Turbine blade ablation characteristic and gas thermal performance change simulation method and system

Abstract

The invention relates to the technical field of gas turbine blade operation maintenance and gas-heat design, in particular to a turbine blade ablation characteristic and gas-heat performance change simulation method and system.The method comprises the steps that a turbine fluid-solid computational domain is constructed, grid division is conducted, boundary conditions are set based on the Fluent dynamic grid technology, and steady flow thermal coupling numerical simulation is conducted. The method comprises the steps of obtaining physical information of a computational domain at the current moment, screening and determining the position where overtemperature ablation occurs, obtaining information such as the temperature and heat flux density of a fluid-solid interface, calculating the ablation speed, achieving deformation of a grid unit of the fluid-solid interface, obtaining the geometric morphology of a blade at the current moment, and solving an unsteady flow field again. And obtaining a series of turbine blade cascade gas thermal performance and blade geometric morphology characteristics changing along with time in the ablation process until the total time t of numerical prediction simulation is reached, thereby realizing the dynamic ablation process of the gas turbine blade under the condition of high-temperature incoming flow and numerical prediction of the influence of ablation on the aerodynamic heat transfer performance of the turbine.

Description

Technical Field

[0001] The present invention relates to the technical field of operation and maintenance of gas turbine blades and gas thermal design, and specifically relates to a simulation method and system for ablation characteristics and gas thermal performance changes of turbine blades. Background Technique

[0002] Gas turbines and aeroengines are of great strategic significance in economic development. Among them, ablation of turbine blades occurs from time to time throughout the service life cycle. Blade ablation is closely related to the performance, reliability, and economy of the turbine, and poses severe challenges to blade cooling design, service operation, and later maintenance. To further improve the engine performance, even though the current advanced turbine inlet temperature has reached 2200K, its inlet temperature continues to increase. In a high-temperature and high-load working environment, areas such as the leading edge, trailing edge, and tip of the turbine blade are in a high heat load state for a long time and are prone to ablation, resulting in changes in geometric characteristics and roughness, thereby causing the gas thermal performance of the turbine to degrade, seriously affecting the safety of the operation of the turbine and even the gas turbine system. To accurately calculate the ablation amount of the blade and estimate the working life of the turbine, it is very necessary to study the ablation mechanism of the blade throughout the service life cycle and the resulting gas thermal characteristic change law. Conducting experimental research on high-temperature ablation of turbine blades is the most powerful and reliable research method. However, in terms of experimental research, since the temperature in the ablation area of the real gas turbine blade is above 1390K and the entire ablation process lasts for thousands of hours, there is currently no ablation experiment directly carried out on metal blades, and the high-temperature experiment itself has disadvantages such as high difficulty, high cost, limited geometric dimensions of the test piece, and limited test measurement means. Based on this, developing a numerical prediction method for high-temperature ablation of turbine blades and fluid-thermal coupling of cascades is the current frontier and difficulty in domestic and foreign research.

[0003] To avoid ablation, current research on turbine blade overtemperature mostly focuses on blade cooling and heat transfer in order to solve the problem of excessive temperature. However, the ablation problem is essentially a complex change process, including phase change, moving interfaces, various physical and chemical reactions, and coupling between different physical fields, etc. So far, the ablation characteristics, influencing factors, and occurrence mechanism of turbine blades are still unclear.

[0004] Currently, the theoretical and numerical research on blade ablation in the open literature generally falls into the following five stages: The first stage is to calculate the blade ablation numerically through a small number of simplified models and calculations, as well as a small number of empirical correlation calculations based on engine service data. This method has strong limitations and cannot be applied to the ablation research of different types of engine blades; The second stage is to predict the ablation area through ablation maintenance, fault troubleshooting, and intelligent algorithms. This method highly relies on engineering experience but lacks systematic theoretical support and scientific basis, and the subjectivity and uncertainty of the prediction results are relatively large; The third stage is to simulate the ablation distribution law on the blade surface, which needs to be realized through an open-source system and self-written programs. It is highly complex and difficult, requiring a large amount of time and effort for development and debugging, and it is difficult to guarantee the stability and reliability of the program; The fourth stage is to achieve ablation recession by deleting elements through the Abaqus birth and death element method. This method faces problems such as whether the solid field information can be transferred to the flow field in a timely manner during the calculation; The fifth stage is to analyze the influence of blade ablation on the flow field through user-defined functions combined with dynamic mesh technology. However, the existing calculations only support two-dimensional computational domains, while blade ablation is a three-dimensional problem. The two-dimensional computational domain cannot accurately simulate the geometric shape of the blade and the complex flow characteristics of the flow field, resulting in a large difference between the calculation results and the actual situation, and the melting properties of the blade material itself are not considered, so the blade ablation situation cannot be accurately obtained. Summary of the Invention

[0005] Aiming at the problem of poor accuracy in numerical simulation of high-temperature ablation of turbine blades in the high-temperature incoming flow working environment of gas turbines in the existing technology, the present invention provides a method and system for simulating the ablation characteristics and gas thermal performance changes of turbine blades.

