage. Step 4: Calculate the allowable leakage based on the rated flow rate, and determine whether the total leakage is less than the allowable leakage. If it is not satisfied, adjust the protrusion height parameter of the guide vane end face sealing copper plate and the structural parameters of the rubber back gasket, and then recalculate the total leakage. If it is satisfied, output the current protrusion height parameter and structural parameters as the optimization determination result.

[0028] Traditional turbine guide vane seal design relies primarily on designers' experience to determine the copper plate protrusion height and rubber backing parameters. This approach fails to accurately predict the impact of top cover deformation under water pressure on the end-face clearance and lacks quantitative analysis of differences in end-face clearance among different guide vanes. Consequently, the designed seal structure experiences excessive leakage during actual operation. When guide vane leakage exceeds national standard limits, it can cause creeping after unit shutdown, posing a significant safety hazard. Existing design methods lack a systematic optimization mechanism, relying solely on physical testing after prototype manufacturing to verify performance. If requirements are not met, redesign and manufacturing are necessary, resulting in long development cycles and high costs.

[0029] This embodiment accurately calculates the axial deformation under water pressure by establishing a finite element model of the top cover. The deformation is then superimposed onto the end-face gap measurement data to obtain the actual end-face gap value. Based on the actual end-face gap value, the leakage rate of the end-face gap is calculated by region, and the leakage rate around the annular gap at the shaft shoulder is also calculated. An iterative optimization mechanism with allowable leakage rate as a constraint is established, enabling rapid acquisition of sealing structure parameters that meet national standards during the design phase. This method solves the problems of traditional designs neglecting top cover deformation, inaccurate leakage rate calculations, and lack of systematic optimization. It achieves scientific determination and automated optimization of guide vane sealing structure parameters, shortening the R&D cycle and reducing prototype manufacturing costs.

[0030] Example 2, an embodiment of the present invention, provides a method for optimizing and determining the parameters of a turbine guide vane sealing structure based on the previous embodiment, including: Step 1: Establish a finite element model of the turbine top cover, set water pressure as the boundary condition, perform static calculations on the finite element model, and obtain the axial deformation of the top cover at the guide vane shaft hole, including the following steps A1-A4: A1: Create a 3D solid model based on the geometric dimensions of the top cover and perform mesh generation; A2: Set the material property parameters of the top cover, and apply loads and constraints to the surface of the top cover; A3: Solve the finite element equations to obtain the displacement field distribution of the top cover; A4: Extract axial displacement data of the guide vane shaft hole position from the displacement field distribution, and determine the axial deformation based on the axial displacement data.

[0031] In this embodiment of the application, in step A1, the establishment of a three-dimensional solid model and the meshing are carried out by: obtaining geometric parameters such as the outer diameter, inner diameter, thickness, guide vane shaft hole diameter, number and distribution of guide vane shaft holes, etc. of the top cover according to the design drawings of the top cover; establishing a solid geometric model of the top cover in three-dimensional modeling software; using tetrahedral mesh or hexahedral mesh when meshing the three-dimensional solid model; and refining the mesh in the area around the guide vane shaft hole to accurately capture the stress and deformation distribution at that location; the total number of mesh elements is determined according to the calculation accuracy requirements and calculation resources.

[0032] In an optional implementation, in step A1, the establishment of a three-dimensional solid model and the meshing can be achieved by: establishing a three-dimensional model of the roof using parametric modeling, setting the key geometric dimensions of the roof as adjustable parameters, automatically updating the model by modifying the parameter values ​​when the roof structure dimensions change, and using adaptive meshing technology for meshing, automatically refining the mesh in areas with large stress gradients and using a coarser mesh in areas with gentle stress, thereby reducing the number of meshes to improve computational efficiency while ensuring computational accuracy.

[0033] In another optional implementation, in step A1, the establishment of the three-dimensional solid model and the meshing can also be achieved by: simplifying the top cover structure, ignoring minor features that have little impact on deformation calculation, such as bolt holes and small fillets, and retaining only the main structural features that affect the overall stiffness and deformation. The simplified model has fewer meshes and higher computational efficiency. The computational accuracy of the simplified model is verified to meet the engineering requirements by comparing it with the complete model.

