Method and apparatus for simulating low infrared band thermal emissivity of turbine blade thermal barrier coating

Abstract

The simulation method and equipment for the low infrared band thermal emissivity of a turbine blade thermal barrier coating belong to the technical field of simulation of an aero-engine, and solve the problems of low measurement precision and high cost of the low infrared band thermal emissivity of the turbine blade thermal barrier coating. The method comprises the following steps: establishing a geometric model and defining material properties of each part; setting boundary conditions of a simulation region according to a thermal barrier coating micrograph, so as to simulate electromagnetic field behaviors of an actual environment, and setting FDTD simulation conditions; setting a simulation light source and a monitor; obtaining different frequency domain electromagnetic field power distributions by sampling Poynting vectors in the simulation region, and obtaining thermal barrier coating emissivity data; changing modeling structure settings to set multiple simulation conditions, updating positions of the simulation light source and the monitor, and obtaining multiple sets of emissivity data. The present application provides guidance for subsequent preparation of the thermal barrier coating in terms of emissivity regulation.

Description

Technical Field

[0001] This application relates to the field of aero-engine simulation technology, and in particular to the emissivity of thermal protection coatings in aero-engines. Background Technology

[0002] Thermal barrier coatings (TBCs), a coating technology that combines heat insulation and protection, are typically applied to the surfaces of high-temperature resistant or superalloy turbine blades to help extend their service life in high-temperature and corrosive environments. The structure of a TBC mainly consists of a top ceramic layer and a metal binder layer. The top ceramic layer is commonly made of yttria-stabilized zirconia (YSZ) prepared using electron beam physical vapor deposition (EB-PVD). The metal binder layer is industrially commonly a Pt-Al diffusion layer produced by filler bonding or chemical vapor deposition. In high-temperature and corrosive service environments, TBCs can protect the high-temperature blade substrate, improve turbine inlet temperature and thrust-to-weight ratio, and are widely used in aerospace, energy, automotive, and industrial fields.

[0003] With the ever-increasing demand for efficiency and energy conservation, aero-gas turbine engines are developing towards higher flow rates, higher thrust-to-weight ratios, and higher turbine inlet temperatures, making them a strategic high ground that countries are vying for. The thermal load on turbine rotor blades in high-temperature gas is one of the key bottlenecks restricting the development of high thrust-to-weight ratio engine technology. A higher thrust-to-weight ratio in a turbine engine means higher engine performance and efficiency, but also higher operating temperatures for the turbine rotor blades. The high temperatures caused by high thrust-to-weight ratios can lead to a series of thermal failure problems, such as turbine rotor blade fracture and damage. Therefore, real-time temperature monitoring of engine turbine blades is one of the core technologies for improving high-performance, high thrust-to-weight ratio engines. According to Boltzmann's law E = εσT⁴, where ε is infrared emissivity, T is temperature (K), and σ is the Stefan-Boltzmann constant, to monitor the temperature of turbine engine blades, it is necessary to obtain the infrared radiation intensity and infrared emissivity of the blades. The former is usually detected using specialized experimental instruments; therefore, the key issue lies in how to determine the value of infrared emissivity.

[0004] In practical applications, the experimental method for measuring the low-infrared emissivity of thermal barrier coatings is affected by various factors, including material parameter mismatch, thermal residual stress, high-temperature sintering of ceramic materials, high-temperature fatigue, and interfacial oxidation. These issues lead to challenges such as difficult coating preparation and harsh operating environments. Furthermore, the preparation of thermal barrier coating samples of varying thicknesses requires significant time and economic costs, resulting in poor flexibility and reusability of the experimental method. Summary of the Invention

[0005] The purpose of this invention is to solve the problems of low accuracy and high cost in measuring the low infrared thermal emissivity of thermal barrier coatings on turbine blades, and to provide a method and equipment for simulating the low infrared thermal emissivity of thermal barrier coatings on turbine blades.

