Compressor blade tip treatment method for inhibiting blade tip separation loss

Abstract

The invention relates to the technical field of turbomachinery, in particular to a gas compressor blade tip treatment method for inhibiting blade tip separation loss, which comprises the following steps of: creating a detailed computational domain and a grid containing a blade tip clearance area for a gas turbine gas compressor rotor with a specified clearance height; reasonable boundary conditions are set through a computational fluid mechanics solver; performing numerical simulation on the calculation model through a turbulence model of turbulence scale analysis according to boundary conditions; the numerical simulation result is analyzed, and a flow field axial speed distribution cloud picture of the section of each axial position of the blade top is obtained; the height of blade top separation flow is obtained from the axial speed distribution cloud picture, and the radius of a transition fillet from the blade body to the blade top is designed according to the maximum height value of blade top separation flow; and smooth transition treatment is carried out on the blade body and the blade top through the designed transition fillet radius. The method has the beneficial effects that through accurate numerical simulation and blade tip geometric optimization, blade tip leakage and separation flow of the gas turbine compressor are effectively controlled.

Description

Technical Field

[0001] The invention relates to the technical field of impeller machinery, and in particular to a compressor blade tip processing method for suppressing blade tip separation loss. Background Art

[0002] The flow process in the gap area of ​​the gas turbine compressor is very complex, and the loss caused by the gap flow accounts for a large proportion of the total energy loss of the moving blades and the compressor stage. The compressor performance is highly sensitive to the tip clearance, and the increase in the clearance during operation usually leads to the decline of compressor performance. In actual service, the tip clearance may increase temporarily or permanently, thus affecting the economy and stability of gas turbine operation.

[0003] Due to the pressure difference between the pressure surface and the suction surface of the compressor moving blade tip area, the flow near the blade tip will cross from the pressure surface to the suction surface, forming a blade tip leakage flow. For gas turbines, the compressor blades are large in size. When the flow near the blade tip crosses from the blade body to the gap area, local separation flow may occur, causing additional losses, worsening the blade tip flow, and reducing the compressor efficiency. Based on the local flow characteristics at the blade top, reasonable processing of the blade top geometry can effectively improve the local flow at the blade tip and enhance the compressor performance. Summary of the invention

[0004] In view of the above problems or problems existing in the prior art, the present invention is proposed.

[0005] Therefore, the object of the present invention is to provide a compressor blade tip processing method for suppressing blade tip separation loss, which can solve the problem of blade tip leakage and separation flow caused by the flow complexity in the blade tip gap area of ​​the current gas turbine compressor, which will reduce the compressor efficiency and increase energy loss.

[0006] To solve the above technical problems, the present invention provides the following technical solutions: a compressor blade tip processing method for suppressing blade tip separation loss, comprising creating a detailed calculation domain and a mesh including a blade tip clearance region for a gas turbine compressor rotor with a specified clearance height;

[0007] Set reasonable boundary conditions through computational fluid dynamics solver;

[0008] According to the boundary conditions, the computational model is numerically simulated by a turbulence model that resolves the turbulence scale;

[0009] Analyze the numerical simulation results to obtain the axial velocity distribution cloud diagram of the flow field at each axial position of the blade tip;

[0010] The height of the blade tip separation flow is obtained from the axial velocity distribution cloud map, and the transition fillet radius from the blade body to the blade tip is designed according to the maximum height value of the blade tip separation flow;

[0011] By means of the designed transition fillet radius, a smooth transition is carried out between the blade body and the blade tip.

[0012] As a preferred embodiment of the compressor blade tip treatment method for suppressing blade tip separation loss of the present invention, wherein: the computational domain refers to the need to construct an accurate computational domain for simulating the blade tip clearance region of the compressor rotor of a gas turbine, which includes the blade tip clearance.

[0013] As a preferred embodiment of the compressor blade tip treatment method for suppressing blade tip separation loss of the present invention, wherein: the mesh includes creating a computational mesh within the computational domain, and the mesh region includes the blade surface and the blade tip region.

[0014] As a preferred embodiment of the compressor blade tip treatment method for suppressing blade tip separation loss of the present invention, wherein: the boundary conditions are the solid wall conditions and the inlet and outlet conditions, and these conditions simulate the environment during the actual operation of the compressor.