[0034] In this embodiment of the application, in step A2, the load and constraint conditions applied to the top cover surface are achieved by: setting material property parameters such as the elastic modulus, Poisson's ratio and density of the top cover material; determining the water pressure value acting on the water side surface of the top cover according to the rated head of the turbine and the static water shutdown condition; applying the water pressure as a uniformly distributed load to the pressure surface of the top cover; and applying fixed or elastic constraints at the connection position between the top cover and the frame or volute to constrain the axial and radial displacement at that position.

[0035] In an optional implementation, in step A2, applying loads and constraints to the top cover surface can be achieved by: considering the property changes of the top cover material at different temperatures, setting the elastic modulus and Poisson's ratio at the corresponding temperature according to the actual operating temperature of the turbine, considering the combined effect of hydrostatic pressure and hydrodynamic pressure when applying water pressure loads, superimposing the dynamic pressure generated by water flow impact on the hydrostatic pressure, and setting the constraints according to the actual installation method of the top cover. If the top cover is connected by flange bolts, constraints are applied at the bolt hole positions.

[0036] In another optional implementation, in step A2, applying loads and constraints to the top cover surface can also be achieved by: using an anisotropic material model, setting material parameters for the differences in mechanical properties of cast or forged top covers in different directions, using a segmented loading method for water pressure loads, simulating the loading process from zero pressure to the pressure corresponding to the rated water head, and obtaining the deformation evolution law of the top cover during the loading process through nonlinear analysis.

[0037] It should be noted that the axial displacement data of the guide vane shaft hole position is extracted from the displacement field distribution by: locating the edge nodes of all guide vane shaft holes in the finite element analysis results, extracting the axial displacement component of each guide vane shaft hole edge node, averaging the axial displacement values ​​of all edge nodes of a single guide vane shaft hole to obtain the average axial deformation of that guide vane shaft hole, performing statistical analysis on the average axial deformation of all guide vane shaft holes, and selecting the maximum or average value as the axial deformation of the top cover at the guide vane shaft hole.

[0038] Furthermore, when determining the axial deformation based on axial displacement data, the non-uniformity of the top cover deformation is considered. Due to differences in stress state and structural stiffness, the axial deformation of the guide vane shaft holes at different locations varies. For guide vane shaft holes located in the central region of the top cover, the axial deformation is relatively small due to the strong support of the surrounding structure. For guide vane shaft holes located in the edge region of the top cover, the axial deformation is relatively large. When subsequently superimposing the deformation amount onto the end face clearance, the axial deformation amount corresponding to the guide vane at different locations is used to make the clearance correction more accurate.

[0039] It should be noted that the loads and constraints applied to the top surface include: The pressure load value acting on the top cover is determined based on the operating conditions of the turbine. Apply a pressure load to the pressure-bearing surface of the top cover; Apply displacement constraints at the fixed connection points of the top cover.

[0040] It should be noted that the axial deformation is superimposed on the end face clearance measurement data by: for each guide vane, adding the axial deformation of the top cover corresponding to the guide vane position to the upper end face clearance measurement value of the guide vane to obtain the actual upper end face clearance value of the guide vane after considering the deformation of the top cover; the same method is used to process the lower end face clearance to obtain the actual lower end face clearance value of the guide vane; and the sum of the upper end face clearance value and the lower end face clearance value is obtained to obtain the total actual end face clearance value of the guide vane.

[0041] Furthermore, the consistency between the deformation direction of the top cover and the clearance direction of the end face is considered during the superposition process. The top cover deforms upward under water pressure, and the axial deformation is positive. This deformation increases the clearance between the top cover and the upper end face of the guide vane. Therefore, the axial deformation is directly added to the measured value of the clearance of the upper end face. For the lower end face, the bottom ring deforms downward under water pressure. If the deformation of the bottom ring also needs to be considered, a similar method is used.

[0042] Step 3: Divide the multiple guide vanes into different regions based on the actual end face clearance value. Calculate the end face clearance leakage for each region using fluid dynamics formulas, and calculate the leakage around the annular gap at the guide vane shoulder. Summate the end face clearance leakage and the annular gap leakage to obtain the total leakage, including the following steps B1-B8: B1: Divide the region according to the actual end face clearance values ​​of multiple guide vanes, and group guide vanes whose actual end face clearance values ​​are within the same clearance range into the same region; B2: Obtain the actual end face clearance value and guide vane geometry parameters for each region; B3: Calculate the leakage volume of each area based on the actual end face gap value, guide vane geometric parameters, and pressure difference before and after the guide vane; B4: The leakage amount of the end face gap is obtained by summing up the leakage amounts of all areas.