[0006] This invention is achieved through the following technical solution: In one aspect, this invention provides a method for simulating the low infrared thermal emissivity of a thermal barrier coating on turbine blades, the method comprising:

[0007] Step 1: Establish the geometric model of the thermal barrier coating and define the material properties of each part;

[0008] The thermal barrier coating geometric model includes a ceramic surface layer and a substrate structure consisting of a trapezoidal large column and two secondary small columns on its sides;

[0009] Step 2: Based on the micrograph of the thermal barrier coating, set the boundary conditions of the simulation area to simulate the electromagnetic field behavior of the actual environment, and at the same time set the FDTD simulation conditions;

[0010] Step 3: Set up the simulation light source and monitor, including: placing a plane wave above the thermal barrier coating geometry model, incident vertically; the monitor is used to obtain the transmittance curve;

[0011] Step 4: Perform simulation calculations and result analysis. By sampling the Poynting vector in the simulation area, the electromagnetic field power distribution in different frequency domains is obtained, and then the emissivity data of the thermal barrier coating is obtained.

[0012] Step 5: By changing the model structure, set multiple sets of simulation conditions, update the positions of the simulation light source and monitor, and obtain multiple sets of emissivity data.

[0013] Further, in step 1, the geometric model of the thermal barrier coating includes a ceramic surface layer and a substrate structure composed of a trapezoidal large column and its two side secondary small columns, specifically including:

[0014] Each column, large and small, contains sloping wing structures on both sides, a parabolic top, and a central core trunk;

[0015] In the simulation space, a fine spherical air structure is covered to simulate the pores in the actual preparation of the thermal barrier coating;

[0016] The geometric structural properties of the thermal barrier coating geometric model are extracted, and the structure of the thermal barrier coating geometric model is adjusted.

[0017] Further, in step 1, defining the material properties of each part includes:

[0018] The ceramic surface layer is an EB-PVD ceramic surface layer, and its geometric model material is set to 8wt% yttrium oxide-stabilized zirconium oxide; the substrate material is set to platinum aluminum metal; and the pore structure material is set to air.

[0019] Furthermore, in step 2, the boundary conditions of the FDTD simulation region include:

[0020] The periodic repeating structure in the horizontal direction is simulated by setting periodic conditions on both sides of the horizontal boundary.

[0021] PML perfectly matched layers are set on both sides of the vertical boundary to simulate the propagation space at infinity.

[0022] Furthermore, the simulation conditions settings in step 2 also include settings for simulation dimension, simulation time, mesh accuracy, simulation space size, and simulation cutoff conditions;

[0023] The simulation dimension was set to 2D, the simulation time was set to 330,000 fs, the simulation mesh was set to be divided into model regions, the wing part was divided into a 6nm cubic mesh, the rest of the structure used a system adaptive mesh, and the mesh accuracy level was set to 5.

[0024] The simulation space size is set according to the smallest unit of the thermal barrier coating, and the simulation cutoff condition is set to 1E-6.

[0025] Furthermore, in step 3, the light source is a Bloch periodic plane wave source with a wavelength set to the 1-3.5 μm band, and several points at medium frequencies are selected for spectral calculation. The monitor first uses a refractive index monitor to observe the mesh division of the model to ensure that the model is not distorted due to mesh division. Then, a frequency domain power monitor is set to monitor the electric field intensity and Poynting vector in the top region of the model to obtain the transmittance curve.

[0026] Furthermore, in step 5, the change in model structure includes:

[0027] Different thermal barrier coating thicknesses, porosities, and vertical density of the feathers were set.

[0028] In a second aspect, the present invention provides a computer device, including a memory and a processor, wherein the memory stores a computer program, and when the processor runs the computer program stored in the memory, it performs the steps of a simulation method for low infrared thermal emissivity of a turbine blade thermal barrier coating as described above.

[0029] Thirdly, the present invention provides a computer-readable storage medium storing a plurality of computer instructions, the plurality of computer instructions being used to cause a computer to execute a simulation method for the low infrared thermal emissivity of a turbine blade thermal barrier coating as described above.

[0030] Fourthly, the present invention provides an electronic device, comprising:

[0031] At least one processor; and,

[0032] A memory communicatively connected to the at least one processor; wherein,

[0033] The memory stores instructions that can be executed by the at least one processor to enable the at least one processor to perform a simulation method for the low infrared thermal emissivity of a turbine blade thermal barrier coating as described above.

[0034] The beneficial effects of this invention are:

[0035] This invention provides a simulation method for the low infrared thermal emissivity of thermal barrier coatings, overcoming the shortcomings of existing technologies and experimental measurements, and providing guidance for the subsequent preparation of thermal barrier coatings in terms of emissivity control.

