A simulation method for the influence of hot corrosion and ablation on the performance of a gas turbine turbine
By reconstructing the ablation blade model using reverse engineering and CFD simulation, the scientific assessment challenge of thermal corrosion and ablation effects on gas turbine blades was solved, enabling accurate simulation of turbine performance and damage assessment, and providing design and maintenance guidance.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2023-02-03
- Publication Date
- 2026-04-07
AI Technical Summary
Existing technologies lack scientific data references and cannot effectively assess and prevent the effects of thermal corrosion and ablation on gas turbine blades, leading to a reduction in turbine efficiency and power.
采用逆向造型和CFD仿真方法，通过扫描仪重建烧蚀叶片模型，提取损伤值，划分网格，设置边界条件，模拟叶片粗糙度和燃气物性，计算流场数据，建立不同工况下的数据库。
Accurately measure turbine blade damage at low cost, provide design and maintenance guidance, improve the accuracy of turbine performance prediction, and reduce experimental requirements.
Smart Images
Figure CN115952686B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the technical field of a simulation method for gas turbine performance, specifically to a simulation method for the effects of thermal corrosion and ablation on gas turbine performance. Background Technology
[0002] Marine gas turbines, like aircraft engines during takeoff, landing, and low-altitude flight, inevitably ingest salty air. When gas turbines operate in the highly salty marine environment for extended periods, corrosive molten salts adhere to the surfaces of blades, hubs, and casings, accelerating the oxidation process—a phenomenon known as thermal corrosion. As turbine inlet temperatures increase, gas turbine output power and thermodynamic cycle efficiency also improve. Advanced engines, aiming for high thrust-to-weight ratios and overall efficiency, continuously raise turbine inlet temperatures. However, impurities in the fuel and air, or abnormal airflow structures, can lead to uneven temperature distribution at the turbine inlet, even generating hot spots where the highest temperature is approximately twice the lowest. These localized overheating zones on the turbine blades subject them to immense thermal stress. Prolonged exposure to these hot spots inevitably results in turbine ablation.
[0003] Ablation and thermal corrosion alter the surface structure of turbine blades, thereby changing the inlet angle, increasing leakage flow, increasing turbulence, and worsening internal turbine flow, ultimately reducing turbine efficiency and power. In summary, the impact of ablation and thermal corrosion on turbine blades is particularly significant. Currently, there is no data to provide reference suggestions for the research, development, maintenance, and repair of turbine blades; everything relies on experience. Therefore, more scientific data is needed for reference to improve the overall development of the industry.
[0004] To address the aforementioned issues, a series of improvements were made. Summary of the Invention
[0005] The purpose of this invention is to provide a simulation method for the effects of thermal corrosion and ablation on the performance of gas turbines, so as to overcome the shortcomings and deficiencies of the existing technology.
[0006] A simulation method for the effects of thermal corrosion and ablation on gas turbine performance includes the following steps:
[0007] Step 1: Use a scanner to reverse engineer the solid model of the ablated gas turbine. Then, use digitization, CAD model creation and data application to replicate the model. Use a laser non-contact handheld 3D scanner to scan the ablated blades and correct the scanned data to complete the model reconstruction.
[0008] Step 2: Extract the profile lines at different blade heights after ablation, and measure the indentation distance at the leading edge of the profile lines at different blade heights. This is used as the blade damage value caused by ablation at the leading edge of the blade. The distance between the profile lines and the straight line at the top and root of the blade is 0 mm. Fit the measured blade damage values to obtain the damage value curve at different relative blade heights in a dimensionless coordinate system. This curve is used as the damage caused by ablation to the leading edge of the blade.
[0009] Step 3: Mesh the turbine flow domain. Modify the original model file based on the damage values calculated in Step 2, and mesh the file. Calculate the height of the first mesh layer based on the turbulence model and the y+ value.
[0010] Step 4: Extract the surface roughness of the blade after thermal corrosion, measure the roughness of the pressure surface and suction surface of the blade, draw a scatter plot of roughness value versus chord length, fit the scatter plot to obtain a fitting curve, and obtain a series of scatter points based on the fitting curve.
