Turbine cooling blade and corrosion protection coating design method thereof

Abstract

The invention provides a turbine cooling blade and a corrosion protection coating design method thereof, and relates to the technical field of gas turbines.The turbine cooling blade corrosion protection coating design method comprises the steps that a turbine cooling blade coating test piece is constructed, a corrosion protection coating is sprayed to the surface of the test piece, a corrosion test is conducted, and the relation between the thickness corrosion rate of the corrosion protection coating and temperature and time is obtained; different temperature areas on the surface of the turbine cooling blade are partitioned, the average temperature of all the temperature areas is obtained, and the corrosion rate of the corrosion protection coating of all the temperature areas at the average temperature is determined; the service life of the turbine cooling blade is determined, and the corrosion protection coating thickness of each temperature area is determined; and the thickness values of the corrosion protection coatings in all the temperature areas are overlapped with the original outer molded surface of the turbine cooling blade to obtain a new outer molded surface of the turbine cooling blade, the new outer molded surface of the turbine cooling blade is subjected to fairing treatment, and the difference between the fairing new outer molded surface of the turbine cooling blade and the original outer molded surface of the turbine cooling blade is the thickness distribution of the corrosion protection coatings.

Description

Technical Field

[0001] This application belongs to the technical field of gas turbines, and particularly relates to a turbine cooling blade and a design method for its corrosion protection coating. Background Technique

[0002] Aero-engines and marine gas turbines are used in the marine environment for a long time. The environmental conditions of high temperature, high humidity, and high salt fog further exacerbate the corrosion and oxidation rates of the matrix of turbine cooling blades, reducing the reliability of turbine cooling blades and shortening the service life of turbine cooling blades.

[0003] In order to improve the corrosion resistance of turbine cooling blades, a corrosion protection coating is usually coated on the surface of turbine cooling blades to protect the matrix of turbine cooling blades from corrosion. The thickness of the corrosion protection coating is an important factor affecting the corrosion resistance of turbine cooling blades. Since the shape of the turbine cooling blade itself is a three-dimensional curved surface and the temperatures endured by different parts of the surface of the turbine cooling blade are different, the required coating thicknesses at different positions on the surface of the turbine cooling blade are different.

[0004] In the prior art, after the structural design of the turbine cooling blade is completed, in order to achieve the overall protection effect, a corrosion protection coating with a constant thickness is generally pre-coated on the outer surface of the turbine cooling blade, and then the thickness is adjusted by adapting to the blade structure and coating spraying technology to complete the design of the corrosion protection coating of the turbine cooling blade. However, for the corrosion protection coating designed by this method, the differences in the corrosion resistance requirements of different regions of the blade are not considered, and problems such as excessive margin or insufficient protection are likely to occur. Summary of the Invention

[0005] The purpose of this application is to provide a turbine cooling blade and a design method for its corrosion protection coating to solve or alleviate at least one problem in the background technique.

[0006] In a first aspect, the technical solution of this application is: a design method for a corrosion protection coating of a turbine cooling blade, characterized by including:

[0007] S10, constructing a coating test piece of a turbine cooling blade, spraying a corrosion protection coating on the surface of the test piece, and conducting a corrosion test on the test piece sprayed with the corrosion protection coating to obtain the relationship between the thickness corrosion rate of the corrosion protection coating and temperature and time;

[0008] S20, partitioning different temperature regions on the surface of the turbine cooling blade, obtaining the average temperature of each temperature region, and determining the thickness corrosion rate of the corrosion protection coating in each temperature region at the average temperature according to the average temperature;

[0009] S30. Determine the service life of the turbine cooling blade, and determine the thickness of the corrosion protection coating for each temperature region according to the service life.

[0010] S40. Superimpose the thickness values of the corrosion protection coatings for each temperature region on the original outer profile surface of the turbine cooling blade to obtain a new outer profile surface of the turbine cooling blade. Smooth the new outer profile surface of the turbine cooling blade. The difference between the smoothed new profile surface of the turbine cooling blade and the original outer profile surface of the turbine cooling blade is the thickness distribution of the corrosion protection coating.

