A method for detecting the thermal barrier coating insulation effect

Abstract

The present application relates to the technical field of thermal protection of high-temperature components, and particularly relates to a thermal barrier coating heat insulation effect detection method, which comprises the following steps: S1, fitting the relationship between the low-temperature side temperature of a structure without a thermal barrier coating and the temperature difference between the two sides of the structure without a thermal barrier coating according to the temperatures of the high-temperature side and the low-temperature side of the structure without a thermal barrier coating at different temperatures; S2, detecting the surface temperature of a structure with a thermal barrier coating and the temperature of the low-temperature side of the substrate, and determining the temperature of the high-temperature side of the substrate of the structure with a thermal barrier coating according to the relationship between the low-temperature side temperature of the structure without a thermal barrier coating and the temperature difference between the two sides of the structure without a thermal barrier coating; and S3, obtaining the heat insulation effect of the thermal barrier coating by subtracting the temperature of the high-temperature side of the substrate from the surface temperature of the structure with a thermal barrier coating. The present application fully considers the temperature gradient of the substrate at different temperatures, increases the accuracy of the detection results, and for the same kind of substrate samples, the fitting results can be reused once calibrated, which greatly reduces the workload of the thermal barrier coating heat insulation performance test.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of thermal protection of high-temperature components, and particularly relates to a thermal barrier coating heat insulation effect detection method. BACKGROUND

[0002] With the development of aerospace and civil equipment, the temperature of the hot end of an aero-engine or a gas turbine is continuously increasing. However, the service temperature of most alloy materials is not higher than 1000 DEG C. The service temperature of alloy materials can be increased by using thermal barrier coating technology. Thermal barrier coatings (TBCs) are obtained by spraying or depositing ceramic powder on a metal surface, thereby achieving heat insulation and oxidation resistance. A classical thermal barrier coating structure is a double-layer model structure, mainly including a bond coat and a top ceramic coat. As shown in FIG. 1, the existing thermal barrier coating double-layer model structure is obtained by spraying a bond coat BC on a substrate, and the thickness of the bond coat is 100-150 μm. A ceramic layer is sprayed on the top of the bond coat, and the thickness of the ceramic layer is about 300 μm. Figure 1

[0003] Thermal insulation performance is one of the key indicators for evaluating thermal barrier coatings. The thermal insulation performance, i.e. the heat insulation effect, affects the working temperature of the component substrate and the thermal barrier coating system. In addition, the temperature in the thermal barrier coating system also indirectly affects the thermal stress of the system. Therefore, accurate evaluation of the thermal insulation performance of the thermal barrier coating not only has a very important significance for the material system design of the component, but also plays a decisive role in the engineering application, failure analysis and life assessment of the thermal barrier coating. SUMMARY

[0004] The present application aims to provide a thermal barrier coating heat insulation effect detection method with low cost and accurate measurement.

[0005] A thermal barrier coating heat insulation effect detection method, comprising the following contents:

[0006] S1, fitting the relationship between the temperature of the low-temperature side of a structure without a thermal barrier coating and the temperature difference between the two sides of the structure without a thermal barrier coating according to the temperature of the high-temperature side and the temperature of the low-temperature side of the structure without a thermal barrier coating at different temperatures;

[0007] S2, detecting the surface temperature of a thermal barrier coating structure and the temperature of the low-temperature side of a substrate, the substrate being the same as the structure without a thermal barrier coating, and determining the temperature of the high-temperature side of the substrate of the thermal barrier coating structure according to the relationship between the temperature of the low-temperature side of the structure without a thermal barrier coating and the temperature difference between the two sides of the structure without a thermal barrier coating;

[0008] S3, obtaining the heat insulation effect of the thermal barrier coating by subtracting the temperature of the high-temperature side of the substrate from the surface temperature of the thermal barrier coating structure.​

[0009] The present application has the advantages of:

[0010] The thermal barrier coating insulation effect detection method of the present application is compared with the existing method:

[0011] The embedding method has the following disadvantages: the thermocouple is relatively large in size, and it is difficult to measure the error when it is inserted into the coating; the S-type thermocouple required at high temperature is expensive; the thermocouple needs to be accurately attached to the interface between the coating and the substrate, and the operation requirement is high.