[0011] Step 5: Import the mesh from Step 3 into the CFD system and set the boundary conditions. Set the inlet to total pressure inlet P1 and the outlet to static pressure outlet P2. Set the wall surface to a rough wall surface without slippage. Set the roughness fitting curve and write the scatter points obtained in Step 4 into the fitting curve module to simulate the roughness of the real blade. Set the rotational speed for each stage of the moving blade.
[0012] Step 6: Customize the physical property parameters of the gas and set the physical property fitting curve of the gas. In the parameters of the fitting curve, Cp is the specific heat and t is the gas temperature.
[0013] Step 7: Calculate the flow field and obtain the flow field data.
[0014] Furthermore, in step one, the reverse modeling refers to the process of copying a model when there are no drawings or model design parameters. This includes obtaining a digital CAD model and some data application modules based on the physical object. The reverse modeling operation process includes data measurement, data processing, model building, and data application. The data measurement involves measuring the model surface using a scanning device to obtain the basic data of the model. The data processing involves removing error points caused by environmental factors during the scanning process and correcting the measurement data after obtaining the scanned data. The model building involves reconstructing a three-dimensional model based on the processed data. The data application involves repairing and redesigning the model according to requirements after the model building is completed.
[0015] Furthermore, in step two, for the blade model, before ablation, its leading edge is a straight line. Connecting two points at the blade tip and the blade root, a leading edge straight line is drawn. Using this straight line as the normal, planes are drawn at different blade heights (5% apart) to intersect the blade, obtaining the intersection line between the plane and the blade. The leading edge profile is measured and extracted. The distance between the leading edge of the profile at different blade heights and the straight line is measured and used as the blade damage value caused by ablation at the blade leading edge. The distance between the profile at the blade tip and the straight line at the blade root is 0 mm. The measured blade damage value is fitted to obtain the damage value curve at different relative blade heights in a dimensionless coordinate system. This curve is used as the loss caused by ablation to the blade leading edge. The cross-sectional line is exported in the form of a point set. The original model file is modified according to the obtained point set and imported into Autogrid5 / IGG for mesh generation.
[0016] Furthermore, for blades with different degrees of ablation, blade models with different degrees of ablation are obtained through steps one and two. Then, by modifying the coordinate values, model files under different degrees of ablation are obtained, which can be used as materials to study the influence of different degrees of ablation on turbine performance.
[0017] Furthermore, in step four, a polynomial fitting is used to obtain a fitting curve to ensure the accuracy of the fitting; after obtaining the fitting curve, 3600 points are uniformly selected within the chord length interval to describe the fluctuation of the curve.
[0018] Furthermore, in step five, the roughness value is the coordinate value with respect to the chord length direction and the rotation axis direction. The Z-axis is selected as the rotation axis, so the roughness value is a function of the Z-axis coordinate. Ks represents the fitted curve of the roughness, so the custom form should be Ks(Z). Then, the scattered points obtained in step four are written into Ks(Z).
[0019] Furthermore, in step six, in the gas property fitting curve Cp(t), Cp is the specific heat and t is the gas temperature. The temperature range is selected as 100K~2000K according to the working temperature of the turbine blades, with 100K intervals. Within this temperature range, 20 specific heat values are input. During the calculation process, the specific heat value at the current temperature will be obtained from the fitting curve of the input points and will be included in the calculation.
[0020] Furthermore, under different degrees of thermal corrosion and ablation, the changes in turbine efficiency, turbine power, total temperature ratio, expansion ratio, and flow turbine performance parameters under different operating conditions were calculated by changing the outlet back pressure. The influence of thermal corrosion and ablation on turbine performance under different operating conditions was investigated, and a database of aerodynamic parameters under different degrees of thermal corrosion, ablation, and operating conditions was established.
