Geometric parameter optimization design method for turbine blade film hole with low cooling efficiency and attenuation

Abstract

The invention discloses a cooling efficiency low-attenuation turbine blade film hole geometric parameter optimization design method, and belongs to the field of gas engine turbine blades, and the method comprises the following steps: counting blade data, and establishing a film hole geometric characteristic parameter corresponding relation of a blade design state and an attenuation state based on the blade data; a center composite test table is designed based on the corresponding relation of the geometrical characteristic parameters of the film holes and the researched parameter change range; constructing a simulation model based on the central composite test table and calculating to obtain a simulation result; and performing parameter optimization based on a simulation result to obtain an optimal geometric parameter of the film hole. According to the method, the influence of geometric characteristic deviation of the blade on the cooling effect in the manufacturing, coating spraying and service environments is comprehensively considered, the blade is correspondingly optimized and improved from the initial stage of design, it is guaranteed that the blade cooling effect is not sensitive to parameter changes in the wide working range, and the ablation risk of the blade is effectively reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of gas engine turbine blades, and in particular relates to a method for optimizing geometrical parameters of air film holes of turbine blades with low cooling efficiency and attenuation. Background Art

[0002] In order to meet the performance requirements of higher thrust-to-weight ratio of aircraft engines, the temperature of the gas before the turbine continues to increase, and the blades are subjected to extremely high heat loads, and it is urgent to arrange effective film cooling on the blade surface for thermal protection.

[0003] At present, the optimization goal of the optimal layout of the geometric characteristic parameters of the blade film hole is often to achieve better coverage and cooling performance. Domestic and foreign researchers have conducted a lot of research on this goal. However, in the processing and manufacturing of blades, there are inevitably aperture deviations, position deviations, inclination deviations, etc.; when applying the coating, different differences will occur due to different sequences. For example, drilling first and then spraying the coating often leads to local blockage of the film hole, and spraying the coating first and then drilling often leads to curling of the coating at the hole mouth, and even the risk of coating shedding; after the blade has been in service for a period of time, the morphology near the hole mouth may change due to the deposition of carbon black particles that are not fully burned in the inhaled sand or high-temperature combustion gas. The above phenomena will cause the cooling effect of the blade in actual work to be lower than the original design state expectation, and it is difficult to support the long-term reliable operation of the blade. Therefore, it is necessary to consider the impact of the above phenomena in the early design, take the blade design cooling effect and cooling effect attenuation as the comprehensive optimization goals, balance the constraint relationship between the two, and support the further optimization design of the low-attenuation film hole structure of the blade. Summary of the invention

[0004] In order to solve the above technical problems, the present invention proposes a method for optimizing the geometric parameters of air film holes of turbine blades with low cooling efficiency and attenuation, so as to solve the problems existing in the above prior art.

[0005] To achieve the above object, the present invention provides a method for optimizing the geometric parameters of film holes of turbine blades with low cooling efficiency and attenuation, comprising:

[0006] Collecting blade data and establishing a corresponding relationship between geometric characteristic parameters of air film holes in blade design state and attenuation state based on the blade data;

[0007] Designing a central composite test table based on the corresponding relationship between the geometric characteristic parameters of the air film hole and the parameter variation range studied;

[0008] Building a simulation model based on the central composite test table and calculating the simulation results;

[0009] Based on the simulation results, parameter optimization is performed to obtain the optimal air film hole geometric parameters.

[0010] Optionally, the process of establishing the corresponding relationship between the geometric characteristic parameters of the air film holes in the blade design state and the attenuation state includes:

[0011] Statistical analysis of the parameter frequencies of the geometric characteristic parameters of the air film holes at each stage;

[0012] Obtaining the parameter variation rules of each stage based on the parameter frequency;

[0013] Based on the parameter variation rules of each stage, the influence of the processing deviation of each parameter, coating spraying and service environment on the deviation of the air film hole diameter is analyzed to obtain the single factor influence rules of each stage;

[0014] The functional relationship of the single factor influence rules of each stage is connected in series to obtain the corresponding relationship between the geometric characteristic parameters of the air film holes in the blade design state and the attenuation state.

[0015] Optionally, the geometric characteristic parameters of the air film hole include the air film hole diameter, flow direction inclination angle, and span direction inclination angle.

[0016] Optionally, the process of designing a central composite test table includes:

[0017] Determine typical factors based on the single factor influence rules;

[0018] Determining a variation range corresponding to the selected parameter based on the typical factors;

[0019] A central composite test table is designed based on the variation range corresponding to the selected parameters.

[0020] Optionally, the central composite test table includes design points, axis points, and star points.