[0036] This invention establishes a geometric model of EB-PVD thermal barrier coating. By setting the geometric properties of the simulation model, thermal barrier coating models with different structures are automatically generated, which can more comprehensively reflect the influence of changes in the microstructure of the thermal barrier coating on the emissivity in the low infrared band. The research results provide guidance for the subsequent preparation of thermal barrier coatings in terms of emissivity control.

[0037] This invention innovatively proposes a novel three-dimensional columnar EB-PVD coating model. This model features controllable vertical plume density and considers the contact characteristics between large and small columns of the specific structure of the inner and outer coatings. Furthermore, the emissivity predicted by this model agrees well with experimental results.

[0038] The model of this invention has been automated, and thermal barrier coatings with different microstructures can be generated simply by setting the parameters of geometric properties. This makes it easier to explore the influence of changes in the microstructure of thermal barrier coatings on the emissivity in the low infrared band. The research results provide guidance for the subsequent preparation of thermal barrier coatings in terms of emissivity control.

[0039] In summary, this invention provides a simulation method for the low infrared thermal emissivity of thermal barrier coatings, which greatly reduces the economic and time costs of experimentally measuring the emissivity of thermal barrier coatings, and has good economic benefits.

[0040] This invention is applicable to infrared thermometry, infrared stealth and protection of thermal barrier coatings and related fields. Attached Figure Description

[0041] To more clearly illustrate the technical solution of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0042] Figure 1 This is a schematic diagram of the simulation method for the low infrared thermal emissivity of the thermal barrier coating of the present invention.

[0043] Figure 2 This involves setting up the FDTD simulation scheme for the thermal barrier coating.

[0044] Figure 3 This is a schematic diagram of the 3D model of the EB-PVD thermal barrier coating.

[0045] Figure 4 This is a schematic diagram of the established microstructure of the EB-PVD thermal barrier coating;

[0046] Figure 5 The comparison of emissivity between experiments and simulations of a 200µm thick ceramic surface thermal barrier coating is presented.

[0047] Figure 6 The comparison of emissivity of thermal barrier coatings with ceramic surface thicknesses of 100µm, 200µm, 300µm and 400µm was established.

[0048] Figure 7 The comparison is between the emissivity of thermal barrier coatings with no porosity, 5% porosity, and 10% porosity.

[0049] Figure 8 The study establishes a comparison of the emissivity of three different vertically sparse thermal barrier coatings. Detailed Implementation

[0050] To more clearly illustrate the objectives, technical solutions, and advantages of this invention, the invention will be further described in detail with reference to specific embodiments and the accompanying drawings. It should be understood that the following description is merely illustrative and does not limit the scope of the invention. Descriptions of well-known structures and technologies have been omitted in the description to avoid obscuring the concepts of the invention.

[0051] Implementation Method 1: A method for simulating the low infrared thermal emissivity of a thermal barrier coating on turbine blades, the method comprising:

[0052] Step 1: Establish a geometric model and define the material properties of each part. The geometric model of the thermal barrier coating includes a ceramic surface layer and a substrate structure consisting of a trapezoidal large column and its two side secondary small columns.

[0053] Step 2: Based on the micrograph of the thermal barrier coating, set the boundary conditions of the simulation area to simulate the electromagnetic field behavior of the actual environment, and set the FDTD simulation conditions to obtain reasonable results.

[0054] Step 3: Set up the simulation light source and monitor, including: placing a plane wave above the thermal barrier coating geometry model, incident vertically; the monitor is used to obtain the transmittance curve;

[0055] Step 4: Perform simulation calculations and result analysis. By sampling the Poynting vector in the simulation area, the electromagnetic field power distribution in different frequency domains is obtained. After data processing, the emissivity data of the thermal barrier coating is obtained.

[0056] Step 5: Purposefully change the modeling structure settings to set multiple sets of simulation conditions, update the positions of the simulation light source and monitor, obtain multiple sets of emissivity data, compare and analyze the results, and provide guidance for the subsequent preparation of thermal barrier coatings in terms of emissivity control.

[0057] This embodiment provides a simulation method for the low infrared thermal emissivity of thermal barrier coatings. It can establish a geometric model of the EB-PVD thermal barrier coating, and automatically generate thermal barrier coating models with different structures by setting the geometric properties of the simulation model. This method can more comprehensively reflect the influence of changes in the microstructure of the thermal barrier coating on the low infrared emissivity. The research results provide guidance for the subsequent preparation of thermal barrier coatings in terms of emissivity control.