[0006] To achieve the above object, the present invention adopts the following technical solutions: A method for simulating the ablation characteristics and gas thermal performance changes of a turbine blade, including, S1. Construct a fluid-solid computational domain of a gas turbine blade and perform mesh division; S2. Based on the Fluent dynamic mesh technology, apply boundary conditions to the fluid-solid computational domain and perform steady-state fluid-thermal coupling numerical simulation to solve, set the initial time t = 0, and define the time step Δ t , and obtain the physical field information of the fluid-solid computational domain at the current time t; S3. Based on the physical field information of the fluid-solid computational domain, identify the over-temperature region at the fluid-solid interface, extract the ablation-related parameters in the over-temperature region, and store them on the grid cell surface; S4. According to the ablation-related parameters, calculate the ablation rate of the over-temperature region of the turbine blade based on the energy conservation equation and the latent heat of phase change; S5. Distribute the obtained ablation rate to the grid nodes, and according to the ablation rate and the time step Δt Move the grid nodes on the moving fluid-structure interface, and after smoothing the grid, output the current blade ablation morphology; S6. Based on the current blade ablation morphology, perform iterative calculations through steady-state fluid-thermal coupling and update the time ; S7. Loop through S2 - S6 until the preset total time T is reached, and output the gas-thermal performance of the turbine cascade and the blade geometric morphology characteristics varying with time during the ablation process.

[0007] Preferably, the fluid-structure calculation domain includes a fluid domain and a solid domain; unstructured grids are used for meshing the fluid-structure calculation domain, and the grid nodes on the interface between the fluid domain and the solid domain correspond one by one.

[0008] Preferably, the specific process of solving the steady-state fluid-thermal coupling numerical simulation in S2 is as follows: The steady-state fluid-thermal coupling numerical simulation is solved in the Fluent solver. To achieve data exchange in different regions, the fluid-structure interface is set as the coupling boundary, and the physical field information of the fluid-structure calculation domain of the continuous phase in the turbine blade cascade is obtained by solving the three-dimensional unsteady Reynolds-averaged Navier-Stokes equations.

[0009] Preferably, the range of the time step Δ t is [0.5h, 2h].

[0010] Preferably, the ablation-related parameters in the over-temperature region include the temperature, heat flux density at the fluid-structure interface, the temperature gradient in the solid domain of the calculation domain, and the relevant parameters of the grid cell surface area.

[0011] Preferably, the calculation formula for the ablation rate in the over-temperature region of the turbine blade in S4 is:

[0012] In the formula: v is the high-temperature ablation rate of the turbine blade, with the unit of m / s; wall_heat_flux is the wall heat flux, with the unit of W; A is the grid surface area of the fluid-structure interface, with the unit of m 2 ; k is the thermal conductivity of the blade material, with the unit of ; T w is the surface temperature of the turbine blade, with the unit of K; ρ is the density of the turbine blade material, with the unit of kg / m 3 ; L is the latent heat of fusion of the turbine blade material, with the unit of .

[0013] Preferably, the moving speed of the grid nodes on the fluid-solid interface in S5 is adjusted by using a magnification factor The expression is:

[0014] In the formula: the moving speed of the grid cell nodes v ', v is the high-temperature ablation speed of the turbine blade.

[0015] A simulation system for turbine blade ablation characteristics and gas thermal performance changes includes: A fluid-solid calculation domain construction module for constructing the fluid-solid calculation domain of a gas turbine blade and performing mesh division; A physical field acquisition module for applying boundary conditions to the fluid-solid calculation domain according to the operating conditions of the gas turbine, performing a steady-state fluid-thermal coupling numerical simulation to solve, setting the initial time t = 0, defining the time step Δ t , and obtaining the physical field information of the fluid-solid calculation domain at the current time t; An identification and extraction module for identifying the over-temperature area of the fluid-solid interface based on the physical field information of the fluid-solid calculation domain, extracting the ablation-related parameters of the over-temperature area, and storing them on the grid cell surface; An ablation speed calculation module for calculating the ablation speed of the over-temperature area of the turbine blade based on the relevant parameters, the energy conservation equation, and the latent heat of phase change; A blade ablation morphology output module for distributing the obtained ablation speed to the grid nodes, moving the grid nodes on the fluid-solid interface according to the ablation speed and the time step Δ t , and performing smoothing processing on the grid, and then outputting the current blade ablation morphology; A steady-state fluid-thermal coupling update and iteration module for performing iterative calculations and updating the time through steady-state fluid-thermal coupling based on the current blade ablation morphology ; A turbine blade ablation performance output module for outputting the gas thermal performance and blade geometric morphology characteristics of the turbine cascade that change with time during the ablation process.