[0043] B5: Obtain the radial and axial clearances of the guide vane shoulder; B6: Determine the geometric parameters of the annular gap based on the radial and axial fit clearances; B7: Calculate the leakage around the shoulder of a single guide vane based on the geometric parameters of the annular gap and the pressure difference before and after the guide vane; B8: Multiply the leakage rate around the shoulder of a single guide vane by the number of guide vanes to obtain the leakage rate around the annular gap.

[0044] In this embodiment of the application, in step 3, the guide vanes are divided into different regions according to the actual end face gap values ​​by: sorting the actual end face gap values ​​of all guide vanes from smallest to largest, setting a gap segmentation threshold, and dividing the guide vanes into several gap regions according to the distribution characteristics of the gap values. Guide vanes with gaps smaller than the first threshold are assigned to the first region, guide vanes with gap values ​​between the first and second thresholds are assigned to the second region, and guide vanes with gap values ​​greater than the second threshold are assigned to the third region. The segmentation threshold is determined based on the statistical distribution of the gap values ​​and the required calculation accuracy.

[0045] In an optional implementation, in step 3, dividing multiple guide vanes into different regions based on the actual end-face gap values ​​can be achieved by: automatically grouping the actual end-face gap values ​​of the guide vanes using a clustering analysis method, clustering the guide vanes into several groups based on the similarity of the gap values, with each group serving as a region, and adaptively determining the number of clusters based on the dispersion of the gap values. When the dispersion of the gap values ​​is high, the number of clusters is increased to improve calculation accuracy, and when the gap values ​​are relatively concentrated, the number of clusters is reduced to improve calculation efficiency.

[0046] In another optional implementation, in step 3, dividing the multiple guide vanes into different regions based on the actual end face gap value can also be achieved by: setting a fixed gap interval step size, dividing the gap value range into multiple equally spaced intervals according to the fixed step size, with each interval corresponding to a region. The selection of the gap interval step size takes into account both the gap measurement accuracy and the leakage calculation accuracy. If the gap interval step size is too large, the calculation accuracy will be reduced, and if the gap interval step size is too small, the calculation complexity will be increased.

[0047] In this embodiment of the application, in step 3, the leakage of the end face gap is calculated for each region using a fluid dynamics formula: the leakage of the end face gap is calculated using a parallel plate gap flow formula. For a single region, the leakage is proportional to the cube of the representative gap value of that region, proportional to the square root of the pressure difference before and after the guide vane, and proportional to the product of the circumferential length of the guide vane end face and the number of guide vanes in that region. The leakage of that region is calculated by substituting the above parameters into the fluid dynamics formula.

[0048] In an optional implementation, in step 3, the leakage of the end face gap for each region can be calculated using fluid dynamics formulas by: using an annular gap flow formula to calculate the leakage of the end face gap, considering the geometric characteristics of the annular distribution of the sealing area of ​​the guide vane end face, determining the geometric parameters of the flow channel based on the inner diameter, outer diameter and gap height of the annulus, and combining the pressure difference before and after the guide vane and the fluid viscosity, and using an annular gap flow calculation formula to obtain the leakage of that region.

[0049] In another optional implementation, in step 3, the calculation of the leakage volume of the end face gap using fluid dynamics formulas for each region can also be achieved by: considering the actual flow state of the water in the end face gap, determining whether the flow is laminar or turbulent based on the Reynolds number, using the Poiseuille flow formula to calculate the leakage volume for laminar flow, and introducing a turbulence correction coefficient for turbulent flow. The correction coefficient is determined based on the Reynolds number and the gap geometry parameters. A more accurate leakage volume can be obtained by calculating the leakage volume using the corrected formula.

[0050] Step 4: Calculate the allowable leakage based on the rated flow rate, and determine whether the total leakage is less than the allowable leakage. If not, adjust the protrusion height parameter of the guide vane end face sealing copper plate and the structural parameters of the rubber back gasket, and then recalculate the total leakage. If the allowable leakage is met, output the current protrusion height parameter and structural parameters as the optimization determination result, including the following steps C1-C7: C1: Obtain the leakage control standard for the turbine guide vane seal; C2: Calculate the allowable leakage based on the leakage control standard and rated flow rate.