[0021] The beneficial effects of this invention are:
[0022] After accurately measuring the roughness value, this invention can explore the impact of different degrees of hot corrosion on turbine performance based on different roughness values. Without the need for experimental preparation, a database can be obtained at low cost, providing guidance for the design, protection, and maintenance of turbine blades. Attached Figure Description
[0023] Figure 1. A three-dimensional model of the first two stages of a turbine used in this invention.
[0024] Figure 2 This is a flowchart of the reverse engineering process for step one of the present invention.
[0025] Figure 3 This is a schematic diagram of blade ablation data extraction.
[0026] Figure 4 This is a schematic diagram of the ablation section of the mesh.
[0027] Figure 5 Curves showing the relationship between different roughness values and chord length. Detailed Implementation
[0028] The present invention will be further described below with reference to specific embodiments. These embodiments are for illustrative purposes only and are not intended to limit the scope of the invention.
[0029] Example 1
[0030] Figure 1. A three-dimensional model of the first two stages of a turbine used in this invention. Figure 2 This is a flowchart of the reverse engineering process for step one of the present invention. Figure 3 This is a schematic diagram of blade ablation data extraction. Figure 4 This is a schematic diagram of the ablation section of the mesh. Figure 5 Curves showing the relationship between different roughness values and chord length.
[0031] A simulation method for the effects of thermal corrosion and ablation on gas turbine performance includes the following steps:
[0032] Step 1: Use a scanner to reverse engineer the solid model of the ablated gas turbine. Then, use digitization, CAD model creation and data application to replicate the model. Use a laser non-contact handheld 3D scanner to scan the ablated blades and correct the scanned data to complete the model reconstruction.
[0033] Step 2: Extract the profile lines at different blade heights after ablation, and measure the indentation distance at the leading edge of the profile lines at different blade heights. This is used as the blade damage value caused by ablation at the leading edge of the blade. The distance between the profile lines and the straight line at the top and root of the blade is 0 mm. Fit the measured blade damage values to obtain the damage value curve at different relative blade heights in a dimensionless coordinate system. This curve is used as the damage caused by ablation to the leading edge of the blade.
[0034] Step 3: Mesh the turbine flow domain. Modify the original model file based on the damage values calculated in Step 2, and mesh the file. Calculate the height of the first mesh layer based on the turbulence model and the y+ value.
[0035] Step 4: Extract the surface roughness of the blade after thermal corrosion, measure the roughness of the pressure surface and suction surface of the blade, draw a scatter plot of roughness value versus chord length, fit the scatter plot to obtain a fitting curve, and obtain a series of scatter points based on the fitting curve.
[0036] Step 5: Import the mesh from Step 3 into the CFD system and set the boundary conditions. Set the inlet to total pressure inlet P1 and the outlet to static pressure outlet P2. Set the wall surface to a rough wall surface without slippage. Set the roughness fitting curve and write the scatter points obtained in Step 4 into the fitting curve module to simulate the roughness of the real blade. Set the rotational speed for each stage of the moving blade.
[0037] Step 6: Customize the physical property parameters of the gas and set the physical property fitting curve of the gas. In the parameters of the fitting curve, Cp is the specific heat and t is the gas temperature.
[0038] Step 7: Calculate the flow field and obtain the flow field data.
[0039] like Figure 1 and 2 As shown, this patent uses a real turbine blade that has undergone thermal corrosion and ablation, and employs reverse engineering to capture the shape of the ablated blade, extracting the profile at the ablation location, and then modifying the original model. The entire process balances the requirements of numerical simulation while maximizing the reproduction of the ablated blade model. In step one, reverse engineering refers to the process of replicating the model when there are no drawings or model design parameters. This includes obtaining a digital CAD model and some data application modules based on the physical object. The reverse engineering operation process includes: data measurement, data processing, model building, and data application. Data measurement involves measuring the model surface using a scanning device to obtain the basic data of the model. Data processing involves removing error points caused by environmental factors during the scanning process and correcting the measurement data after obtaining the scanned data. Model building involves reconstructing a three-dimensional model based on the processed data. Data application involves repairing and redesigning the model according to requirements after the model building is completed.