[0016] A terminal device includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the steps of a simulation method for turbine blade ablation characteristics and gas thermal performance changes.

[0017] A computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, it implements the steps of a simulation method for turbine blade ablation characteristics and gas thermal performance changes.

[0018] Compared with the prior art, the present invention has the following beneficial effects: The present invention provides a simulation method for the ablation characteristics and the change of gas thermal performance of a turbine blade. A turbine fluid-solid computational domain is constructed and meshed. Based on the Fluent dynamic mesh technology, boundary conditions are set, and a steady-state fluid-thermal coupling numerical simulation is carried out to obtain various physical information of the computational domain at the current moment. The positions where over-temperature ablation occurs are screened and determined, and information such as the temperature and heat flux density at the fluid-solid interface is obtained. The previous physical quantity information is stored and the ablation rate is calculated and stored, and the mesh element deformation at the fluid-solid interface is realized to obtain the blade geometry at the current moment, and then the unsteady flow field is solved again until the total time of the numerical prediction simulation is reached. t During this process, a series of gas thermal performance of the turbine cascade and the blade geometry characteristics changing with time during the ablation process are obtained, realizing the numerical prediction of the dynamic ablation process of the gas turbine blade under high-temperature incoming flow conditions and the influence of ablation on the gas turbine aerodynamic heat transfer performance. This application comprehensively considers the interaction between blade ablation and the flow field, the data transfer method at the fluid-solid interface, and the material properties of the turbine blade, and can accurately simulate the ablation physical process. It has the advantages of low cost and high precision in solving the problem of high-temperature ablation of turbine blades, and can be used as an efficient gas thermal design analysis and design tool for gas turbine blades considering high-temperature ablation.

[0019] The present invention also provides a terminal device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the steps of the above method are realized; the processor can quickly execute processes such as the simulation of the ablation characteristics and the change of gas thermal performance of the turbine blade as described above; the computer program in the memory can be modified and optimized according to actual needs to adapt to different requirements for the simulation of the ablation characteristics and the change of gas thermal performance of the turbine blade.

[0020] A computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the above method are realized; the computer-readable storage medium (such as a solid-state drive (SSD) and a Flash memory) has a high-speed reading ability, can quickly load the computer program into the processor for execution, and ensures the simulation of different ablation characteristics and the change of gas thermal performance of the turbine blade. It has the characteristics of flexibility and portability, high reliability and stability, support for large-scale data storage, easy integration and expansion, reduction of development and maintenance costs, high security, energy conservation and environmental protection, support for multiple application scenarios, and promotion of standardization and normalization, providing strong support for the simulation of different ablation characteristics and the change of gas thermal performance of the turbine blade, and having a wide application prospect. Description of the Drawings

[0021] Figure 1Schematic diagram of a simulation method for ablation characteristics and gas thermal performance changes of a turbine blade according to the present invention.

[0022] Figure 2 Temperature prediction results after high-temperature ablation occurs at the trailing edge of a two-dimensional turbine blade in an embodiment of the present invention. Among them, (a), (b), (c), and (d) are the prediction results at 5 time steps, 40 time steps, 80 time steps, and 120 time steps of ablation respectively. Among them, 1 is the trailing edge profile of the blade before ablation, and 2 is the trailing edge profile of the blade after ablation.

[0023] Figure 3 Temperature prediction results after high-temperature ablation occurs at the leading edge of a two-dimensional turbine blade in an embodiment of the present invention. Among them, (a), (b), (c), and (d) are the prediction results at 5 time steps, 40 time steps, 80 time steps, and 120 time steps of ablation respectively. Among them, 3 is the leading edge profile of the blade before ablation, and 4 is the leading edge profile of the blade after ablation.