[0021] Optionally, the process of constructing a simulation model based on the central composite test table and calculating includes:

[0022] preparing a corresponding turbine blade geometry model for each set of parameter combinations based on the central composite test table;

[0023] Meshing each turbine blade geometry model to generate computational mesh for numerical simulation;

[0024] Set boundary conditions;

[0025] Performing numerical simulation calculations based on the boundary conditions and the computing network to obtain the cooling efficiency performance of the blade under different parameter combinations;

[0026] Based on the cooling efficiency performance of the blade under different parameter combinations, key results are collected and correlation fitting is performed to obtain a cooling efficiency correlation formula.

[0027] Optionally, the process of performing parameter optimization based on the simulation results includes: performing associative optimization on the cooling effect of the blade and the cooling effect attenuation based on processing accuracy, selected parameters, a variation range corresponding to the selected parameters and optimization accuracy.

[0028] Optionally, after obtaining the optimal air film hole geometric parameters, the method further includes a process of modeling and performing simulation verification based on the optimal air film hole geometric parameters.

[0029] Compared with the prior art, the present invention has the following advantages and technical effects:

[0030] The present invention addresses the key issue that the cooling efficiency of turbine blades does not meet expectations during use, explores the key influencing factors that lead to this phenomenon, comprehensively considers the influence of geometric feature deviations of blades in manufacturing, coating spraying and service environment on the cooling efficiency, and optimizes and improves the blades accordingly from the initial design stage to ensure that the cooling efficiency of the blades is insensitive to parameter changes in a wide working range, effectively reducing the risk of blade ablation, and has a relatively broad application prospect. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The drawings constituting a part of the present application are used to provide a further understanding of the present application. The illustrative embodiments and descriptions of the present application are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0032] Figure 1 It is a flow chart of a method for optimizing geometric parameters of film holes of a turbine blade with low cooling efficiency and attenuation according to an embodiment of the present invention;

[0033] Figure 2 A schematic diagram of a three-dimensional model of a high-pressure turbine rotor blade according to an embodiment of the present invention;

[0034] Figure 3 This is a schematic diagram of the distribution of air film holes of a moving blade according to an embodiment of the present invention;

[0035] Figure 4 A curve chart showing the statistics of machining deviations of geometric features of air film holes according to an embodiment of the present invention;

[0036] Figure 5 A curve chart showing the statistical degree of air film pore blocking caused by coating spraying according to an embodiment of the present invention;

[0037] Figure 6 A curve chart showing the statistical deviation of the air film hole diameters of the blades according to the embodiment of the present invention after a period of service;

[0038] Figure 7 1 is a corresponding diagram of geometric characteristic parameters of the designed blade and the attenuated blade according to an embodiment of the present invention. DETAILED DESCRIPTION

[0039] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0040] It should be noted that the steps shown in the flowcharts of the accompanying drawings can be executed in a computer system such as a set of computer executable instructions, and that, although a logical order is shown in the flowcharts, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0041] Embodiment 1

[0042] The present invention aims to address the deficiencies in the prior art and proposes a method for optimizing the geometric parameters of air film holes in turbine blades with low cooling efficiency and attenuation. The method can, under the premise of relatively little calculation, comprehensively consider the effects of geometric feature deviations of blades in manufacturing, coating spraying and service environments, accurately predict the cooling efficiency attenuation and optimize the layout in a targeted manner from the front end of the design, effectively solve the problem of the cooling efficiency of the blades not meeting expectations during actual use, reduce the risk of ablation occurring during the operation of the blades, and improve the cooling margin of the blades.

[0043] like Figure 1 As shown, this embodiment provides a method for optimizing the geometric parameters of the air film holes of turbine blades with low cooling efficiency and attenuation, which is further described by taking the optimization design of the air film holes at the leading edge of the high-pressure turbine rotor blade as an example. Figure 2-Figure 3 As shown, the following steps are included:

[0044] Step 1: Based on data statistics, the corresponding relationship between the geometric characteristic parameters of the air film holes in the blade design state and the attenuation state is established, which is specifically divided into the following steps:

[0045] Step 1-1: Based on the statistical analysis of the parameters of the air film hole diameter, flow direction inclination angle, and span direction inclination angle at each stage, the parameter variation law of each stage is obtained, such as Figure 4 As shown, the analysis shows that the processing deviation of each parameter is an absolute deviation, such as Figure 5 The coatings shown are sprayed and Figure 6 The service environment has a certain functional relationship with the deviation of the air film hole diameter.