[0040] like Figure 3 As shown, in step two, for the blade model, before ablation, its leading edge is a straight line. Connecting the two points at the blade tip and the blade root, a leading edge straight line is drawn. Using this straight line as the normal, planes are drawn at different blade heights at intervals of 5% to intersect the blade, obtaining the intersection line between the plane and the blade. The leading edge profile is measured and extracted. The distance between the leading edge of the profile at different blade heights and the straight line is measured and used as the blade damage value caused by ablation at the blade leading edge. The distance between the profile at the blade tip and the straight line at the blade root is 0 mm. The measured blade damage value is fitted to obtain the damage value curve at different relative blade heights in a dimensionless coordinate system. This curve is used as the loss caused by ablation to the blade leading edge. The cross-sectional line is exported in the form of a point set. The original model file is modified according to the obtained point set and imported into Autogrid5 / IGG for mesh generation.
[0041] For blades with different degrees of ablation, blade models with different degrees of ablation are obtained through steps one and two. Then, by modifying the coordinate values, model files under different degrees of ablation are obtained, which can be used as materials to study the impact of different degrees of ablation on turbine performance.
[0042] In step four, a polynomial fitting is used to obtain the fitting curve to ensure the accuracy of the fitting. After obtaining the fitting curve, 3600 points are uniformly selected within the chord length interval to describe the fluctuation of the curve.
[0043] In step five, the roughness value is the coordinate value with respect to the chord length direction and the rotation axis direction. The Z-axis is selected as the rotation axis, so the roughness value is a function of the Z-axis coordinate. Ks represents the fitted curve of the roughness, so the custom form should be Ks(Z). Then, the scattered points obtained in step four are written into Ks(Z).
[0044] In step six, in the physical property fitting curve Cp(t) of the gas, Cp is the specific heat and t is the gas temperature. The temperature range of 100K~2000K is selected according to the working temperature of the turbine blades, with 100K as the interval. 20 specific heat values are input in this temperature range. During the calculation process, the specific heat value at the current temperature will be obtained from the fitting curve of the input points and participate in the calculation.
[0045] Under different degrees of thermal corrosion and ablation, the changes in turbine efficiency, turbine power, total temperature ratio, expansion ratio, and flow rate turbine performance parameters under different operating conditions are calculated by changing the outlet back pressure. The influence of thermal corrosion and ablation on turbine performance under different operating conditions is investigated, and a database of aerodynamic parameters under different degrees of thermal corrosion, ablation, and operating conditions is established.
[0046] The research environment of this invention is the effects of thermal corrosion and ablation under marine salt spray. These are not two different topics, because ablation and thermal corrosion occur simultaneously in gas turbines during long-term operation. There will not be a situation where only ablation occurs without thermal corrosion. Therefore, to study ablation, thermal corrosion must be taken into account. The two are an integral whole.
[0047] The core innovation of this invention lies in steps one and two, specifically the extraction of the profile lines of the ablated portion of the blade during reverse shaping. The calculation formula utilizes existing technology, while the selection of the calculation method and parameters are also innovative aspects of this invention.
[0048] In this implementation, a scanner was first used to reverse engineer the ablated gas turbine turbine solid model. Reverse engineering is the process of replicating a model when drawings and model design parameters are lacking. The reverse engineering flowchart is shown below, which divides reverse engineering into three parts: digitization, CAD modeling, and data application. The reverse engineering used in this paper involves obtaining a 3D model from the physical object, namely, digitization, CAD modeling, and some data application modules. According to the reverse engineering operation flow, it can be divided into data measurement, data processing, model building, and data application. Data measurement involves measuring the model surface using scanning equipment to obtain the model's basic data. Data processing involves removing error points caused by environmental factors during the scanning process and correcting the measurement data after obtaining the scanned data. Model building involves reconstructing the 3D model based on the processed data. Data application involves repairing and redesigning the model according to requirements after model building is completed. In summary, through step one, we restored the original blade model, that is, the complete model without ablation, in GeoMturbo format for subsequent digitization processing.