[0058] Implementation Method Two: This implementation method further defines the simulation method for low infrared thermal emissivity of a turbine blade thermal barrier coating described in Implementation Method One. In this implementation method, the geometric model of the thermal barrier coating, comprising a ceramic surface layer and a substrate structure consisting of a trapezoidal large column and its two side auxiliary small columns, is further defined, specifically including:

[0059] Step 1, the thermal barrier coating geometric model includes a ceramic surface layer and a substrate structure consisting of a trapezoidal large column and its two side secondary small columns, specifically including:

[0060] Each column, large and small, contains sloping wing structures on both sides, a parabolic top, and a central core trunk;

[0061] In the simulation space, a fine spherical air structure is covered to simulate the pores in the actual preparation of the thermal barrier coating;

[0062] The geometric structural properties of the thermal barrier coating geometric model are extracted, and the structure of the thermal barrier coating geometric model is adjusted.

[0063] In this embodiment, the electromagnetic field simulation software FDTD Solutions developed by Lumerical Corporation can be used for modeling. The model mainly includes an EB-PVD ceramic surface layer and substrate structure composed of a trapezoidal main column and its two smaller secondary columns. More specifically, each column includes inclined wing structures on both sides, a parabolic top, and a central core. Simultaneously, tiny spherical air structures are overlaid in the simulation space to simulate the porosity in the actual fabrication of the thermal barrier coating. Typical geometric properties are extracted from the established geometric model, including porosity, wing horizontal tilt angle (theta), wing vertical density, ceramic coating thickness (H), main column length (L), and main column width (W). These parameters are used to flexibly control the model structure; that is, by changing these geometric properties, the structure of the thermal barrier coating can be freely altered to generate thermal barrier coating models with different microstructures. This allows for the exploration of the regulatory effect of different thermal barrier coating microstructures on emissivity.

[0064] This embodiment proposes a novel three-dimensional columnar EB-PVD coating model. This model features controllable vertical feather density and considers the contact characteristics between the large and small columns of the inner and outer coatings. Furthermore, the emissivity predicted by this model agrees well with the experimental results.

[0065] Implementation Method 3 further defines the simulation method for low infrared thermal emissivity of turbine blade thermal barrier coatings described in Implementation Method 2. In this implementation method, step 1, defining the material properties of each component, is further defined, specifically including:

[0066] Step 1, defining the material properties of each part includes:

[0067] The ceramic surface layer is an EB-PVD ceramic surface layer, and its geometric model material is set to 8wt% yttrium oxide-stabilized zirconium oxide; the substrate material is set to platinum aluminum metal; and the pore structure material is set to air.

[0068] This embodiment presents the material properties of each part of the thermal barrier coating geometric model.

[0069] Implementation Method Four: This implementation method further defines the simulation method for low infrared thermal emissivity of turbine blade thermal barrier coatings described in Implementation Method One. In this implementation method, the boundary conditions of the FDTD simulation region in step 2 are further defined, specifically including:

[0070] In step 2, the boundary conditions of the FDTD simulation region include:

[0071] The periodic repeating structure in the horizontal direction is simulated by setting periodic conditions on both sides of the horizontal boundary.

[0072] PML perfectly matched layers are set on both sides of the vertical boundary to simulate the propagation space at infinity.

[0073] There are two types of boundary conditions for the simulation region in this implementation method:

[0074] One approach is the Periodic boundary condition, used to simulate periodic structures. This represents a structure with alternating large and small columns in the horizontal direction. To minimize simulation time, half of the secondary column is modeled using Periodic boundary conditions to create a complete secondary column structure. This involves uniformly halving the secondary column horizontally and then using Periodic boundary conditions to assemble it into a complete structure, forming a periodically alternating structure of large and small columns. The half-modeling is due to the Periodic boundary condition. If both sides were Periodic boundary conditions, to ensure an alternating structure of large and small columns, the secondary column should be uniformly halved horizontally and automatically assembled into a complete secondary column using Periodic boundary conditions. See details... Figure 2 .

[0075] Another type is the PML perfectly matched layer, which simulates wave propagation near the medium boundary and is an efficient absorbing boundary condition. By setting PML boundary conditions on both sides in the vertical direction, it simulates propagation space to infinity.

[0076] In this embodiment, since the established thermal barrier coating model is the smallest unit of the actual thermal barrier coating, it is necessary to combine FDTD simulation boundary conditions to obtain a realistic environment simulation.