[0024] Figure 4 Schematic diagram of grid deformation before and after high-temperature ablation occurs at the trailing edge of a two-dimensional turbine blade in an embodiment of the present invention. (a) and (b) are schematic diagrams of the grids near the trailing edge before and after ablation respectively. Among them, 5 is the trailing edge profile of the blade before ablation, 6 is the trailing edge profile of the blade after ablation, and the arrows in the figure are the grid movement directions.

[0025] Figure 5 Schematic diagram of grid deformation before and after high-temperature ablation occurs at the leading edge of a two-dimensional turbine blade in an embodiment of the present invention. (a) and (b) are schematic diagrams of the grids near the leading edge before and after ablation respectively. Among them, 5 is the leading edge profile of the blade before ablation, 6 is the leading edge profile of the blade after ablation, and the arrows in the figure are the grid movement directions.

[0026] Figure 6 Three-dimensional morphology prediction results after high-temperature ablation occurs at the leading edge of a three-dimensional turbine blade in an embodiment of the present invention. Among them, 9 is the three-dimensional morphology of the blade before ablation, and 10 is the three-dimensional morphology of the blade after ablation. Detailed implementation manners

[0027] In order to enable those skilled in the art to better understand the solution of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0028] The present invention discloses a simulation method for ablation characteristics and gas thermal performance changes of a turbine blade. Refer to Figure 1 , and specifically includes the following steps: Step 1: Take the gas turbine blade as the research object, construct the fluid-structure calculation domain of the gas turbine blade, and perform mesh division on the fluid-structure calculation domain. The fluid-structure calculation domain includes the calculation domains of the fluid domain and the solid domain; Step 2: According to the operating conditions of the gas turbine, simplify the high-temperature gas into an ideal gas, only consider high-temperature ablation, apply boundary conditions to the mesh of the fluid-structure calculation domain, select a suitable turbulence model and the mesh division size of the calculation domain after turbulence model verification and mesh independence verification, and then perform steady-state fluid-thermal coupling numerical simulation to solve. When the calculation result converges, set this moment as the initial moment t = 0, t is the time for the current unsteady calculation, Δ t is the time step size Δ defined for the ablation unsteady calculation t , and the value range of the calculated time step size is given according to the life cycle of the gas turbine blade itself: Δ t = [0.5h, 2h]; Among them, in order to realize data exchange in different regions, the fluid-structure interface is set as the coupling boundary; the steady-state fluid-thermal coupling numerical simulation is completed in the Fluent solver, and the physical field information of the fluid-structure calculation domain of the continuous phase in the cascade of the turbine blade is obtained by solving the three-dimensional unsteady Reynolds-averaged Navier-Stokes equations (URANS); Step 3: Obtain the physical quantity information of the fluid-structure calculation domain according to the solution result at the current moment t , including: the solid surface temperature, heat flux, heat flux density, temperature gradient and grid cell surface area in the ablation area; Step 4: According to the temperature field information of the solid domain in the physical field information of the fluid-structure calculation domain, screen out the over-temperature area of the fluid-structure interface, determine the location of over-temperature ablation, and obtain the relevant parameters of the temperature, heat flux density, temperature gradient of the solid domain in the calculation domain and the grid cell surface area at the fluid-structure interface; Specifically: Through the regional determination of the molten layer of the high-temperature part of the blade in the steady-state fluid-thermal coupling numerical calculation and the acquisition of the state parameters of the molten layer - boundary layer, judge the solid domain surface where ablation occurs by whether the surface temperature of the solid domain reaches the melting point temperature, screen out the over-temperature area of the fluid-structure interface, determine the area where over-temperature ablation occurs, and store the information of the over-temperature ablation area in the grid cell; Step 5: For the over-temperature area determined in Step 4, store the physical quantity information of the fluid-structure interface obtained in Step 4 in the grid cells adjacent to the fluid-structure interface. According to this information, solve the high-temperature ablation velocity of the blade through the energy conservation equation and the latent heat of phase change. The specific calculation method is:

[0029] In the formula: v is the high-temperature ablation velocity of the blade (m / s), wall_heat_fluxis the wall heat flux (W), A is the grid surface area of the interface (m 2 ), k is the thermal conductivity of the blade material ( ), T w is the blade surface temperature (K), ρ is the density of the blade material (kg / m 3 ), L is the latent heat of fusion of the material (kJ / kg). The high-temperature ablation rate of the blade in the solid over-temperature ablation region will be obtained v and then stored on the moving mesh cell face; It is assumed that the gas turbine blade material is the nickel-based single crystal alloy DD6, and an energy conservation equation is established at the wall position:

[0030]

[0031]

[0032] In the formula: q s is the heat flux entering the metal from the wall (W), q m is the heat flux required for melting (W), T w is the blade surface temperature (K), ρ is the density of the blade material (kg / m 3 ), L is the latent heat of fusion of the material (kJ / kg), v is the wall melting rate (m / s), k is the thermal conductivity of the blade material ( ).