[0051] C3: When the total leakage exceeds the allowable leakage, calculate the difference between the total leakage and the allowable leakage. C4: Determine the amount of end face clearance that needs to be reduced based on the difference; C5: Add the amount of end face clearance that needs to be reduced to the current protrusion height parameter to obtain the adjusted protrusion height parameter; C6: Calculate the compression of the rubber backing gasket based on the cross-sectional dimensions of the top cover sealing groove and the adjusted protrusion height parameters; C7: Determine whether the compression amount is within the elastic deformation range of the rubber material. If it exceeds the elastic deformation range, adjust the hardness parameter or cross-sectional shape parameter of the rubber backing.

[0052] It should be noted that the actual end face clearance value of each region is obtained by: statistically processing the actual end face clearance values ​​of all guide vanes belonging to the same region, calculating the average clearance value, maximum clearance value, or weighted average clearance value of the region, which serves as the representative clearance value of the region for subsequent leakage calculation. When there are many guide vanes in the region and the clearance values ​​are evenly distributed, the average clearance value is used. When there are individual guide vanes in the region with significantly larger clearance values, the weighted average clearance value is used, assigning higher weights to guide vanes with larger clearance values.

[0053] Furthermore, the guide vane geometric parameters include the circumferential length of the guide vane end face, the guide vane height, and the number of guide vanes. The circumferential length of the guide vane end face is the circumferential arc length of the guide vane end face in contact with the top cover or bottom ring; the guide vane height is the length of the guide vane in the axial direction; and the number of guide vanes is the number of guide vanes contained in this area. These geometric parameters, together with the end face clearance value, determine the geometric characteristics of the end face leakage channel and are necessary parameters for calculating the leakage rate.

[0054] It should be noted that the pressure difference across the guide vane is determined based on the turbine's operating conditions. Under static water shut-off conditions, the pressure on the front side of the guide vane is the high-pressure side, equal to the static pressure corresponding to the head, while the pressure on the rear side is the low-pressure side, close to the tailrace pressure. The pressure difference across the guide vane is the difference between the two pressures. The pressure difference across the guide vane varies under different head conditions, and the pressure difference across the guide vane corresponding to the rated head is used when calculating leakage.

[0055] Furthermore, the calculation of the pressure difference before and after the guide vane takes into account head loss. There are friction losses and local losses as the water flows from the upstream water level to the front of the guide vane through the water intake system and the volute. The actual pressure at the front of the guide vane is less than the static pressure corresponding to the upstream water level. The head loss is determined using hydraulic calculation methods, and the pressure at the front of the guide vane is obtained by subtracting the head loss from the upstream head. The pressure difference before and after the guide vane is then calculated by combining this with the tailrace pressure.

[0056] It should be noted that the geometric parameters for determining the annular gap based on the radial and axial fit clearances include: determining the radial fit clearance based on the outer diameter of the guide vane shoulder and the inner diameter of the guide vane sleeve, where the clearance is the annular gap height in the radial direction; and determining the axial fit clearance based on the distance between the end face of the guide vane shoulder and the end face of the middle sleeve, where the clearance is the plate gap height in the axial direction. The geometric parameters of the annular gap include the inner diameter, outer diameter, radial height, and axial length of the annular gap.

[0057] Furthermore, the flow path of the annular gap is that high-pressure water enters the axial gap from the outer side of the guide vane end face seal along the radial gap, and then flows to the inner side of the end face seal along the radial gap. The calculation of the leakage around the gap needs to consider the resistance characteristics of the series flow of the radial and axial gaps. The series gap flow formula is adopted to superimpose the radial gap resistance and the axial gap resistance, and the leakage around the gap is calculated based on the total resistance and the pressure difference before and after the guide vane.

[0058] It should be noted that the allowable leakage rate is calculated based on the leakage control standard and rated flow rate by obtaining the leakage control requirements for guide vane seals specified in the national standard GB / T15468-2020 "Basic Technical Conditions for Water Turbines". This standard stipulates that the leakage rate of cylindrical guide vanes under rated head should not exceed 0.3% of the rated flow rate of the water turbine. The allowable leakage rate is obtained by multiplying the rated flow rate by 0.3%. When the calculated total leakage rate exceeds the allowable leakage rate, it is determined that the sealing structure parameters do not meet the requirements and need to be optimized and adjusted.