[0077] Implementation Method Five: This implementation method further defines the simulation method for low infrared thermal emissivity of turbine blade thermal barrier coatings described in Implementation Method One. In this implementation method, the simulation conditions in step 2 are further defined, specifically including:

[0078] Step 2 also includes setting the simulation conditions, such as simulation dimension, simulation time, mesh accuracy, simulation space size, and simulation cutoff conditions.

[0079] The simulation dimension was set to 2D, the simulation time was set to 330,000 fs, the simulation mesh was set to be divided into model regions, the wing part was divided into a 6nm cubic mesh, the rest of the structure used a system adaptive mesh, and the mesh accuracy level was set to 5.

[0080] The simulation space size is set according to the smallest unit of the thermal barrier coating, and the simulation cutoff condition is set to 1E-6.

[0081] In this embodiment, the wing part is divided into a 6nm cubic grid, and the rest of the structure adopts a system adaptive grid. The grid accuracy level is set to 5 because the wing part has a fine structure and requires a finer grid structure. The simulation cutoff condition is set to 1E-6 to indicate that the electromagnetic field intensity in the region is reduced to within 1E-6, and the simulation results tend to be stable.

[0082] Implementation method six is ​​a further limitation on the simulation method for low infrared thermal emissivity of turbine blade thermal barrier coatings described in implementation method one. In this implementation method, the simulation light source in step 3 is further limited, specifically including:

[0083] In step 3, the light source is a Bloch periodic plane wave source with a wavelength set to the 1–3.5 μm band. 500 points at a mid-frequency range are selected for spectral calculation. The monitor first uses a refractive index monitor to observe the mesh division of the model to ensure that the model is not distorted due to mesh division. Then, a frequency domain power monitor is set to monitor the electric field intensity and Poynting vector in the x, y, and z directions of the top region of the model to obtain the transmittance curve.

[0084] In this embodiment, the monitor first uses a refractive index monitor to observe the mesh division of the model, in order to ensure that the model is not distorted due to mesh division.

[0085] Implementation method seven is a further limitation on the simulation method for low infrared thermal emissivity of turbine blade thermal barrier coatings described in implementation method one. In this implementation method, the change of model structure in step 5 is further limited, specifically including:

[0086] In step 5, the change in model structure includes:

[0087] Different thermal barrier coating thicknesses, porosities, and vertical density of the feathers were set.

[0088] In this embodiment, multiple simulation conditions were purposefully set by changing the modeling structure, including simulations of different thermal barrier coating thicknesses. Simulations were conducted using ceramic surface layer models with thicknesses of 100µm, 200µm, 300µm, and 400µm to study the effect of thermal barrier coating thickness on its low-infrared emissivity. Simulations were also conducted using different porosities of the thermal barrier coating, with models showing 5%, 10%, and no porosity to study the effect of porosity on its low-infrared emissivity. Finally, simulations were conducted using different density levels of the feathers in the vertical direction, with three models showing uniform feather arrangement, denser feather spacing from top to bottom, and sparser feather spacing from top to bottom to study the effect of feather density on the low-infrared emissivity of the thermal barrier coating. The data were processed and analyzed to provide guidance for subsequent thermal barrier coating fabrication and emissivity control.

[0089] The model in this embodiment has been automated, and thermal barrier coatings with different microstructures can be generated simply by setting the parameters of geometric properties. This makes it easier to explore the effect of changes in the microstructure of thermal barrier coatings on the emissivity in the low infrared band. The research results provide guidance for the subsequent preparation of thermal barrier coatings in terms of emissivity control.

[0090] Implementation method eight is an embodiment of a simulation method for the low infrared thermal emissivity of a turbine blade thermal barrier coating as described above, specifically including:

[0091] like Figure 1 As shown, this embodiment provides a simulation of the infrared thermal emissivity of an EB-PVD thermal barrier coating, including the following steps:

[0092] Step 1: Establish the geometric model of the EB-PVD thermal barrier coating.

[0093] A complete thermal barrier coating structure comprises a ceramic coating with low thermal conductivity and high strain compliance, a metal bonding layer that adheres the ceramic surface layer to the metal substrate, and a TGO layer composed of high-temperature, high-pressure oxidation products. The operating environment of turbine blade thermal barrier coatings includes high-temperature combustion gas environments and cooling air environments. Thermal barrier coatings are designed to reduce blade surface temperature and provide thermal insulation protection.