[0033] The high-temperature ablation model is based on the thermal equilibrium integral method, and the ablation rate is solved according to the heat flux density of the solid wall; considering that the gas turbine blade material is the nickel-based single crystal alloy DD6, this alloy has the characteristics of high strength and high toughness, and its ablation mechanism is of the melting type, that is, due to aerodynamic heating, the surface temperature of the object rises to the melting point, and the surface substance melts to form a fluid layer, and the ablation problem of the blade is solved by means of the phase change heat conduction problem.

[0034] Step 6: Distribute the ablation rate to each node of the mesh cell, and move the mesh nodes on the fluid-solid interface according to the high-temperature ablation rate of the blade and the set time step Δ t According to the mesh nodes on the interface between the moving fluid domain and the solid domain, realize the boundary deformation of the fluid domain and the solid domain due to ablation occurring simultaneously; Store information such as the solid surface temperature, heat flux, temperature gradient, and ablation rate in the ablation area in the grid cells of the solid domain where ablation occurs. The storage of the above data in the grid cells, grid walls, and nodes, as well as the information transfer, are achieved through the user-defined memory macro commands in Fluent.

[0035] Here, is the total time simulated by numerical prediction in a short time T Complete the simulation of blade ablation under high-temperature operating conditions of a gas turbine with a long time span. To accelerate the numerical simulation process of blade ablation under the actual high-temperature takeoff condition, a magnification factor for the grid movement speed is given, and the given magnification factor C The value range is [10, 50], then the movement speed of the grid nodes v ' is:

[0036] Step 7: Smooth the grid of the computational domain according to the degree of deformation of the fluid-structure interface, so as to obtain the grid of the computational domain after ablation in a single time step. At the same time, output the fluid-structure interface grid at the current time step as the blade geometry at the current moment.

[0037] The movement of the grid nodes on the interface between the fluid domain and the solid domain after ablation is realized through the dynamic grid smoothing and reconstruction in Fluent; the movement distance, speed, and direction of the grid nodes are controlled by user-defined functions.

[0038] The grid smoothing process includes: using the spring approximation method combined with the Laplace smoothing algorithm to perform collaborative grid reconstruction on the deformed fluid domain and solid domain; Step 8: Use the unsteady flow-thermal coupling method to perform numerical calculations on the grid of the computational domain obtained in the previous step and accumulate the time step Δ t at the current calculation time t and update the time ; Step 9: Repeat steps 3 to 8 to obtain the physical field information of the change of the fluid-structure computational domain in the case of blade ablation until reaching the total time T of the numerical prediction simulation.

[0039] Step 10: According to steps 3 - 7 repeated in a loop, obtain a series of gas-thermal performance and blade geometry characteristics of the turbine cascade that change with time during the blade ablation process.

[0040] Embodiment 1 The technical solution adopted by the present invention to solve the above problems is: a numerical calculation method for gas turbine blade ablation based on Fluent dynamic grid technology, including the following steps: The film cooling holes on the blade surface are simplified into slots with equal areas. This step is completed by the projection plane conversion method. During the conventional calculation of the flow field and temperature field of a certain gas turbine first-stage moving blade cascade under the working environment of high-temperature gas, it is found that there is an over-temperature area at the blade tip. According to the first-stage moving blade of the certain gas turbine, the geometric model is drawn and simplified. The solid calculation domain is simplified by taking 40% of the original blade height as the current solid calculation domain. The geometric model file is imported into the fluid simulation software and the computational grid is meshed. The geometric model and grid include the high-temperature gas fluid domain, the cold air inlet, the blade solid region, and the fluid-solid interface region; Taking the high-temperature operating condition of this gas turbine as the boundary condition, after verifying the turbulence model, the standard turbulence model is selected. After verifying the grid independence, the specific grid division size is determined: the number of expansion layers of the boundary layer near the wall surface in the fluid domain is 15 layers, the thickness of the first layer is 0.002 mm, the growth rate is 1.1, the number of grid cells in the computational domain is about 18 million, and the grid division uses unstructured grids. The grid nodes on the interface between the fluid domain and the solid domain are completely in one-to-one correspondence. To realize data exchange in different regions, the fluid-solid interface is set as the coupling boundary. After initializing the fluid-solid computational domain, the physical field information of the fluid-solid computational domain is calculated; The high-temperature ablation model is based on the heat balance integral method proposed by Landau et al., and the ablation rate is solved according to the heat flux density on the solid wall surface. In this paper, the material of the gas turbine blade is the nickel-based single crystal alloy DD6, and its ablation mechanism is of the melting type, that is, due to aerodynamic heating, the surface temperature of the object rises to the melting point, and the surface substance melts to form a fluid layer. The high-temperature ablation model is applied to the blade surface through UDF, and whether ablation occurs is judged by whether the surface reaches the melting point temperature.