[0059] Furthermore, a safety margin is set when determining whether the total leakage is less than the allowable leakage. Considering that the guide vane seal will wear down during long-term operation, leading to increased leakage, a safety factor is introduced into the judgment standard, requiring the total leakage to be less than 80% to 90% of the allowable leakage. This provides a margin for seal wear and ensures that the leakage always meets national standard requirements throughout the seal's service life.

[0060] It should be noted that the amount of end face gap that needs to be reduced is determined based on the difference by: establishing a mathematical model of leakage and gap value based on the relationship that the leakage amount of the end face gap is proportional to the cube of the gap value; the difference between the current total leakage amount and the allowable leakage amount is the leakage amount that needs to be reduced; and then using an iterative calculation method to solve the problem by back-calculating the amount of gap that needs to be reduced based on this leakage difference. Initially, a gap reduction amount is assumed, and the corresponding leakage reduction amount is calculated. If the requirement is not met, the gap reduction amount is adjusted, and the calculation is repeated until the leakage reduction amount equals the difference.

[0061] Furthermore, when determining the amount of end face clearance that needs to be reduced, priority should be given to reducing the clearance in areas with larger clearance values. For multiple clearance areas, areas with larger clearance values ​​contribute more to the total leakage. Prioritizing the reduction of clearance in these areas can more effectively reduce the total leakage. In practice, different clearance reduction amounts can be assigned to different areas, with larger reduction amounts allocated to areas with larger clearances and smaller reduction amounts allocated to areas with smaller clearances.

[0062] It should be noted that the compression of the rubber backing gasket is calculated based on the cross-sectional dimensions of the top cover sealing groove and the adjusted protrusion height parameter by: obtaining the depth dimension of the top cover sealing groove and the free height of the rubber backing gasket; the height of the copper plate seal protruding from the top cover surface after installation is the protrusion height parameter; when the guide vane is closed, the copper plate seal is pressed into the sealing groove, and the pressing depth is equal to the protrusion height parameter; the compression of the rubber backing gasket is equal to the pressing depth minus the remaining space of the sealing groove; the remaining space of the sealing groove is the sealing groove depth minus the sum of the copper plate seal thickness and the free height of the rubber backing gasket.

[0063] Furthermore, determining whether the compression amount is within the elastic deformation range of the rubber material is based on the compression set of the rubber material. The elastic deformation range of rubber materials is typically 20% to 40% of their free height. When the compression amount exceeds this range, the rubber will undergo permanent plastic deformation and cannot fully rebound, resulting in a decrease in sealing performance. The ratio of the calculated compression amount to the free height of the rubber backing is used as the compression ratio. When the compression ratio exceeds 40%, it is determined that the elastic deformation range is exceeded, and the rubber hardness or cross-sectional shape needs to be adjusted.

[0064] Specifically, adjusting the hardness parameters of the rubber backing pad includes selecting a rubber material with lower hardness.

[0065] Rubber hardness is usually expressed in Shore hardness. The lower the hardness, the softer the rubber and the stronger its elastic deformation ability. When the compression is too large, rubber with lower hardness should be selected. The preferred hardness range is 70 to 85 Shore. By reducing the hardness, the compressibility of the rubber is increased, so that it can still maintain elastic deformation under large compression and avoid permanent deformation.

[0066] Specifically, adjusting the cross-sectional shape parameters includes increasing the deformation compensation space of the rubber backing.

[0067] The cross-sectional shape of the rubber backing pad can be rectangular, trapezoidal, or grooved. The grooved structure has one or more grooves on the rubber backing pad. The grooves provide space for the rubber to compress and deform. When the rubber is compressed, the grooves close to absorb the deformation. By increasing the depth or number of grooves, the deformation compensation space is increased, so that the rubber can still maintain its elasticity under a large amount of compression.

[0068] It should be noted that the total leakage was recalculated using an iterative optimization method after adjusting the structural parameters.

[0069] After each adjustment of the copper plate protrusion height parameter and the rubber back pad structure parameter, the actual end face gap value is updated, and the calculation of the end face gap leakage and the annular gap flow leakage is re-executed. The new total leakage is accumulated, and it is determined whether the new total leakage is less than the allowable leakage. If it is still not satisfied, the parameters are adjusted again, and the iteration process is repeated until the total leakage is less than the allowable leakage or the maximum number of iterations is reached.