[0094] Step two, as Figure 2 The diagram shows a schematic of the FDTD simulation setup for the thermal barrier coating. Since the established thermal barrier coating model is the smallest unit of the actual thermal barrier coating, it needs to be combined with FDTD simulation boundary conditions to obtain a realistic environmental simulation. Periodic conditions are set on both sides of the x-direction boundary to simulate the periodic repetition of the structure in the x-direction. Perfectly matched PML layers are set on both sides of the y-direction boundary to simulate the propagation space at infinity.

[0095] Step 3: A Bloch periodic plane wave is incident vertically above the thermal barrier coating geometry model. The excitation light source wavelength ranges from 1 to 3.5 μm, and 500 points at equal frequency intervals are selected as the simulation light source input. Two frequency domain power monitors are set up to monitor the electric field intensity and Poynting vector in the x, y, and z directions.

[0096] Step four: When the electric field strength within the simulation area is below 1E-6, the simulation stops, signifying its completion. Transmittance curves are obtained by viewing two frequency domain power monitors, yielding reflectivity and transmittance. Based on Kirchhoff's laws, the emissivity data of the thermal barrier coating is then obtained, as shown in Table 1.

[0097] Table 1 FDTD Simulation Setup Scheme

[0098]

[0099] Step 5: Establish multiple sets of comparative simulation conditions to explore the effects of different thicknesses of the thermal barrier coating on infrared emissivity, different porosities of the thermal barrier coating on infrared emissivity, and different vertical feather densities of the thermal barrier coating on infrared emissivity, and provide guidance for subsequent preparation of thermal barrier coatings in terms of emissivity control.

[0100] like Figure 3 The diagram illustrates the core geometric modeling of the infrared thermal emissivity simulation of the EB-PVD thermal barrier coating of this invention. Research shows that the ceramic layer can be divided into an inner coating region and an outer coating region. In the inner coating region, the columnar structures are interdependent and in contact, resulting in a denser structure. In the outer coating region, the column heads have a coarse-grained structure with obvious gaps between the columns, and the coating exhibits a feather-like microstructure. Therefore, the geometric modeling of the EB-PVD thermal barrier coating of this invention mainly consists of a large trapezoidal column and its two smaller secondary columns, with the structure periodically extended in the x-direction.

[0101] like Figure 4 The diagram shown is a schematic representation of the microstructure of the EB-PVD thermal barrier coating. The construction of this geometric model is described in detail from the perspective of various geometric properties.

[0102] The described wing structure consists of N minimum wing units on one side, each of which is formed by superimposing and rotating a cuboid structure and a semi-cylindrical structure. In the scripting language, this is described as: `addrect` adds a cuboid structure, `addring` adds a ring structure, sets the structure size and position, and adjusts the `rotation` axis to achieve the horizontal tilt of the minimum wing unit.

[0103] Generating a single-sided wing structure from the smallest wing unit requires iterative traversal in both the horizontal and vertical directions.

[0104] In the horizontal direction, through the horizontal center x of the smallest unit of the bottommost wing 01 and the horizontal center x of the smallest unit of the topmost wing 02 Determine the maximum horizontal distance, denoted as X. max X max Divide by the number of wings N to obtain the horizontal spacing of each wing in the horizontal direction.

[0105] In the vertical direction, this modeling emphasizes the variation in vertical gap between wings, defining a wing vertical density (Density) to control the wing vertical gap offset, while also considering the maximum limit range of the wing gap.

[0106] Calculations show that when Density is set to -1, the vertical gap of the uppermost feathers is squeezed to 0, and as the thickness increases, the feather gap increases at a rate proportional to the offset.

[0107] Calculations show that when Density is set to 0, it indicates that the vertical gaps between the wings are evenly arranged.

[0108] Calculations show that when Density is set to 1, the vertical gap of the bottommost feathers is squeezed to 0, and as the thickness decreases, the feather gap increases at a rate proportional to the offset.

[0109] Of course, any value of Density within [-1, 1] represents different vertical gaps between wings. If the value exceeds this range, it will cause an extreme situation, that is, the wings will overlap.

[0110] The parabolic top structure is generated by importing a custom geometry structure using the addcustom command, determining the coordinate points of the parabolic top shape, and then using the stretch and rotate commands. Additionally, a central torso structure and a base structure are added.

[0111] In summary, a complete thermal barrier coating structure can be generated and managed uniformly under a single Structure Group.