[0046] Step 1-2: Connect each stage in series, give the geometric characteristic parameter values ​​of the design state, and obtain the parameter values ​​of the final attenuation state of the blade through the regular analysis of the three stages of processing deviation, coating spraying and service. Through the correlation fitting, the one-to-one correspondence between the geometric characteristic parameters of the air film holes in the blade design stage and the corresponding parameters under the final service period (i.e., the geometric parameter attenuation law) is finally established, such as Figure 7 shown.

[0047] Step 2: Design a central composite test table based on the correspondence between the geometric characteristic parameters of the air film holes and the blade data. Select the number of research parameters and the wide parameter variation range, and design a central composite test table, which is specifically divided into the following steps: determine typical factors based on the single factor influence law; determine the variation range corresponding to the selected parameters based on the typical factors; design a central composite test table based on the variation range corresponding to the selected parameters.

[0048] Step 2-1: Based on the previous single factor influence law, a coupling influence study was conducted on typical factors, and the number of research parameters was selected. For this blade, five factors, including x1: upper end aperture deviation, x2: lower end aperture deviation, x3: acute angle flow angle deviation, x4: right angle flow angle deviation, and x5: spanwise inclination angle deviation, were selected to study the cooling effect of the leading edge film hole;

[0049] Step 2-2: According to the basic data statistics, determine the corresponding variation range of the parameters, and appropriately expand the range to support the subsequent correlation fitting under a wide parameter variation range. The parameter variation range selected for this blade is shown in Table 1:

[0050] Table 1

[0051]

[0052] Step 2-3: Design a central composite (CCD) test table, which includes design points (used for repeated tests to reduce errors), axial points (used to determine the positive and negative effects of single factors), and star points (used to measure the effects of extreme levels) to ensure a more accurate assessment of the coupling effects of multiple factors within a limited number of tests.

[0053] Step 3: Based on the central composite test table, a simulation model is constructed and numerical calculation is performed to obtain simulation results. Based on the simulation results, a correlation formula between the blade cooling effect and the cooling effect attenuation is obtained by fitting, which is specifically divided into the following steps:

[0054] Step 3-1: According to the hole diameter and hole inclination deviation values ​​at different positions of the blade in the central composite test table, parametric modeling of the leading edge hole sheet is performed in UG.

[0055] Step 3-2: Based on the Fluent meshing software, import the air film hole sheet file of each group of tests into the model mesh file without air film holes on the leading edge, execute the script file for the "Intersect" function of the mesh, realize the air film hole drilling operation of the blade, import the surface mesh and volume mesh parameters, and automatically divide the mesh of each group of test models.

[0056] Step 3-3: Perform numerical simulation calculations on each group of models in the test table, and read the local surface average temperature of the simulation results for comprehensive cooling effect and cooling effect attenuation calculation. Based on the response surface method, the cooling effect and cooling effect attenuation are expressed as a function of the superposition of quadratic terms, linear terms, and interaction terms of each factor. The simulation results are brought into the function to fit the coefficient values ​​of each function. Taking the cooling effect (φ) correlation considering five factors as an example, its expression is:

[0057]

[0058] Where a1~a 21 are the coefficient values ​​of each item, and x1~x5 are the influencing factors.

[0059] Step 4: Based on the fitted blade cooling efficiency and cooling efficiency attenuation expressions, the geometric characteristic parameters of the turbine blade with low cooling efficiency attenuation are optimized according to the required parameters and variation range. The specific steps are as follows:

[0060] Step 4-1: Optimize the parameters of the five factors x1: upper aperture deviation, x2: lower aperture deviation, x3: acute flow angle deviation, x4: right-angle flow angle deviation, and x5: spanwise inclination angle deviation. The parameters, variation range, and optimization accuracy of the given requirements are shown in Table 2.

[0061] Table 2

[0062]

[0063] Step 4-2: Optimize the correlation between the blade cooling effect and cooling effect attenuation to satisfy: Δφ B <Δφ A , and φ A ≤φ B The priority is Δφ B The smaller the better. When this condition is met, φ B The bigger the better.

[0064] Among them, Δφ A =φ A -φ A' , Δφ B =φ B -φ B' , Δφ is the cooling effect attenuation, A' and B' are the corresponding attenuation blades.

[0065] The parameter optimization results are as follows:

[0066] Parameter x1 is -0.02mm, parameter x2 is -0.04mm, parameter x3 is -15°, parameter x4 is -15°, and parameter x5 is -6°.

[0067] Step 5: Model and simulate the optimized geometric parameters of the film holes. Model the turbine blades according to the optimized geometric parameters of the film holes, and verify through numerical simulation calculations whether they meet the requirements of low cooling efficiency and attenuation. The simulation results show that the design cooling efficiency of the original blade is 0.5088, the cooling efficiency attenuation is 0.02544, and the cooling efficiency attenuation is 5%. The design cooling efficiency of the optimized blade is 0.509, the cooling efficiency attenuation is 0.01313, and the cooling efficiency attenuation is 2.58%. The cooling efficiency of the optimized blade is basically the same as that of the original blade. The cooling efficiency attenuation of the optimized blade is 48.4% lower than that of the original blade, and the cooling margin is significantly improved.