[0041] After ablation occurs, information such as the blade surface temperature, heat flux density, temperature gradient, and grid cell area is stored in the grid cells through the Fluent user-defined storage macro command UDM, and the grid movement speed on the wall surface is obtained.

[0042] The grid movement speed of the ablated grid cells is calculated as follows:

[0043] In the formula, v is the node movement rate (m / s), q is the wall heat flux read by UDF (W), A is the surface area of the grid cell (m 2 ), k is the thermal conductivity of the blade material ( ), T is the wall temperature, ρ [[ID=3C]]is the density of the blade material (kg / m 3 ), L is the latent heat of fusion of the material (kJ / kg).

[0044] After calculating the moving speed of the grid points that have moved, the data storage and transfer on the fluid-structure interface are realized, and the dynamic grid program is controlled through the node movement macro of UDF.

[0045] Execute the dynamic grid program in Fluent. The grid smoothing and reconstruction in Fluent realize the movement of grid nodes. The user-defined function calculates and controls the moving speed and direction of grid nodes. Set the dynamic grid update in Dynamic Mesh, select the area near the fluid-structure interface, set the update method to Remeshing, and select relevant parameters in Dynamic Mesh Parameters to ensure that the grid is updated as the grid moves and changes.

[0046] To accelerate the numerical simulation process of blade ablation under actual high-temperature takeoff conditions, a magnification factor of the grid moving speed is given, and the magnification factor is used to adjust the moving speed of the grid cell nodes;

[0047] where: the moving speed of the grid cell nodes v ', v is the high-temperature ablation speed of the turbine blade.

[0048] Adopt the same unsteady flow-thermal coupling numerical simulation method as before, re-solve the flow field, realize the simultaneous boundary deformation of the fluid domain and the solid domain due to blade ablation, and obtain the flow field information of blade ablation under the influence of high-temperature gas until t reaching the total time of the numerical prediction simulation T .

[0049] Calculation results: Through the above method, the prediction results of the geometric shape change of the turbine blade with ablation are realized. The temperature prediction results after high-temperature ablation at the trailing edge and leading edge of the turbine blade are obtained, as Figure 2 , Figure 3 shown. The schematic diagrams of the grid deformation in the calculation domain after high-temperature ablation at the trailing edge and leading edge of the turbine blade are obtained, as Figure 4 , Figure 5 shown. The three-dimensional morphology schematic diagram after high-temperature ablation at the trailing edge of the turbine blade is obtained, as Figure 6 shown.

[0050] In summary, the present invention provides a numerical calculation method for simulating blade ablation. Considering that existing methods only consider the action of high-temperature gas and it is difficult to take into account the melting characteristics of the blade material itself, the numerical simulation results are relatively rough, or the calculation model is only applicable to calculation domains with a very small number of grids and two-dimensional calculation domains. The present invention considers the heat convection at the fluid-solid interface and the heat conduction on and inside the solid surface under the action of high-temperature gas, takes into account the physical properties of the blade material and the latent heat of phase change, realizes the control of the grid movement at the fluid-solid interface according to the parameters of the ablation area, and ensures that the grid quality of the discrete domain of the fluid-thermal coupling numerical calculation within the studied ablation amount range meets the requirements of calculation stability and accuracy by adjusting the grid deformation parameters. During the calculation process, the deformation of the fluid-solid boundary at each time step participates in the numerical calculation of the gas-thermal coupling, forming a multi-physics field coupling algorithm for flow, heat transfer, and ablation. Compared with the current research that can only roughly judge the possible ablation area through the blade temperature and uses whether the temperature exceeds the melting point as the primary indicator for evaluating and improving the cooling design, it can more accurately obtain the interaction mechanism between ablation and gas-thermal characteristics, quantitatively calculate its ablation characteristics and the process of gas-thermal performance degradation, and provide a solid scientific basis for the cooling design, life prediction, and economic improvement of turbine blades. The method of the present invention can also be directly applied to the analysis of material ablation problems in hot-end components such as aero-engine combustors and ground gas turbine combustors.