[0112] Furthermore, the material configuration of the thermal barrier coating structure. The ceramic surface layer uses 8wt% yttrium-stabilized zirconium oxide (8YSZ). A document named Wood_1_3.5.txt is prepared, formatted in three columns: the first column defines the frequency band, the second column defines the real part of the 8YSZ refractive index, and the third column defines the imaginary part of the 8YSZ refractive index.

[0113] In FDTD Solutions, import the Wood_1_3.5.txt document and add the 8YSZ material properties.

[0114] The Material Explorer toolkit is used to fit material parameters and set the material properties for each part of the generated model.

[0115] Additionally, the Air_gaps.lsf script file was written to add a porous structure, which uniformly distributes tiny spherical structures in space, and the material property is defined as air to simulate the porous structure.

[0116] Define the porosity variable as the proportion of the volume occupied by the air structure to the total space. Considering that the generated spherical structures will overlap, the generated porosity will be slightly less than the set porosity. Therefore, the pre-generated air structure is appropriately increased to meet the requirements. Save the file as Air_gaps.lsf.

[0117] Import the Air_gaps.lsf file into the FDTD Solutions software, run the script to generate air_gaps structure groups, and freely adjust the porosity of the structure.

[0118] In FDTDAnalysis, user-defined attributes of the generated structure are extracted from the model, such as ceramic coating thickness H, trapezoidal column length L, column width W, vertical density of the plumes (Density), porosity, and plume tilt angle α. Specifically, the parameter settings for a thermal barrier coating with a ceramic coating thickness of 200 μm are shown in Table 2 below.

[0119] Table 2. Parameter settings for thermal barrier coatings with a ceramic coating thickness of 200 μm

[0120] The length of the main column is L (um). ～4.8 Large pillar W(um) ～4.8 Vertical density of feathers [-1～1] Wing tilt angle α (°) 45 Porosity 10%, 5%, etc.

[0121] like Figure 5 As shown in the experimental and simulation results of the 200µm ceramic surface layer, the simulation of the infrared thermal emissivity of the EB-PVD thermal barrier coating of the present invention is within a certain error range. The simulation results and experimental results have good consistency in the range of emissivity values ​​and variations, further confirming the reliability of the simulation method.

[0122] like Figure 6 As shown, the effect of different thermal barrier coating thicknesses on emissivity was simulated. The results indicate that, except for some overlap in emissivity at lower wavelengths, the emissivity of the thermal barrier coating increases monotonically with increasing thickness.

[0123] The commonly used method in industry to adjust the thickness of ceramic surface layer is to use appropriate process parameters and control conditions, such as controlling electron beam power and substrate rotation speed, to adjust the thickness of ceramic surface layer.

[0124] like Figure 7As shown, the effect of different thermal barrier coating porosities on emissivity was simulated. The results indicate that the effect of different porosities is more pronounced in the lower wavelength range. Increased porosity amplifies the backscattering of the thermal barrier coating, which enhances its reflectivity. According to Kirchhoff's law, the spectral emissivity decreases with increasing porosity.

[0125] like Figure 8 As shown, the effect of different vertical sparse densities of feathers on emissivity was simulated. The results indicate that in the 1–3.5 μm band, the emissivity of the uniform feather sparse density model is greater than that of the sparse density model with sparse upper and dense lower feathers, which in turn is greater than that of the sparse density model with dense upper and sparse lower feathers.

[0126] The density of the plumes can be controlled by adjusting the deposition rate and temperature, providing guidance for the subsequent preparation of thermal barrier coatings in terms of emissivity regulation.

[0127] In summary, this invention provides a simulation method for the infrared thermal emissivity of EB-PVD thermal barrier coatings. This method can accurately simulate the emissivity of thermal barrier coatings under complex environments and can generate different thermal barrier coating models by flexibly changing model parameters to simulate the influence of microstructure parameters of thermal barrier coatings on emissivity. This greatly reduces the measurement cost of studying thermal barrier coatings under high temperature and high pressure service environments, and has good economic benefits.

[0128] It should be understood that the specific embodiments of the present invention described above are merely illustrative or explanatory of the construction concept of the present invention and should not be construed as limiting the present invention. Therefore, any modifications, equivalent substitutions, improvements, etc., made without departing from the spirit and scope of the present invention should be included within the protection scope of the present invention. Furthermore, the appended claims are intended to cover all variations and modifications falling within the scope and boundaries of the appended claims, or equivalent forms of such scope and boundaries.