[0012] The technology disclosed in patent application No. CN201510789455.0, entitled "Interface temperature testing method for heat insulation coating test piece with embedded thermocouple", and the technology disclosed in patent application No. CN201710996855.8, entitled "Interface temperature testing method for heat insulation coating test piece", have the following disadvantages: the thinnest thermocouple on the market is 0.3 to 0.5 mm, and the thermocouple needs a protective sleeve when in use, which is relatively large in diameter and cannot measure the temperature at the interface between the thin thermal barrier coating and the substrate layer, thus cannot measure the heat insulation performance of the thin thermal barrier coating. In addition, the platinum-rhodium type thermocouple above 1600 degrees Celsius is expensive, and when the embedded thermocouple is used, the thermocouple is difficult to take out for repeated use. The embedding method is not suitable for testing thin high-temperature thermal barrier coatings.

[0013] The technology disclosed in patent application No. CN201010586727.4, entitled "Method for measuring cooling effect and heat insulation effect of turbine blade with thermal barrier coating", mainly uses the embedding thermocouple method, and the size of the thermocouple is relatively large compared with the thermal barrier coating system, so it cannot accurately measure the temperature at the interface between the substrate and the bonding layer. In addition, the patent theoretically calculates the cooling effect under the actual engine working condition, and the physical variables are not processed before calculation in the patent, and some physical variable parameters change with temperature, for example, the values of heat capacity and density at different temperatures are different, so the error between the theoretical calculation result and the actual experimental result is large.

[0014] The technology disclosed in patent application No. CN202010066299.6, entitled "Non-contact non-destructive testing method and device for heat insulation temperature of thermal barrier coating", has the following disadvantages: in this method, the infrared temperature measuring instrument is used to measure the interface between the ceramic layer and the metal bonding layer, and the infrared cannot directly penetrate the coating to measure the temperature at the interface.

[0015] Patent application number CN202110846440.9, patent name: a method for evaluating and predicting the heat insulation effect of turbine blade thermal barrier coating, in step two, based on one-dimensional coating-gas film heat transfer model, the heat flow q with thermal barrier coating and the heat flow q without thermal barrier coating are derived, there is a large error between theoretical calculation and actual experiment. And the formula disclosed in claim 6 of the patent:

[0016] ,

[0017] In the formula, the measurement of convective heat transfer coefficient h, there is no special device for measuring the convective heat transfer coefficient of thermal barrier coating cooling and heat transfer, in addition, the operation is more complex. 、 Will change based on the change of temperature, the patent does not consider With the change of temperature, and the error between the theoretical calculation and the actual situation is large.

[0018] Patent application number CN202111154914.X, patent name: a method for testing the heat insulation performance of thermal protection ceramic coating, in this method, the heat insulation capacity of the sample without coating is used to replace the heat insulation capacity of the substrate with coating, and the heat insulation capacity of the coating is calculated as the temperature difference between the high temperature side of the sample with coating and the surface temperature of the substrate. The temperature difference of the substrate surface is not considered, that is, the actual temperature reaching the substrate layer surface is lower than the temperature of the heat source without thermal barrier coating. With the same cooling effect, the temperature change of the alloy inside is shown as Figure 7 . Figure 8 The temperature difference between the two ends (x=0 and x=3) of the alloy surface is the heat insulation capacity of the substrate. It can be seen that under different substrate heat source temperatures, the temperature of the high temperature side of the substrate is different, and the heat insulation capacity of the substrate is different. Therefore, in this method, although under the same cooling effect, the heat insulation of the substrate without coating cannot be directly equivalent to the heat insulation of the substrate with coating.

[0019] The heat insulation effect detection method of the thermal barrier coating of the present application:

[0020] (1) The required equipment is simple, only the test device is needed, the temperature can be directly measured by infrared gun, without additional thermocouple, reducing the detection cost;

[0021] (2) For the same kind of substrate sample, the fitting result can be reused once calibrated, which greatly reduces the workload of thermal barrier coating heat insulation performance test;

[0022] (3) Compared with the prior art, the temperature gradient of the base at different temperatures is fully considered, and the accuracy of the detection result is improved.

[0023] In the preferred embodiment of the present application, in S1, the relationship between the temperature on the low-temperature side of the non-thermal barrier coating structure and the temperature difference between the two sides is fitted by using the least square method. Further, the relationship between the temperature on the low-temperature side of the non-thermal barrier coating structure and the temperature difference between the two sides is specifically t1=λ1+λ2T a5 , wherein T a5 is the temperature on the low-temperature side of the base layer of the thermal barrier coating structure, and λ1 and λ2 are both constants.