[0015] As a preferred embodiment of the compressor blade tip treatment method for suppressing blade tip separation loss of the present invention, wherein: the solid wall includes the hub, the casing, and the blade surface; the inlet and outlet conditions include the total temperature, the total pressure, and the flow angle.

[0016] As a preferred embodiment of the compressor blade tip treatment method for suppressing blade tip separation loss of the present invention, wherein: the numerical simulation is carried out using a CFD solver, and the turbulence models adopted are SBES and DES that can resolve the turbulence scale.

[0017] As a preferred embodiment of the compressor blade tip treatment method for suppressing blade tip separation loss of the present invention, wherein: the maximum height value of the blade tip separation flow is determined by analyzing the data within the entire axial range in the axial velocity distribution contour map to determine the maximum value of the separation flow height.

[0018] As a preferred embodiment of the compressor blade tip treatment method for suppressing blade tip separation loss of the present invention, wherein: the smooth transition treatment is used to suppress the separation flow caused by blade tip leakage.

[0019] To solve the above technical problems, the present invention provides the following technical solution: A computer device, comprising a memory and a processor, the memory stores a computer program, and is characterized in that when the processor executes the computer program, the steps of the method according to any one of claims 1 to 8 are implemented.

[0020] To solve the above technical problems, the present invention provides the following technical solution: A computer-readable storage medium, on which a computer program is stored, and is characterized in that when the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 8 are implemented.

[0021] Advantages of the present invention: Through precise numerical simulation and tip geometry optimization, the present invention effectively controls the tip leakage and separation flow of the gas turbine compressor. The use of a transition fillet design significantly reduces the height and width of the tip separation, reduces leakage losses, and improves the compressor efficiency. In addition, this method does not require additional physical modifications or complex operations, is easy to implement, is environmentally friendly, does not use chemical agents, and has low maintenance costs, showing significant economic and environmental benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] To more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings. Among them:

[0023] Figure 1 Schematic diagram of tip leakage flow and tip separation flow of the compressor tip treatment method for suppressing tip separation loss.

[0024] Figure 2 Schematic diagram of the conventional blade tip numerical simulation grid of the compressor tip treatment method for suppressing tip separation loss.

[0025] Figure 3 Schematic diagram of the axial velocity distribution of the conventional blade tip numerical simulation results of the compressor tip treatment method for suppressing tip separation loss.

[0026] Figure 4 Schematic diagram of the change of the tip separation flow height with the axial chord length position of the compressor tip treatment method for suppressing tip separation loss.

[0027] Figure 5 Schematic diagram of the chordwise cross-section of the blade of the compressor tip treatment method for suppressing tip separation loss.

[0028] Figure 6 Schematic diagram of the axial velocity distribution of the numerical simulation results after the compressor tip of the compressor tip treatment method for suppressing tip separation loss is rounded. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0029] To make the above objects, features, and advantages of the present invention more obvious and understandable, the following will provide a detailed description of the specific embodiments of the present invention in conjunction with the drawings in the specification.

[0030] In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. However, the present invention may be practiced in other ways than those specifically described herein, and those skilled in the art can make similar extensions without departing from the spirit of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed below.

[0031] Secondly, as used herein, an "embodiment" or "embodiments" refer to specific features, structures, or characteristics that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it an individual or alternative embodiment that is mutually exclusive with other embodiments.

[0032] Embodiment 1

[0033] Referring to Figures 1 to 6 , which is an embodiment of the present invention, this embodiment provides a compressor tip treatment method for suppressing tip separation loss, which can solve the problems that the tip leakage and separation flow problems caused by the flow complexity in the tip clearance region of the current gas turbine compressor reduce the compressor efficiency and increase the energy loss.