[0051] The present invention provides a simulation system for the ablation characteristics and gas-thermal performance changes of a turbine blade, including: A fluid-solid calculation domain construction module, used to construct the fluid-solid calculation domain of the gas turbine blade and perform grid division; A physical field acquisition module, used to apply boundary conditions to the fluid-solid calculation domain according to the operating conditions of the gas turbine, perform a steady-state fluid-thermal coupling numerical simulation to solve, set the initial time t = 0, define the time step Δ t , and obtain the physical field information of the fluid-solid calculation domain at the current time t; An identification and extraction module, used to identify the over-temperature area at the fluid-solid interface based on the physical field information of the fluid-solid calculation domain, extract the ablation-related parameters of the over-temperature area, and store them on the grid cell surface; An ablation velocity calculation module, which calculates the ablation velocity of the over-temperature area of the turbine blade based on the energy conservation equation and the latent heat of phase change according to the relevant parameters; A blade ablation morphology output module, used to distribute the obtained ablation velocity to the grid nodes, move the grid nodes on the fluid-solid interface according to the ablation velocity and the time step Δ t , and after smoothing the grid, output the current blade ablation morphology; A steady-state fluid-thermal coupling update and iteration module, which performs iterative calculation through steady-state fluid-thermal coupling and updates the time based on the current blade ablation morphology ; An ablation performance output module for a turbine blade, which is used to output the gas thermal performance of a turbine cascade and the blade geometric morphology characteristics that change with time during the ablation process.

[0052] The present invention provides a terminal device, which includes: a processor, a memory, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the steps in the above-mentioned method embodiments are implemented. Alternatively, when the processor executes the computer program, the functions of each module / unit in the above-mentioned device embodiments are implemented.

[0053] The computer program can be divided into one or more modules / units, and the one or more modules / units are stored in the memory and executed by the processor to complete the present invention.

[0054] The terminal device can be a computing device such as a desktop computer, a notebook, a palm computer, and a cloud server. The terminal device may include, but is not limited to, a processor and a memory.

[0055] The processor may be a central processing unit (CPU), or may also be other general-purpose processors, digital signal processors (DSPs), application specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc.

[0056] The memory can be used to store the computer program and / or module, and the processor realizes various functions of the terminal device by running or executing the computer program and / or module stored in the memory, and by calling the data stored in the memory.

[0057] If the modules / units integrated in the terminal device are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, to implement all or part of the processes in the above-described embodiment methods of the present invention, it can also be completed by a computer program instructing relevant hardware. The computer program can be stored in a computer-readable storage medium. When the computer program is executed by a processor, the steps of the above various method embodiments can be implemented. Among them, the computer program includes computer program code, and the computer program code can be in the form of source code, object code, executable file, or some intermediate form, etc. The computer-readable medium can include: any entity or device capable of carrying the computer program code, recording medium, USB flash drive, mobile hard disk, magnetic disk, optical disc, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signal, telecommunication signal, and software distribution medium, etc. It should be noted that the content included in the computer-readable medium can be appropriately increased or decreased according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, the computer-readable medium does not include electrical carrier signals and telecommunication signals.

[0058] The above are only the preferred embodiments of the present invention and are not intended to limit the technical solutions of the present invention. Those skilled in the art should understand that without departing from the spirit and principle of the present invention, the technical solutions can be subject to several simple modifications and substitutions, and these modifications and substitutions also fall within the protection scope covered by the claims.

Claims

1. A simulation method for the ablation characteristics and gas thermal performance changes of a turbine blade, characterized in that including S1. Construct the fluid-structure computational domain of the gas turbine blade and perform mesh generation; S2. Based on the Fluent dynamic mesh technology, apply boundary conditions to the fluid-structure computational domain and perform a steady-state fluid-thermal coupling numerical simulation to solve the problem. Set the initial time t = 0 and define the time step Δ t , and obtain the physical field information of the fluid-structure computational domain at the current time t; S3. Based on the physical field information of the fluid-structure computational domain, identify the over-temperature regions at the fluid-structure interface, extract the ablation-related parameters of the over-temperature regions, and store them on the mesh cell faces; S4. According to the ablation-related parameters, based on the energy conservation equation and the latent heat of phase change, calculate the ablation rate of the over-temperature regions of the turbine blade; S5. Assign the obtained ablation rate to the grid nodes, and based on the ablation rate and the time step Δ t Move the grid nodes on the fluid-structure interface, and after smoothing the grid, output the current ablation morphology of the blade; S6. Based on the current blade ablation morphology, perform iterative calculations through steady-flow thermal coupling and update the time ; S7. Loop through S2 - S6 until the preset total time T is reached, and output the gas-thermal performance of the turbine cascade and the blade geometric shape characteristics varying with time during the ablation process.