[0024] The beneficial effect is that by fitting the data of the low-temperature side temperature and the temperature difference between the two sides, the corresponding data of all low-temperature side temperatures and the temperature difference between the two sides in the fitting interval can be obtained.

[0025] In the preferred embodiment of the present application, in S2, the material, organization, size and surface roughness of the base and the non-thermal barrier coating structure are the same.

[0026] The beneficial effect is that since the material, organization, size and surface roughness of the base and the non-thermal barrier coating structure are the same, when the low-temperature side temperature is the same, the temperature on both sides of the base of the thermal barrier coating structure and the temperature on both sides of the non-thermal barrier coating structure can be ensured to be the same.

[0027] In the preferred embodiment of the present application, in S1, the non-thermal barrier coating structure is tested, and under the condition that the cooling airflow is unchanged, the non-thermal barrier coating structure is subjected to high-temperature airflow of different temperatures. Each time the test is repeated, the temperature on the high-temperature side and the low-temperature side of the non-thermal barrier coating structure is detected.

[0028] The beneficial effect is that the present application fully considers the temperature gradient of the base at different temperatures, and improves the accuracy of the detection result.

[0029] In the preferred embodiment of the present application, in S2, when the thermal barrier coating structure is detected, the thermal barrier coating structure is subjected to high-temperature airflow and cooling airflow, wherein the setting of the cooling airflow is the same as that when the non-thermal barrier coating structure is tested. Further, the same setting of the cooling airflow includes the same setting of the cooling airflow temperature, the cooling airflow speed and the cooling airflow path.

[0030] The beneficial effect is that by setting the cooling airflow in the same way in the detection of the non-thermal barrier coating structure and the thermal barrier coating structure, even if the cooling airflow temperature, the cooling airflow speed and the cooling airflow path are the same, the consistency of the detection environment of the non-thermal barrier coating structure and the thermal barrier coating structure can be ensured, so that the detection structure is more accurate.

[0031] A preferred embodiment of the present invention further includes S4, storing the temperatures of the high-temperature side and the low-temperature side of the thermal barrier-free coating structure, the fitting relationship between the low-temperature side temperature of the thermal barrier-free coating structure and the temperature difference between the two sides of the thermal barrier-free coating structure, and the heat insulation effect of the obtained thermal barrier coating.

[0032] The beneficial effect is that by storing the temperature of the high-temperature side and the low-temperature side of the thermal barrier coating structure, and the fitting relationship between the low-temperature side temperature of the thermal barrier coating structure and the temperature difference between the two sides of the thermal barrier coating structure, the stored data can be reused for future measurements of thermal barrier coating structures on the same substrate, which greatly reduces the workload of thermal insulation performance testing. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of a two-layer thermal barrier coating model structure in the prior art.

[0034] Figure 2 This is a flowchart of the method for detecting the thermal insulation effect of the thermal barrier coating of the present invention;

[0035] Figure 3 This is a schematic diagram of the temperature of the thermal barrier coating system in the thermal barrier coating insulation effect detection method of the present invention;

[0036] Figure 4 Finite element model and boundary condition diagram of a structure with thermal barrier coating;

[0037] Figure 5 The result diagram is shown in the finite element model solution of the structure with thermal barrier coating;

[0038] Figure 6 Using GH4099 alloy substrate, Δt1 and T a5 A graph showing the fitting relationship between them;

[0039] Figure 7 The temperature changes inside the alloy surface at 1473 K, 1573 K, 1673 K, and 1773 K, respectively, using a GH4099 alloy substrate.

[0040] Figure 8 for Figure 7 Temperature difference diagrams at both ends of the surface of the medium alloy at temperatures of 1473 K, 1573 K, 1673 K, and 1773 K respectively;

[0041] Figure 9 This is a schematic diagram showing the results of testing the temperature at both ends of the substrate layer of a thermal barrier-free coated structure using existing methods. Detailed Implementation

[0042] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described below are only for explaining the present invention and do not limit the scope of protection of the present invention.