[0011] Preferably, in step S10, the specific process of obtaining the relationship between the thickness corrosion rate of the corrosion protection coating and temperature and time includes:

[0012] Detect the thickness of the corrosion protection coating before and after the test for each test piece to obtain the coating thickness δ q before the test and the coating thickness δ h after the test, and calculate the thickness corrosion rate where t is the test time;

[0013] By setting different test temperatures T and test times t, form a test matrix of test temperature T and test time t and the thickness corrosion rate α;

[0014] Based on the test matrix, obtain the relationship between the thickness corrosion rate α and the test temperature T and test time t, that is, α = f(T, t), where f(T, t) is the relationship obtained according to the test matrix.

[0015] Preferably, the test temperature T covers the service temperature range of the turbine cooling blade, and the test time t is greater than the service life requirement of the turbine cooling blade.

[0016] Preferably, in step S20, the process of determining the thickness corrosion rate of the corrosion protection coating at the current average temperature of each temperature region includes:

[0017] Divide the surface temperature distribution of the turbine cooling blade into m temperature regions, and obtain the average temperature T bw (Di) of the i-th temperature region through numerical calculation or experimental test of the temperature field of the turbine cooling blade;

[0018] According to the average temperature of the i-th temperature region and the relationship between the thickness corrosion rate α of the corrosion protection coating and temperature T and time t, obtain the thickness corrosion rate of the corrosion protection coating at the current average temperature of this temperature region: α(Di) = f i (t);

[0019] where α(Di) is the thickness corrosion rate of the corrosion protection coating at the current average temperature of the i-th temperature region;

[0020] f i(t) is the relationship obtained by substituting the current average temperature into the function relationship f(T, t).

[0021] Preferably, the thickness δ(Di) of the corrosion protection coating in each of the temperature regions satisfies:

[0022]

[0023] In the formula, δ(Di) is the thickness of the corrosion protection coating in the i-th temperature region;

[0024] t0 is the service life requirement of the turbine cooling blade.

[0025] Preferably, the minimum coating thickness in each temperature region after fairing is greater than the thickness of the corrosion protection coating in the corresponding temperature region.

[0026] On the other hand, the present application provides a turbine cooling blade, on the surface of which a corrosion protection coating is provided, and the corrosion protection coating is designed according to any one of the above-mentioned turbine cooling blade corrosion protection coating design methods.

[0027] The turbine cooling blade corrosion protection coating design method provided by the present application starts from the anti-corrosion performance requirements of the turbine cooling blade. Compared with the existing turbine cooling blade corrosion protection coating which is applied under the design requirement of a constant thickness value, the corrosion protection coating of the present application is a variable-thickness corrosion protection coating design for the entire blade body, which can adapt to the complex external shape structure of the turbine cooling blade, and overcome the problem that when a constant thickness coating is used for a turbine cooling blade with a complex shape, the corrosion protection coating does not fully match the local anti-corrosion requirements due to uneven coating thickness, resulting in the anti-corrosion performance not meeting the design requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions provided by the present application, the drawings will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application.

[0029] Figure 1 It is a schematic diagram of the turbine cooling blade corrosion protection coating design method of the present application.

[0030] Figure 2 It is a schematic diagram of each region in an embodiment of the present application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0031] In order to make the purpose, technical solutions and advantages of the implementation of the present application clearer, the technical solutions in the embodiments of the present application will be described in more detail below with reference to the drawings in the embodiments of the present application.

[0032] In view of the fact that the thickness of the corrosion protection coating in the prior art cannot meet the anti-corrosion requirements of different regions of the blade and cannot adapt to the external shape structure of the blade to ensure that the blade matrix is not corroded, the present application provides a turbine cooling blade and a design method for its corrosion protection coating.

[0033] As Figure 1 shown, the design method for the corrosion protection coating of the turbine cooling blade proposed in the present application includes the following process:

[0034] S10. Construct a test piece of the turbine cooling blade coating, spray a corrosion protection coating on the surface of the test piece, and conduct a corrosion test on the test piece sprayed with the corrosion protection coating, so as to obtain the relationship between the thickness corrosion rate α of the corrosion protection coating and the temperature T and time t.

[0035] In the present application, the test piece is a test piece with the same matrix material as the turbine cooling blade matrix. The corrosion protection coating on the surface of the test piece is coated by spraying the corrosion protection coating on the surface of the test piece. When conducting the corrosion test, the test piece sprayed with the corrosion protection coating is placed in an environment of a specific corrosion medium to achieve the corrosion test.