[0049] In step two, the blade profiles at different heights after ablation are extracted, and the indentation distance at the leading edge of the profiles at different heights is measured. This distance is used as the blade damage value caused by ablation at the leading edge. Specifically, I measure the indentation distance at the leading edge of the profiles at different heights to represent the blade damage value caused by ablation at the leading edge. Because the leading edge of the blade is no longer complete after damage occurs, it exhibits a phenomenon similar to chipping. What I need to do is measure the volume of the chipped material and then modify the points at the leading edge position in the GeoMurbo file of the complete blade model to simulate the damage. Figure 4As shown, in step three, the turbine flow domain is meshed. In this embodiment, we can use the autogrid5 function in Numeca software to read the original geomturbo format model file from step one. This file is essentially the blade profile at different blade heights. Autogrid5 can obtain the blade model based on this profile, similar to the lofting function in SolidWorks. This file can be opened with Notepad, meaning I can write the ablation points obtained into this file, modify the profile of the original file, generate a new geomturbo file, and then import it into Autogrid5, thus obtaining the ablated blade model. This invention meshes the blade simply by modifying point coordinates, changing the profile, and changing the blade model.
[0050] Thus, we have addressed the core of this simulation method: restoring the initial model and adding damage values to it, thereby digitally modeling a gas turbine turbine affected by thermal corrosion and ablation. The software in this embodiment is merely a convenient tool; replacing it with other types of tools would not affect its computational effectiveness. Therefore, the core of this invention is not the functionality of these software programs.
[0051] like Figure 5As shown, starting from step four, it is necessary to extract the surface roughness of the blade after thermal corrosion, measure the roughness of the pressure and suction surfaces of the blade, plot a scatter plot of roughness values versus chord length, fit the scatter plot to obtain a fitted curve, and obtain a series of scatter points based on the fitted curve. A polynomial fitting is used to obtain the fitted curve to ensure fitting accuracy; after obtaining the fitted curve, 3600 points are uniformly selected within the chord length interval to describe the fluctuation of the curve. Next, in step five, the mesh from step three is imported into the CFD system and boundary conditions are set. The inlet is set to total pressure inlet P1 and the outlet is set to static pressure outlet P2. The wall is set to a rough wall without slippage. A roughness fitting curve is set and the scattered points obtained in step four are written into the fitting curve module to simulate the roughness of the real blade. The rotational speed is set for each stage of the moving blade. The roughness value is the coordinate value with respect to the chord length direction and the rotation axis direction. The Z-axis is selected as the rotation axis. Therefore, the roughness value is a function of the Z-axis coordinate. Ks represents the roughness fitting curve. Therefore, the custom form should be Ks(Z). The scattered points obtained in step four are then written into Ks(Z). In step six, the physical property parameters of the gas are customized, and a fitting curve for the gas properties is set. In the parameters of the fitting curve, Cp represents specific heat and t represents the gas temperature. In the gas property fitting curve Cp(t), Cp represents specific heat and t represents the gas temperature. Based on the operating temperature of the turbine blades, a temperature range of 100K~2000K is selected, with 100K intervals. Twenty specific heat values are input within this temperature range. During the calculation, the specific heat value at the current temperature is obtained from the fitting curve based on the input points and participates in the calculation. This step mainly involves calculating the impact of changing variables on the model, thereby establishing a database. Specifically, in step five, in the ANSYS CFX module, a curve can be manually provided in the wall roughness settings of the boundary conditions. The roughness varies according to the value of this curve. This line is obtained by measuring the actual blade roughness and obtaining a series of scattered points, then fitting a polynomial. After fitting, a series of points are taken from this fitted curve and written into the CFX module. The CFX module will then perform fitting based on the input points.
[0052] Similarly, in step six, by modifying the physical property parameters, specifically by outputting a series of points, the cfx module fits a curve based on the input points: the physical property fitting curve Cp(t) of the gas.
[0053] Specifically, in this embodiment, we add a new material to the cfx module and name it HPT GAS. Then, we import a series of points into the system, where the horizontal axis represents temperature and the vertical axis represents specific heat. The cfx module will then fit a curve based on this series of points and participate in the calculation to obtain a set of analytical expressions, which are named Cp(T), where Cp is the function value and T is the independent variable. This function is then brought into the system's specific heat capacity calculation module, thus completing the definition of the physical property parameters.