[0043] The present invention will be further described in detail below through preferred embodiments:

[0044] As attached Figure 2 As shown: This embodiment discloses a method for testing the thermal insulation effect of a thermal barrier coating, including the following:

[0045] S1. Based on the temperatures of the high-temperature side and low-temperature side of the non-thermal barrier coated structure at different temperatures, fit the relationship between the low-temperature side temperature of the non-thermal barrier coated structure and the temperature difference between the two sides of the non-thermal barrier coated structure.

[0046] S2. Detect the surface temperature of the thermal barrier coated structure and the temperature of the low-temperature side of the substrate. The substrate is the same as the structure without thermal barrier coating. Determine the high-temperature temperature of the substrate of the thermal barrier coated structure based on the relationship between the low-temperature side temperature of the structure without thermal barrier coating and the temperature difference between the two sides of the structure without thermal barrier coating.

[0047] S3. The thermal insulation effect of the thermal barrier coating is obtained by subtracting the temperature of the high-temperature side of the substrate from the surface temperature of the thermal barrier coating structure.

[0048] In S1, the relationship between the temperature on the low-temperature side of the thermal barrier-free coated structure and the temperature difference between the two sides is fitted using the least squares method. Specifically, the relationship between the temperature on the low-temperature side of the thermal barrier-free coated structure and the temperature difference between the two sides is as follows: t1=λ1+λ2T a5 , where λ1 and λ2 are both constants.

[0049] The principle is as follows: In a Cartesian coordinate system, consider an arbitrary infinitesimal hexahedron element; the inflow and outflow of energy in the system are balanced. Assume the value of the internal heat source is Φ̇. The differential equation for three-dimensional transient heat conduction is as follows.

[0050]

[0051] Where ρ is density, c is heat capacity, λ is thermal conductivity, and ∂t / ∂x, ∂t / ∂y, and ∂t / ∂z are the rates of temperature change in the x, y, and z directions, respectively. Density and heat capacity are required in transient heat transfer simulations.

[0052] When the parameters of the thermal barrier-free coated structure are constant and there is no heat source in the heat transfer system, solving the steady-state equation and simplifying the above equation yields the Laplace equation as shown below.

[0053]

[0054] For single-layer plane model, the steady-state solution is obtained, and the temperature variation in one coordinate direction is obtained, and the Laplace equation is expressed as follows:

[0055] =0

[0056] T1 (i.e. T b1 ) and T2 (i.e. T b2 ) are the temperatures on both sides of the thermal barrier coating structure, and the boundary conditions are x = 0, t = T1 and x = δ, t = T2. The finally obtained Laplace equation is continuously integrated twice, and the solution is as follows: the temperature at any point on the single-layer plane model is as follows:

[0057] x + T1.

[0058] In S1, the thermal barrier coating structure is tested, and the thermal barrier coating structure is subjected to high-temperature gas flow with different temperatures under the condition that the cooling gas flow is unchanged. Each time the test is repeated, the temperature of the high-temperature side and the low-temperature side of the thermal barrier coating structure is detected.

[0059] In S2, the substrate and the thermal barrier coating structure are the same in material, organization, size and surface roughness.

[0060] In S2, when the thermal barrier coating structure is detected, the thermal barrier coating structure is subjected to high-temperature gas flow and cooling gas flow, and the cooling gas flow is set in the same way as when the thermal barrier coating structure is tested. Specifically, the cooling gas flow is set in the same way, including the cooling gas flow temperature, the cooling gas flow speed and the cooling gas flow path setting.

[0061] The embodiment also includes S4, which stores the temperature of the high-temperature side and the low-temperature side of the thermal barrier coating structure, the fitting relationship between the temperature of the low-temperature side of the thermal barrier coating structure and the temperature difference between both sides of the thermal barrier coating structure, and the obtained thermal insulation effect of the thermal barrier coating.

[0062] As Figure 3 shown is a schematic diagram of the temperature of the thermal barrier coating system, which is ceramic layer TBC, oxidation layer TGO, bonding layer BC and substrate layer substrate from left to right, and the high-temperature heat flow is on the left side of the thermal barrier coating, and the cold flow is on the right side of the substrate. The thermal insulation performance of the thermal barrier coating is expressed as formula (1), and formula (1) is as follows:

[0063] Δt = T a1 -T a4； …… (1), T a1 is the surface temperature of the heat source side of the thermal barrier coating structure, and T a4 is the temperature at the interface position of the bonding layer and the substrate layer of the thermal barrier coating structure.