[0070] Furthermore, during the iterative optimization process, the parameter values ​​and leakage values ​​for each iteration are recorded.

[0071] Establish a database of the correspondence between parameters and leakage volume. By analyzing historical iteration data, use gradient descent or Newton's method to determine the direction and magnitude of parameter adjustment for the next iteration, thereby accelerating the convergence speed and reducing the number of iterations. When the change in leakage volume between two consecutive iterations is less than a set threshold, it is determined that convergence has been achieved, and the iteration is stopped and the current parameters are output.

[0072] Example 3 is an embodiment of the present invention. This embodiment provides an optimization and determination system for the sealing structure parameters of a turbine guide vane, including: a data acquisition module for acquiring end face clearance measurement data and operating condition parameters of the turbine guide vane; The finite element calculation module is used to build a finite element model of the turbine top cover and calculate the axial deformation of the top cover at the guide vane shaft hole; A gap correction module is used to superimpose the axial deformation amount onto the end face gap measurement data to obtain the actual end face gap value; The leakage calculation module is used to calculate the leakage volume of the end face gap and the leakage volume of the annular gap based on the actual end face gap value, and to accumulate them to obtain the total leakage volume. The judgment and optimization module is used to determine whether the total leakage meets the allowable leakage requirements. If it does not meet the requirements, the sealing structure parameters are adjusted. If it does meet the requirements, the optimization determination result is output.

[0073] This embodiment also provides an electronic device applicable to a method for optimizing and determining the parameters of a turbine guide vane sealing structure, comprising: a memory and a processor; the memory is used to store computer-executable instructions, and the processor is used to execute the computer-executable instructions to implement the method for optimizing and determining the parameters of a turbine guide vane sealing structure as proposed in the above embodiment.

[0074] This embodiment also provides a storage medium storing a computer program that, when executed by a processor, implements a method for optimizing and determining the parameters of a turbine guide vane sealing structure as proposed in the above embodiment.

[0075] The storage medium proposed in this embodiment and the method for optimizing and determining the parameters of a turbine guide vane sealing structure proposed in the above embodiments belong to the same inventive concept. Technical details not described in detail in this embodiment can be found in the above embodiments, and this embodiment has the same beneficial effects as the above embodiments.

[0076] Based on the above description of the implementation methods, those skilled in the art can clearly understand that the present invention can be implemented using software and necessary general-purpose hardware, and of course, it can also be implemented using hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as a computer floppy disk, read-only memory (ROM), random access memory (RAM), flash memory, hard disk, or optical disk, etc., including several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods of the various embodiments of the present invention.

[0077] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to preferred embodiments, 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 spirit and 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 method for optimizing and determining the parameters of a turbine guide vane sealing structure, characterized in that: include, Acquire end face clearance measurement data and operating condition parameters of the turbine guide vanes. The end face clearance measurement data includes the upper end face clearance value and lower end face clearance value of multiple guide vanes. The operating condition parameters include the pressure difference before and after the guide vanes and the rated flow rate. A finite element model of the turbine top cover is established, water pressure is set as the boundary condition, and static calculations are performed on the finite element model to obtain the axial deformation of the top cover at the guide vane shaft hole. The axial deformation is superimposed on the end face gap measurement data to obtain the actual end face gap value after considering the deformation of the top cover. Based on the actual end face gap value, the guide vanes are divided into different regions. For each region, the end face gap leakage is calculated using fluid dynamics formulas. The leakage around the annular gap at the guide vane shoulder is also calculated. The total leakage is obtained by adding the end face gap leakage and the annular gap leakage. The allowable leakage is calculated based on the rated flow rate. It is then determined whether the total leakage is less than the allowable leakage. If the allowable leakage is not met, the protrusion height parameter of the guide vane end face sealing copper plate and the structural parameters of the rubber back gasket are adjusted, and the total leakage is recalculated. If the allowable leakage is met, the current protrusion height parameter and structural parameters are output as the optimization result.

2. The method for optimizing and determining the parameters of a turbine guide vane sealing structure as described in claim 1, characterized in that: The establishment of a finite element model of the turbine top cover, with water pressure as the boundary condition, and the static calculation of the finite element model to obtain the axial deformation of the top cover at the guide vane shaft hole includes: A three-dimensional solid model is created based on the geometric dimensions of the top cover, and a mesh is generated. Set the material property parameters of the top cover, and apply loads and constraints to the surface of the top cover; Solve the finite element equations to obtain the displacement field distribution of the top cover; The axial displacement data of the guide vane shaft hole position is extracted from the displacement field distribution, and the axial deformation is determined based on the axial displacement data.