[0034] Specifically, for a gas turbine compressor rotor with a specified clearance height, a detailed computational domain and mesh including the tip clearance region are created;

[0035] Reasonable boundary conditions are set through a computational fluid dynamics solver;

[0036] According to the boundary conditions, the computational model is numerically simulated using a turbulence model based on the resolution of the turbulence scale;

[0037] The numerical simulation results are analyzed to obtain the axial velocity distribution contour map of the flow field at the cross-section at each axial position of the tip;

[0038] The height of the tip separation flow is obtained from the axial velocity distribution contour map, and based on the maximum height value of the tip separation flow, the transition fillet radius from the blade body to the tip is designed;

[0039] The blade body and the tip are smoothly transitioned through the designed transition fillet radius.

[0040] Furthermore, the computational domain refers to an accurate computational domain that needs to be constructed to simulate the tip clearance region of the gas turbine compressor rotor, which includes the tip clearance.

[0041] Furthermore, the mesh includes creating a computational mesh within the computational domain, and the mesh region includes the blade surface and the tip region.

[0042] It should be noted that in order to capture the flow details, it is necessary to ensure that the mesh scale of the blade surface and the tip region is small enough, that is, reaching 1×10 -6m magnitude, such as Figure 2 as shown

[0043] Furthermore, the boundary conditions include solid wall conditions and inlet and outlet conditions, which simulate the environment during the actual operation of the compressor.

[0044] Furthermore, the solid wall includes the hub, the casing, and the blade surface; the inlet and outlet conditions include the total temperature, the total pressure, and the flow angle.

[0045] Furthermore, numerical simulation is carried out using a CFD solver, and the turbulence models adopted are SBES and DES that can resolve the turbulence scale.

[0046] It should be noted that the numerical simulation continues until the difference between the inlet and outlet flows stabilizes at less than 1% of the mainstream flow rate and changes by less than 2% of the mainstream flow rate over time, which indicates that the simulation has converged, as Figure 3 shown

[0047] Among them, SBES is the stress-blended eddy simulation, DES is the detached eddy simulation, and CFD is computational fluid dynamics;

[0048] SBES is a hybrid turbulence model that combines the characteristics of large eddy simulation (LES) and Reynolds-averaged Navier-Stokes (RANS) methods. In the near-wall region, SBES uses the RANS model to solve the flow within the boundary layer, which helps reduce the computational cost and provides accurate wall stress information; in the region far from the wall, SBES switches to the LES mode to capture large-scale turbulence structures and provide more detailed flow details. This hybrid method allows for a more accurate simulation of turbulent flows while maintaining computational efficiency;

[0049] DES is a special LES method that automatically switches to the RANS mode in the near-wall region and uses LES in the region far from the wall. The key to DES is its ability to automatically identify and switch to the appropriate turbulence model without relying on user-defined switching criteria. Near the wall, DES can provide accuracy similar to that of RANS, while in the region far from the wall, it can capture large-scale turbulence structures. DES is particularly suitable for simulating complex flow separation and transition phenomena that are difficult to accurately predict using traditional RANS models.

[0050] In this solution, SBES is selected for data simulation, and the specific simulation process is as follows:

[0051] In the near-wall region, SBES uses the RANS equations to simulate turbulence. The RANS equations are obtained by time-averaging the Navier-Stokes equations. Among them, the specific formulas of the RANS equations are as follows:

[0052]

[0053] Among them, is the average density, is the average velocity component, is the average pressure, and μ is the dynamic viscosity, is the Reynolds stress tensor;

[0054] In the region far from the wall, SBES switches to the LES equation. The LES equation is obtained by filtering the Navier - Stokes equations, and the specific formula of the LES equation is as follows:

[0055]

[0056] Among them, and are the filtered velocity and pressure respectively, is the sub - grid stress tensor;

[0057] The SBES model uses a blending function to smoothly transition between the RANS and LES regions. This blending function is based on the wall distance and the turbulence length scale, and the formula of the blending function is as follows:

[0058]

[0059] Among them, Δ is the grid size, and L r is the turbulence length scale. The value of f approaches 1 (RANS behavior) in the near - wall region and approaches 0 (LES behavior) in the region far from the wall.

[0060] Furthermore, the maximum height value of the tip separation flow is determined by analyzing the data within the entire axial range in the axial velocity distribution contour map to obtain the maximum value of the separation flow height.