[0068] The present invention takes into account the influence of processing and manufacturing deviations, coating spraying and working environment on the cooling characteristics of the blade in the early stage of design, and realizes the optimized design of the geometric characteristic parameters of the air film holes of the turbine blade with low attenuation of cooling efficiency, which ensures that the cooling efficiency of the blade does not change significantly under the actual working environment, effectively supports the reliable operation of the blade, and has a relatively broad application prospect.

[0069] The optimization design method of the present invention comprehensively considers the influence of geometric feature deviations on the cooling efficiency of blades during manufacturing, coating spraying and service environment, accurately predicts the cooling efficiency attenuation and optimizes the layout in a targeted manner from the front end of the design, effectively solves the problem that the cooling efficiency of the blades does not meet the expectations during the actual use stage, and greatly reduces the calculation amount of blade parameter optimization.

[0070] The above are only preferred specific implementations of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A method for optimizing the geometric parameters of film holes in turbine blades with low cooling efficiency and attenuation. It is characterized in that The following steps are involved: Collecting blade data and establishing a corresponding relationship between geometric characteristic parameters of air film holes in blade design state and attenuation state based on the blade data; Designing a central composite test table based on the corresponding relationship between the geometric characteristic parameters of the air film hole and the parameter variation range studied; Building a simulation model based on the central composite test table and calculating the simulation results; Based on the simulation results, parameter optimization is performed to obtain the optimal air film hole geometric parameters.

2. The method for optimizing geometric parameters of film holes of turbine blades with low cooling efficiency and attenuation according to claim 1, It is characterized in that The process of establishing the corresponding relationship between the geometric characteristic parameters of the air film holes in the blade design state and the attenuation state includes: Statistical analysis of the parameter frequencies of the geometric characteristic parameters of the air film holes at each stage; Obtaining the parameter variation rules of each stage based on the parameter frequency; Based on the parameter variation rules of each stage, the influence of the processing deviation of each parameter, coating spraying and service environment on the deviation of the air film hole diameter is analyzed to obtain the single factor influence rules of each stage; The functional relationship of the single factor influence rules of each stage is connected in series to obtain the corresponding relationship between the geometric characteristic parameters of the air film holes in the blade design state and the attenuation state.

3. The method for optimizing geometric parameters of film holes of turbine blades with low cooling efficiency and attenuation according to claim 2, It is characterized in that The geometric characteristic parameters of the air film hole include the air film hole diameter, flow direction inclination angle, and span direction inclination angle.

4. The method for optimizing geometrical parameters of film holes of turbine blades with low cooling efficiency and attenuation according to claim 2, It is characterized in that The process of designing a central composite test table includes: Determine typical factors based on the single factor influence rules; Determining a variation range corresponding to the selected parameter based on the typical factors; A central composite test table is designed based on the variation range corresponding to the selected parameters.

5. The method for optimizing geometrical parameters of film holes of turbine blades with low cooling efficiency and attenuation according to claim 4, It is characterized in that The central composite test table includes design points, axis points, and star points.

6. The method for optimizing geometrical parameters of film holes of turbine blades with low cooling efficiency and attenuation according to claim 1, It is characterized in that The process of constructing a simulation model and calculating based on the central composite test table includes: preparing a corresponding turbine blade geometry model for each set of parameter combinations based on the central composite test table; Meshing each turbine blade geometry model to generate computational mesh for numerical simulation; Set boundary conditions; Performing numerical simulation calculations based on the boundary conditions and the computing network to obtain the cooling efficiency performance of the blade under different parameter combinations; Based on the cooling efficiency performance of the blade under different parameter combinations, key results are collected and correlation fitting is performed to obtain a cooling efficiency correlation formula.

7. The method for optimizing geometrical parameters of film holes of turbine blades with low cooling efficiency and attenuation according to claim 6, It is characterized in that The process of performing parameter optimization based on the simulation results includes: performing associative optimization on the blade cooling effect and cooling effect attenuation based on processing accuracy, selected parameters, a variation range corresponding to the selected parameters and optimization accuracy.

8. The method for optimizing geometrical parameters of film holes of turbine blades with low cooling efficiency and attenuation according to claim 7, It is characterized in that After obtaining the optimal air film hole geometric parameters, the method also includes a process of modeling and performing simulation verification based on the optimal air film hole geometric parameters.

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