3. The method for optimizing and determining the parameters of a turbine guide vane sealing structure as described in claim 2, characterized in that: The load and constraint conditions applied to the surface of the top cover include: The pressure load value acting on the top cover is determined based on the operating conditions of the water turbine; The pressure load is applied to the pressure-bearing surface of the top cover; Displacement constraints are applied at the fixed connection positions of the top cover.

4. The method for optimizing and determining the parameters of a turbine guide vane sealing structure as described in claim 3, characterized in that: The step of dividing multiple guide vanes into different regions based on the actual end-face clearance value, and calculating the end-face clearance leakage for each region using fluid dynamics formulas, includes: Based on the actual end face clearance values ​​of multiple guide vanes, the regions are divided, and guide vanes whose actual end face clearance values ​​are within the same clearance range are grouped into the same region. Obtain the actual end face clearance value and guide vane geometry parameters for each region; The leakage rate of each region is calculated based on the actual end face gap value, the guide vane geometric parameters, and the pressure difference before and after the guide vane. The leakage volume of the end face gap is obtained by summing up the leakage volume of all areas.

5. The method for optimizing and determining the parameters of a turbine guide vane sealing structure as described in claim 4, characterized in that: The calculation of the leakage rate around the annular gap at the guide vane shoulder includes: Obtain the radial and axial clearances of the guide vane shoulder; The geometric parameters of the annular gap are determined based on the radial fit clearance and the axial fit clearance; Based on the geometric parameters of the annular gap and the pressure difference before and after the guide vane, the leakage rate around the shoulder of a single guide vane is calculated. The leakage rate around the shoulder of a single guide vane is multiplied by the number of guide vanes to obtain the leakage rate around the annular gap.

6. The method for optimizing and determining the parameters of a turbine guide vane sealing structure as described in claim 5, characterized in that: The calculation of the allowable leakage based on the rated flow rate includes: Obtain leakage control standards for turbine guide vane seals; The allowable leakage is calculated based on the leakage control standard and the rated flow rate.

7. The method for optimizing and determining the parameters of a turbine guide vane sealing structure as described in claim 6, characterized in that: The parameters for adjusting the protrusion height of the guide vane end face sealing copper plate and the structural parameters of the rubber backing include: When the total leakage exceeds the allowable leakage, the difference between the total leakage and the allowable leakage is calculated. The amount of end face clearance that needs to be reduced is determined based on the difference. The amount of end face clearance that needs to be reduced is added to the current protrusion height parameter to obtain the adjusted protrusion height parameter; The compression of the rubber backing pad is calculated based on the cross-sectional dimensions of the top cover sealing groove and the adjusted protrusion height parameters. Determine whether the compression amount is within the elastic deformation range of the rubber material. If it exceeds the elastic deformation range, adjust the hardness parameter or cross-sectional shape parameter of the rubber backing.

8. A system for optimizing and determining the parameters of a turbine guide vane sealing structure, using the method for optimizing and determining the parameters of a turbine guide vane sealing structure as described in any one of claims 1 to 7, characterized in that, include: The data acquisition module is used to acquire measurement data of the end face clearance of the turbine guide vanes and operating condition parameters; The finite element calculation module is used to build a finite element model of the turbine top cover and calculate the axial deformation of the top cover at the guide vane shaft hole; A gap correction module is used to superimpose the axial deformation amount onto the end face gap measurement data to obtain the actual end face gap value; The leakage calculation module is used to calculate the leakage volume of the end face gap and the leakage volume of the annular gap based on the actual end face gap value, and to accumulate them to obtain the total leakage volume. The judgment and optimization module is used to determine whether the total leakage meets the allowable leakage requirements. If it does not meet the requirements, the sealing structure parameters are adjusted. If it does meet the requirements, the optimization determination result is output.

9. A computer device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that, When the processor executes the computer program, it implements the steps of the method for optimizing and determining the parameters of the turbine guide vane sealing structure according to any one of claims 1 to 7.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the steps of the method for optimizing and determining the parameters of the guide vane sealing structure of a water turbine, as described in any one of claims 1 to 7.

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