Claims

1. A method for simulating the low infrared thermal emissivity of a thermal barrier coating on turbine blades, characterized in that, The method includes: Step 1: Establish the geometric model of the thermal barrier coating and define the material properties of each part; The thermal barrier coating geometric model includes a ceramic surface layer and a substrate structure consisting of a trapezoidal large column and two secondary small columns on its sides; Step 2: Based on the micrograph of the thermal barrier coating, set the boundary conditions of the simulation area to simulate the electromagnetic field behavior of the actual environment, and at the same time set the FDTD simulation conditions; Step 3: Set up the simulation light source and monitor, including: placing a plane wave above the thermal barrier coating geometry model, incident vertically; the monitor is used to obtain the transmittance curve; Step 4: Perform simulation calculations and result analysis. By sampling the Poynting vector in the simulation area, the electromagnetic field power distribution in different frequency domains is obtained, and then the emissivity data of the thermal barrier coating is obtained. Step 5: By changing the model structure, set multiple sets of simulation conditions, update the positions of the simulation light source and monitor, and obtain multiple sets of emissivity data.

2. The method for simulating the low infrared thermal emissivity of a turbine blade thermal barrier coating according to claim 1, characterized in that, Step 1, the thermal barrier coating geometric model includes a ceramic surface layer and a substrate structure consisting of a trapezoidal large column and its two side secondary small columns, specifically including: Each column, large and small, contains sloping wing structures on both sides, a parabolic top, and a central core trunk; In the simulation space, a fine spherical air structure is covered to simulate the pores in the actual preparation of the thermal barrier coating; The geometric structural properties of the thermal barrier coating geometric model are extracted, and the structure of the thermal barrier coating geometric model is adjusted.

3. The method for simulating the low infrared thermal emissivity of a turbine blade thermal barrier coating according to claim 2, characterized in that, Step 1, defining the material properties of each part includes: The ceramic surface layer is an EB-PVD ceramic surface layer, and its geometric model material is set to 8wt% yttrium oxide-stabilized zirconium oxide; the substrate material is set to platinum aluminum metal; and the pore structure material is set to air.

4. The method for simulating the low infrared thermal emissivity of a turbine blade thermal barrier coating according to claim 1, characterized in that, In step 2, the boundary conditions of the FDTD simulation region include: The periodic repeating structure in the horizontal direction is simulated by setting periodic conditions on both sides of the horizontal boundary. PML perfectly matched layers are set on both sides of the vertical boundary to simulate the propagation space at infinity.

5. The method for simulating the low infrared thermal emissivity of a turbine blade thermal barrier coating according to claim 1, characterized in that, Step 2 also includes setting the simulation conditions, such as simulation dimension, simulation time, mesh accuracy, simulation space size, and simulation cutoff conditions. The simulation dimension was set to 2D, the simulation time was set to 330,000 fs, the simulation mesh was set to be divided into model regions, the wing part was divided into a 6nm cubic mesh, the rest of the structure used a system adaptive mesh, and the mesh accuracy level was set to 5. The simulation space size is set according to the smallest unit of the thermal barrier coating, and the simulation cutoff condition is set to 1E-6.

6. The method for simulating the low infrared thermal emissivity of a turbine blade thermal barrier coating according to claim 1, characterized in that, In step 3, the light source is a Bloch periodic plane wave source with a wavelength set to the 1-3.5 μm band. Several points at medium frequencies are selected for spectral calculation. The monitor first uses a refractive index monitor to observe the mesh division of the model to ensure that the model is not distorted due to mesh division. Then, a frequency domain power monitor is set to monitor the electric field intensity and Poynting vector in the top region of the model to obtain the transmittance curve.

7. The method for simulating the low infrared thermal emissivity of a turbine blade thermal barrier coating according to claim 1, characterized in that, In step 5, the change in model structure includes: Different thermal barrier coating thicknesses, porosities, and vertical density of the feathers were set.

8. A computer device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that, The steps of the method according to any one of claims 1 to 7 are performed when the processor runs the computer program stored in the memory.

9. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a plurality of computer instructions, which are used to cause a computer to perform the method of any one of claims 1 to 7.

10. An electronic device, characterized in that, include: At least one processor; as well as, A memory communicatively connected to the at least one processor; wherein, The memory stores instructions that can be executed by the at least one processor to enable the at least one processor to perform the method of any one of claims 1 to 7.

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