[0061] It should be noted that according to the maximum height value of the tip separation flow (h max ), the transition fillet radius (r) from the blade body to the tip is designed. Usually, r is between 0.6 and 1.5 times of h max with the aim of reducing flow separation through a smooth transition.

[0062] Furthermore, the smooth transition treatment is used to suppress the separation flow caused by tip leakage.

[0063] Specifically, taking the first - stage rotor of the high - pressure compressor of a certain gas turbine as an example, the specific treatment method is as follows:

[0064] For a gas turbine compressor rotor with a tip clearance height of 1.4 mm, a computational domain and computational grid including the tip clearance region are established, such that the near - wall grid scale on the blade surface and the tip region reaches 1×10 -6magnitude;

[0065] For the above-mentioned computational domain and computational grid, the hub, casing, and blade surfaces are given as solid walls in the computational fluid dynamics solver. The total temperature, total pressure, and flow angle are given at the inlet of the computational domain, and the pressure condition at the design point is given at the outlet of the computational domain;

[0066] The SBES model is selected to perform numerical simulation on this computational model until the difference between the inlet and outlet flows is less than 1%, and the mainstream flow rate is 20.5 kg / s, and the change with time is less than 2% of the mainstream flow rate;

[0067] For the above-converged numerical simulation results, a post-processing software is used to obtain the contour map of the axial velocity distribution of the flow field at the cross-section at each axial position at the blade tip;

[0068] As Figure 4 shown, the blade tip separation region is determined based on the local axial velocity distribution contour map, and the blade tip separation flow height h is obtained;

[0069] Based on the blade tip separation flow height h at each axial position, the maximum value h of the separation flow height within the axial range of the blade tip is obtained max is 0.4 mm, which is about 30% of the blade tip clearance height;

[0070] According to the width w of the blade tip separation flow, the transition fillet radius from the blade body to the blade tip is determined, and the formula is as follows:

[0071] r = 1.25w = 0.5 mm

[0072] Through the transition fillet with a radius of r, the blade body and the blade tip are smoothly transitioned to form the blade shape after blade tip treatment, as Figure 5 shown.

[0073] For the gas turbine compressor rotor blade designed according to the above method, the fillet size for the smooth transition from the blade body to the blade tip is designed according to the scale of the blade tip separation flow. The fillet reduces the blade tip flow separation height by 40% and the width by 20%, reducing the additional loss caused by the separation flow.

[0074] Some design parameters of a certain gas turbine high-pressure compressor rotor used in this example are shown in Table 1:

[0075]

[0076] Table 1 Some design parameters of the first-stage rotor of a certain gas turbine high-pressure compressor

[0077] In summary, the present invention arranges the transmitting coil connected in reverse series and the receiving coil at the midpoint on the same plane, effectively weakening the primary field interference, accurately detecting the early secondary field signal, and improving the accuracy of grounding grid corrosion detection. The three coils are coplanar and have a simple structure, ensuring a large transmitting magnetic moment and high detection sensitivity. Through the apparent resistivity profile, the corrosion location and degree can be accurately determined, providing a scientific basis for the maintenance of the grounding grid.

[0078] Embodiment 2

[0079] This embodiment provides a computer device, which can be a terminal, and its internal structure diagram can be as Figure 3 shown. The computer device includes a processor, a memory, a communication interface, a display screen, and an input device connected through a system bus. Among them, the processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The communication interface of the computer device is used to communicate with an external terminal in a wired or wireless manner, and the wireless manner can be implemented through WIFI, a carrier network, NFC (Near Field Communication), or other technologies. When the computer program is executed by the processor, it realizes a method and system for on-line independent drive test of a target solenoid valve in a thermal power plant. The display screen of the computer device can be a liquid crystal display screen or an electronic ink display screen, and the input device of the computer device can be a touch layer covering the display screen, or a button, a trackball, or a touchpad provided on the outer shell of the computer device, or an external keyboard, a touchpad, or a mouse, etc.

[0080] This embodiment also provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, it realizes: constructing and training a target network model, where the target network model includes an edge extraction sub-module, a dynamic selection sub-module, a feature extraction sub-module, and an image enhancement sub-module; processing a degraded underground cable X-ray image through the target network model and generating a fused feature map; inputting the fused feature map into the image enhancement sub-module to generate an enhanced underground cable X-ray image.