[0054] Therefore, the entire calculation process is actually implemented through a system, which does not necessarily require a specific software. The same functionality is not only found in existing technologies but is also a commonly used tool in this field. Therefore, the calculation process is not the innovative point of this invention.
[0055] Finally, in step seven, the flow field is calculated and flow field data is obtained. Under different degrees of thermal corrosion and ablation, the turbine efficiency, turbine power, total temperature ratio, expansion ratio and flow rate turbine performance parameters under different operating conditions can be calculated by changing the outlet back pressure. This allows us to explore the influence of thermal corrosion and ablation on the turbine under different operating conditions and to establish a database of aerodynamic parameters under different degrees of thermal corrosion, ablation and operating conditions.
[0056] In summary, reverse engineering has wide applications in the field of engineering technology, and its principle is not a new concept. However, its application in the study of turbine blade ablation is rare. Currently, there is no content in this field to guide the research of this invention. Therefore, the application of this technology is a completely new technical feature with significant creativity. There is limited research on turbine blade ablation and thermal corrosion both domestically and internationally, especially on ablation itself. This patent combines the combined effects of thermal corrosion and ablation to deeply explore the impact of their coupled effects on turbine aerodynamic performance, providing a novel method for subsequent research.
[0057] The beneficial effects of this invention are as follows: Since turbines of shipborne aircraft and marine gas turbines are highly susceptible to ablation and thermal corrosion in marine salt spray environments, leading to a sharp decline in turbine performance, studying the impact of ablation and thermal corrosion on turbines aims to obtain, through simulation, the deterioration law of turbine performance under different damage degrees (thermal corrosion degree / ablation degree). This is why I mentioned the establishment of a database in the last claim, because parameters such as power and efficiency are all part of the characterization of turbine performance. This invention simulates different operating conditions by changing the back pressure at the outlet, thus obtaining the turbine performance under different operating conditions with the same damage degree. Furthermore, through data processing, it can determine which has a greater impact under different operating conditions: thermal corrosion or ablation. This has guiding significance for the design, protection, and maintenance of turbine blades.
[0058] The specific embodiments of the present invention have been described above, but the present invention is not limited thereto. Various changes can be made to the present invention as long as they do not depart from the spirit of the present invention.
Claims
1. A simulation method for the effects of thermal corrosion and ablation on gas turbine performance, characterized in that, Includes the following steps: Step 1: Use a scanner to reverse engineer the solid model of the ablated gas turbine. Then, use digitization, CAD model creation and data application to replicate the model. Use a laser non-contact handheld 3D scanner to scan the ablated blades and correct the scanned data to complete the model reconstruction. Step 2: Extract the profile lines at different blade heights after ablation, and measure the indentation distance at the leading edge of the profile lines at different blade heights. This is used as the blade damage value caused by ablation at the leading edge of the blade. The distance between the profile lines and the straight line at the top and root of the blade is 0 mm. Fit the measured blade damage values to obtain the damage value curve at different relative blade heights in a dimensionless coordinate system. This curve is used as the damage caused by ablation to the leading edge of the blade. Step 3: Mesh the turbine flow domain. Modify the original model file based on the damage values calculated in Step 2, and mesh the file. Calculate the height of the first mesh layer based on the turbulence model and the y+ value. Step 4: Extract the surface roughness of the blade after thermal corrosion, measure the roughness of the pressure surface and suction surface of the blade, draw a scatter plot of roughness value versus chord length, fit the scatter plot to obtain a fitting curve, and obtain a series of scatter points based on the fitting curve. Step 5: Import the mesh from Step 3 into the CFD system and set the boundary conditions. Set the inlet to total pressure inlet P1 and the outlet to static pressure outlet P2. Set the wall surface to a rough wall surface without slippage. Set the roughness fitting curve and write the scatter points obtained in Step 4 into the fitting curve module to simulate the roughness of the real blade. Set the rotational speed for each stage of the moving blades; Step 6: Customize the physical property parameters of the gas and set the physical property fitting curve of the gas. In the parameters of the fitting curve, Cp is the specific heat and t is the gas temperature. Step 7: Calculate the flow field and obtain the flow field data.