2. The simulation method for ablation characteristics and gas thermal performance change of a turbine blade according to claim 1, characterized in that The fluid-structure computational domain includes a fluid domain and a solid domain; unstructured meshes are used for mesh generation of the fluid-structure computational domain, and the mesh nodes on the interface between the fluid domain and the solid domain correspond one by one.

3. A simulation method for the ablation characteristics and gas thermal performance changes of a turbine blade according to claim 1, characterized in that The specific process of solving the steady-state fluid-thermal coupling numerical simulation in S2 is as follows: The steady-state fluid-thermal coupling numerical simulation is solved in the Fluent solver. To achieve data exchange between different regions, the fluid-structure interface is set as the coupling boundary, and the physical field information of the fluid-structure computational domain of the continuous phase in the turbine blade cascade is obtained by solving the three-dimensional unsteady Reynolds-averaged Navier-Stokes equations.

4. The simulation method for ablation characteristics and gas thermal performance changes of a turbine blade according to claim 1, characterized in that The time step Δ t ranges from [0.5 h, 2 h].

5. A simulation method for the ablation characteristics and gas thermal performance changes of a turbine blade according to claim 1, characterized in that, The ablation-related parameters of the over-temperature regions in S3 include the temperature, heat flux density at the fluid-structure interface, the temperature gradient of the solid domain in the computational domain, and the relevant parameters of the mesh cell surface area.

6. The simulation method for ablation characteristics and gas thermal performance change of a turbine blade according to claim 1, characterized in that The calculation formula for the ablation rate of the over-temperature regions of the turbine blade in S4 is: Wherein: v is the high-temperature ablation rate of the turbine blade, with the unit of m / s; wall_heat_flux is the wall heat flux, with the unit of W; A is the surface area of the fluid-solid interface grid, with the unit of m 2 ; k is the thermal conductivity of the blade material, with the unit of ; T w is the surface temperature of the turbine blade, with the unit of K; ρ is the density of the turbine blade material, with the unit of kg / m 3 ; L is the latent heat of fusion of the turbine blade material, with the unit of .

7. A simulation method for turbine blade ablation characteristics and gas thermal performance changes according to claim 1, characterized in that, The moving speed of the grid nodes on the fluid-solid interface in S5 is adjusted by using a magnification factor and the expression is: In the formula: the moving speed of the grid cell node v ', v is the high-temperature ablation speed of the turbine blade.

8. A simulation system for turbine blade ablation characteristics and gas thermal performance changes, based on the simulation method for turbine blade ablation characteristics and gas thermal performance changes according to any one of claims 1-7, characterized in that, including: A fluid-structure computational domain construction module for constructing the fluid-structure computational domain of the gas turbine blade and performing mesh generation; A physical field acquisition module, which is used to apply boundary conditions to the fluid-structure calculation domain according to the operating conditions of the gas turbine, perform a steady-state fluid-thermal coupling numerical simulation to solve, set the initial time t = 0, and define the time step Δ t , and obtain the physical field information of the fluid-structure calculation domain at the current time t; An identification and extraction module for identifying the over-temperature regions at the fluid-structure interface based on the physical field information of the fluid-structure computational domain, extracting the ablation-related parameters of the over-temperature regions, and storing them on the mesh cell faces; An ablation rate calculation module for calculating the ablation rate of the over-temperature regions of the turbine blade according to the relevant parameters based on the energy conservation equation and the latent heat of phase change; The blade ablation morphology output module is used to distribute the obtained ablation rate to the grid nodes, and based on the ablation rate and the time step Δ t move the grid nodes on the moving fluid-structure interface, and after smoothing the grid, output the current blade ablation morphology; Steady flow and heat coupling update iteration module, which based on the current blade ablation morphology, performs iterative calculations through steady flow and heat coupling and updates the time ; An ablation performance output module of the turbine blade for outputting the gas-thermal performance of the turbine cascade and the blade geometric shape characteristics varying with time during the ablation process.

9. A terminal device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the steps of the method for simulating the ablation characteristics and gas-thermal performance changes of a turbine blade as described in any one of claims 1 - 7.

10. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by the processor, it implements the steps of the method for simulating the ablation characteristics and gas-thermal performance changes of a turbine blade as described in any one of claims 1 - 7.

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