[0036] The process of obtaining the relationship between the thickness corrosion rate α of the corrosion protection coating and the temperature T and time t in the present application includes:

[0037] S11. Detect the thickness of the corrosion protection coating on each test piece before and after the test, and record them as the coating thickness δ q before the test and the coating thickness δ h after the test respectively. The thickness corrosion rate α is calculated according to the following formula:

[0038]

[0039] S12. By setting different test temperatures T and test times t, form a test matrix of the test temperature T and test time t and the thickness corrosion rate α, as shown in Table 1.

[0040] Table 1 Test matrix

[0041] t1 t2 … tm T1 α(T1, t1) α(T1, t2) … α(T1, tm) T2 α(T2, t1) α(T2, t2) … α(T2, tm) … … … … … Tn α(Tn, t1) α(Tn, t2) … α(Tn, tm)

[0042] S13. Based on the obtained test matrix, the relationship between the thickness corrosion rate α and the test temperature T and test time t can be obtained, that is, α = f(T, t), where f(T, t) is the relational expression obtained according to the test matrix.

[0043] In the preferred embodiment of the present application, the test temperature T in the above test process needs to cover the service temperature range of the designed turbine cooling blade, and the test time t in the test process needs to be greater than the design life requirement of the turbine cooling blade. The intervals of the test temperature T and test time t can be reasonably selected according to actual needs.

[0044] S20. Partition different temperature regions on the surface of the turbine cooling blade, obtain the average temperature of each temperature region, and determine the corrosion rate of the corrosion protection coating in each temperature region at the average temperature according to the average temperature of each temperature region of the turbine cooling blade and the relationship between the corrosion rate α of the corrosion protection coating thickness obtained in step S10 and temperature T and time t.

[0045] As shown in Fig. 2, it is a schematic diagram of the temperature distribution on the turbine cooling blade in an embodiment of the present application. In the present application, the surface temperature distribution of the turbine cooling blade is divided into m temperature regions. The number and position of the temperature regions are determined according to the turbine cooling blade to be designed. For the temperature of each temperature region Di (i = 1, 2,..., m), the average temperature T bw (Di) of this temperature region can be obtained through the turbine cooling blade simulation model or the temperature field numerical calculation method.

[0046] In the present application, the corrosion rate α(Di) of the corrosion protection coating in each temperature region at the average temperature satisfies: α(Di) = f i (t), where f i (t) is the relational expression obtained by substituting the current average temperature according to the f(T, t) functional relational expression.

[0047] S30. Determine the service life of the turbine cooling blade, and determine the thickness of the corrosion protection coating in this temperature region according to the service life of the turbine cooling blade and the corrosion rate of the corrosion protection coating in the current average temperature of the temperature region obtained in step S20.

[0048] In the present application, the thickness δ(Di) of the corrosion protection coating in this temperature region satisfies:

[0049]

[0050] where t0 is the service life requirement of the turbine cooling blade.

[0051] S40. Superimpose the obtained thickness values δ(Di) of the corrosion protection coating in each temperature region on the original external surface F of the turbine cooling blade, so as to obtain a new external surface F' of the turbine cooling blade, and perform fairing treatment on the external surface F' of the turbine cooling blade. The difference between the fairing external surface F' of the turbine cooling blade and the original external surface F of the turbine cooling blade is the thickness distribution of the corrosion protection coating.

[0052] In the present application, the minimum coating thickness value δ min (Di) in each temperature region Di after fairing needs to be greater than the thickness δ(Di) of the corrosion protection coating in the corresponding temperature region, that is, δ min (Di) ≥ δ(Di).

[0053] In some embodiments of the present application, the fairing method can be selected according to actual needs. For example, a surface fairing method based on curvature can be adopted, or a global / local optimization method can be adopted. After fairing, the new outer surface F' of the turbine cooling blade needs to reach G 2 continuous, where G 2 Continuous means that the surface is point-to-point continuous, and the result of its curvature analysis is continuously changing.

[0054] Based on this technology, the present application also provides a turbine cooling blade, and the surface of the turbine cooling blade is provided with a corrosion protection coating, and the corrosion protection coating is designed according to the above method.