2. The simulation method for the effects of thermal corrosion and ablation on gas turbine performance according to claim 1, characterized in that: In step one, reverse modeling refers to the process of copying a model when there are no drawings or model design parameters. It includes obtaining a digital CAD model and some data application modules based on the physical object. The reverse modeling operation process includes data measurement, data processing, model building, and data application. Data measurement is to measure the surface of the model using a scanning device to obtain the basic data of the model. Data processing is to remove error points caused by environmental factors during the scanning process and correct the measurement data after obtaining the scanned data. Model building is to reconstruct a three-dimensional model based on the processed data. Data application is to repair and redesign the model according to the requirements after the model building is completed.
3. The simulation method for the effects of hot corrosion and ablation on gas turbine performance according to claim 1, characterized in that: In step two, for the blade model, before ablation, its leading edge is a straight line. Connecting the two points at the blade tip and the blade root, a leading edge straight line is drawn. Using this straight line as the normal, planes are drawn at different blade heights (5% apart) to intersect the blade, obtaining the intersection line between the plane and the blade. The leading edge profile is measured and extracted. The distance between the leading edge of the profile at different blade heights and the straight line is measured and used as the blade damage value caused by ablation at the blade leading edge. The distance between the profile at the blade tip and the straight line at the blade root is 0 mm. The measured blade damage value is fitted to obtain the damage value curve at different relative blade heights in a dimensionless coordinate system. This curve is used as the loss caused by ablation to the blade leading edge. The cross-sectional line is exported in the form of a point set. The original model file is modified according to the obtained point set and imported into Autogrid5 / IGG for mesh generation.
4. The simulation method for the effects of hot corrosion and ablation on gas turbine performance according to claim 1, characterized in that: For blades with different degrees of ablation, blade models with different degrees of ablation are obtained through steps one and two. Then, by modifying the coordinate values, model files under different degrees of ablation are obtained, which can be used as materials to study the impact of different degrees of ablation on turbine performance.
5. The simulation method for the effects of hot corrosion and ablation on gas turbine performance according to claim 1, characterized in that: In step four, a polynomial fitting is used to obtain a fitting curve to ensure the accuracy of the fitting. After obtaining the fitting curve, 3600 points are uniformly selected within the chord length interval to describe the fluctuation of the curve.
6. The simulation method for the effects of hot corrosion and ablation on gas turbine performance according to claim 1, characterized in that: In step five, the roughness value is the coordinate value with respect to the chord length direction and the rotation axis direction. The Z-axis is selected as the rotation axis, so the roughness value is a function of the Z-axis coordinate. Ks represents the fitted curve of the roughness, so the custom form should be Ks(Z). Then, the scattered points obtained in step four are written into Ks(Z).
7. The simulation method for the effects of thermal corrosion and ablation on gas turbine performance according to claim 1, characterized in that: In step six, in the physical property fitting curve Cp(t) of the gas, Cp is the specific heat and t is the gas temperature. The temperature range is selected as 100K~2000K according to the working temperature of the turbine blade, with 100K as the interval. Within this temperature range, 20 specific heat values are input. During the calculation process, the specific heat value at the current temperature will be obtained from the fitting curve of the input points and participate in the calculation.
8. The simulation method for the effects of hot corrosion and ablation on gas turbine performance according to claim 1, characterized in that: Under different degrees of thermal corrosion and ablation, the changes in turbine efficiency, turbine power, total temperature ratio, expansion ratio, and flow rate turbine performance parameters under different operating conditions are calculated by changing the outlet back pressure. The influence of thermal corrosion and ablation on turbine performance under different operating conditions is investigated, and a database of aerodynamic parameters under different degrees of thermal corrosion, ablation, and operating conditions is established.