[0081] Importantly, it should be noted that the construction and arrangement of the present application shown in multiple different exemplary embodiments are merely illustrative. Although only a few embodiments are described in detail in this disclosure, those who refer to this disclosure should easily understand that many modifications are possible without materially departing from the novel teachings and advantages of the subject matter described in this application (such as installation arrangements, use of materials, color, orientation changes, etc.). For example, an element shown as integrally formed may be composed of multiple parts or elements, the position of the element may be inverted or otherwise changed, and the nature, number, or position of discrete elements may be altered or changed. Accordingly, all such modifications are intended to be included within the scope of the present invention. The order or sequence of any process or method steps may be changed or reordered according to alternative embodiments. In the claims, any "means-plus-function" clause is intended to cover the structures that perform the functions described herein, and not only structural equivalents but also equivalent structures. Other substitutions, modifications, changes, and omissions may be made in the design, operating conditions, and arrangement of the exemplary embodiments without departing from the scope of the present invention. Therefore, the present invention is not limited to a particular embodiment, but extends to various modifications that still fall within the scope of the appended claims.

[0082] In addition, in order to provide a concise description of the exemplary embodiments, all features of the actual embodiments may not be described.

[0083] It should be understood that in the development of any actual implementation, as in any engineering or design project, numerous specific implementation decisions may be made. Such development efforts may be complex and time-consuming, but for those of ordinary skill in the art who benefit from this disclosure, without excessive experimentation, the development efforts will be a routine task of design, manufacturing, and production.

[0084] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention may be modified or equivalently replaced without departing from the spirit and scope of the technical solutions of the present invention, and they should all be covered within the scope of the claims of the present invention.

Claims

1. A compressor blade tip treatment method for suppressing blade tip separation loss, characterized in that: include, For a gas turbine compressor rotor with a specified clearance height, create a detailed computational domain and mesh including the blade tip clearance area; Set reasonable boundary conditions through computational fluid dynamics solver; According to the boundary conditions, the computational model is numerically simulated by a turbulence model that resolves the turbulence scale; Analyze the numerical simulation results to obtain the axial velocity distribution cloud diagram of the flow field at each axial position of the blade tip; The height of the blade tip separation flow is obtained from the axial velocity distribution cloud map, and the transition fillet radius from the blade body to the blade tip is designed according to the maximum height value of the blade tip separation flow; The blade body and blade tip are smoothly transitioned by the designed transition fillet radius.

2. The compressor blade tip processing method for suppressing blade tip separation loss according to claim 1, characterized in that: The computational domain refers to a precise computational domain that needs to be constructed in order to simulate the blade tip clearance region of a gas turbine compressor rotor, which includes the blade tip clearance.

3. The compressor blade tip processing method for suppressing blade tip separation loss according to claim 2, characterized in that: The meshing includes creating a computational mesh in the computational domain, and the mesh region includes a blade surface and a blade tip region.

4. The compressor blade tip processing method for suppressing blade tip separation loss according to any one of claims 2 or 3, characterized in that: The boundary conditions include solid wall conditions and inlet and outlet conditions, which simulate the environment in which the actual compressor is running.

5. The compressor blade tip processing method for suppressing blade tip separation loss according to claim 4, characterized in that: The solid wall surface includes a hub, a casing, and a blade surface; the inlet and outlet conditions include total temperature, total pressure, airflow angle, and outlet static pressure.

6. The compressor blade tip processing method for suppressing blade tip separation loss according to claim 5, characterized in that: The numerical simulation is performed using a CFD solver, and the turbulence model adopts SBES and DES that can resolve the turbulence scale.

7. The compressor blade tip processing method for suppressing blade tip separation loss according to claim 6, characterized in that: The maximum height value of the blade tip separation flow is determined by analyzing the data in the entire axial range in the axial velocity distribution cloud diagram to determine the maximum value of the separation flow height.

8. The compressor blade tip processing method for suppressing blade tip separation loss according to claim 7, characterized in that: The smooth transition process is used to suppress the separation flow caused by blade tip leakage.

9. A computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 8 are implemented.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 8 are implemented.

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