[0055] The design method of the corrosion protection coating for the turbine cooling blade provided by the present application starts from the anti-corrosion performance requirements of the turbine cooling blade. Compared with the corrosion protection coating of the turbine cooling blade in the prior art, which is coated under the design requirement of a constant thickness value, the corrosion protection coating of the present application is a corrosion protection coating design with variable thickness along the entire blade body, which can adapt to the complex outer shape structure of the turbine cooling blade, and overcome the problem that when a constant thickness coating is used for a turbine cooling blade with a complex shape, the corrosion protection coating does not fully match the local anti-corrosion requirements due to uneven coating thickness, resulting in the anti-corrosion performance not meeting the design requirements.

[0056] The above is only the specific implementation manner 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 those skilled in the art within the technical scope disclosed in the present application should be covered by the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claimed rights.

Claims

1. A design method for corrosion protection coating of a turbine cooling blade, characterized in that, Including: S10. Construct a test piece of the turbine cooling blade coating, spray a corrosion protection coating on the surface of the test piece, conduct a corrosion test on the test piece with the sprayed corrosion protection coating, and obtain the relationship between the thickness corrosion rate of the corrosion protection coating and temperature and time; S20. Divide different temperature regions on the surface of the turbine cooling blade, obtain the average temperature of each temperature region, and determine the thickness corrosion rate of the corrosion protection coating in each temperature region at the average temperature; S30. Determine the service life of the turbine cooling blade, and determine the thickness of the corrosion protection coating in each temperature region according to the service life; S40. Superimpose the thickness values of the corrosion protection coatings in each temperature region on the original external profile of the turbine cooling blade to obtain a new external profile of the turbine cooling blade, perform fairing on the new external profile of the turbine cooling blade, and the difference between the fairing-processed new profile of the turbine cooling blade and the original external profile of the turbine cooling blade is the thickness distribution of the corrosion protection coating.

2. The corrosion protection coating design method for the turbine cooling blade according to claim 1, characterized in that, In step S10, the specific process of obtaining the relationship between the thickness corrosion rate of the corrosion protection coating and temperature and time includes: Detect the thickness of the corrosion protection coating before and after the test for each test piece to obtain the coating thickness δ before the test q and the coating thickness δ after the test h , and calculate the thickness corrosion rate where t is the test time; By setting different test temperatures T and test times t, form a test matrix of test temperature T, test time t, and thickness corrosion rate α; Based on the test matrix, obtain the relationship between the thickness corrosion rate α and the test temperature T and test time t, that is, α = f(T, t), where f(T, t) is the relationship obtained according to the test matrix.

3. The corrosion protection coating design method for a turbine cooling blade according to claim 2, characterized in that, The test temperature T covers the service temperature range of the turbine cooling blade, and the test time t is greater than the service life requirement of the turbine cooling blade.

4. The corrosion protection coating design method for a turbine cooling blade according to claim 3, characterized in that, In step S20, the process of determining the thickness corrosion rate of the corrosion protection coating at the current average temperature of each temperature region includes: Divide the surface temperature distribution of the turbine cooling blade into m temperature regions, and obtain the average temperature T(Di) of the i-th temperature region through numerical calculation or experimental test of the temperature field of the turbine cooling blade. bw (Di); According to the average temperature of the i-th temperature region and the thickness corrosion rate α of the corrosion protection coating, the relationship between the corrosion rate α and the temperature T and time t is used to obtain the thickness corrosion rate of the corrosion protection coating at the current average temperature of this temperature region: α(Di) = f i (t); In the formula, α(Di) is the thickness corrosion rate of the corrosion protection coating at the current average temperature of the i-th temperature region; f i (t) is the relationship obtained by substituting the current average temperature into the function relation f(T, t).

5. The corrosion protection coating design method for a turbine cooling blade according to claim 4, characterized in that The thickness δ(Di) of the corrosion protection coating in each of the temperature regions satisfies: In the formula, δ(Di) is the thickness of the corrosion protection coating in the i-th temperature region; t0 is the service life requirement of the turbine cooling blade.

6. The corrosion protection coating design method for a turbine cooling blade according to claim 1, characterized in that The minimum coating thickness in each temperature region after fairing is greater than the thickness of the corrosion protection coating in the corresponding temperature region.

7. A turbine cooling blade, characterized in that, The surface of the turbine cooling blade is provided with a corrosion protection coating, and the corrosion protection coating is designed according to the turbine cooling blade corrosion protection coating design method described in any one of claims 1 to 6.

Images