[0064] The temperature difference between the two sides of the substrate layer is represented by equation (2), which is:

[0065] Δt1=T a4 -T a5 ; …… (2), T a5 is the temperature of the low-temperature side of the substrate layer of the thermal barrier coating structure.

[0066] T a1 and T a5 can be directly measured by an infrared thermometer;

[0067] From equation (1) and equation (2), the heat insulation performance of the thermal barrier coating is equation (3):

[0068] T a1 -T a4 =T a1 - (T a5 + Δt1) …… (3);

[0069] In this formula, the temperatures of T a1 and T a5 can be directly measured by an infrared thermometer, and the temperature of the high-temperature side of the substrate of the thermal barrier coating structure can be obtained according to the relationship between the low-temperature side temperature of the substrate and the temperature difference between the two sides of the structure without thermal barrier coating, so as to obtain the heat insulation performance of the thermal barrier coating.

[0070] More specifically, the steps of the thermal barrier coating heat insulation effect detection method of the present embodiment are as follows:

[0071] Step 1. Sample preparation: prepare two identical substrates A and B (the material, organization, size, and surface roughness are all the same), and spray a thermal barrier coating system on substrate A, and do not spray on substrate B. Wherein A is the sample to be tested, and B is the reference sample. The present method mainly studies the heat insulation performance of sample A.

[0072] Step 2. Sample testing: place the reference sample B in the thermal test device. The reference sample B is subjected to high-temperature heat flow and cooling air flow. Adjust the appropriate cooling air flow, and repeat the operation under the condition that the cooling air flow remains unchanged, and set different temperature of the high-temperature air flow. The temperature of the two sides of the reference sample B is different, and the infrared thermometer is used to measure the temperature of the two sides of the reference sample B. The temperature difference between the two sides of the reference sample B is Δt1, and the low-temperature measurement temperature of the reference sample B is T a5 . As shown in Figure 3 , the least squares method is used to fit the relationship between the temperature T a5 of the low-temperature side of the reference sample B and the temperature difference Δt1.

[0073] Step 3. Testing Sample A: Place sample A in the thermal testing device. Sample A is subjected to a high-temperature heat flow and a cooling airflow. The cooling airflow settings are the same as in Step 2. Measure the temperature T on the low-temperature side of the substrate of sample A using an infrared thermometer. a5 .

[0074] Step 4. Take the low-temperature side temperature T measured in Step 3. a5 Substituting this into the fitting relationship calibrated in step 2, we obtain the temperature difference Δt1 between the two sides of the substrate.

[0075] Step 5. Place T a5 Substituting the values ​​of Δt1 and Δt1 into formula (2), the temperature T at the interface between the substrate and the adhesive layer is obtained. a4 .

[0076] Step 6. Measure the surface temperature T of the sample A to be tested using an infrared thermometer. a1 Then the thermal insulation capacity of the thermal barrier coating is calculated as T. a1 -T a4。

[0077] It should be clarified that although the test sample A and the reference sample B use the same cooling airflow during testing, the low-temperature side temperature of the substrate of the test sample A will be different from that of the reference sample B (which is a structural component without a thermal barrier coating) due to the effect of the thermal barrier coating.

[0078] The principle of the method for detecting the thermal insulation effect of thermal barrier coatings in this invention is as follows: First, the temperature T on the low-temperature side of the structural component without thermal barrier coating is fitted using the least squares method. a5 The relationship between the temperature difference Δt1 and the thermal conduction law of the non-thermal barrier coated structure (alloy material) is known. Based on this, the temperature of the low-temperature side of the substrate of the thermal barrier coated structure is measured under the same cooling airflow (this temperature is different from the low-temperature side temperature of the non-thermal barrier coated structure under the same cooling airflow). Since the thermal conduction law of the substrate is constant, the temperature can be substituted into the fitted relationship to obtain the temperature difference Δt1. Then, based on formula (2), the temperature T at the interface between the substrate and the adhesive layer is obtained. a4 The temperature T obtained at this time a4 This refers to the accurate temperature at the interface between the base layer and the adhesive layer of a thermal barrier coated structural component.

[0079] Among them, the least squares method was used to fit the temperature T on the low-temperature side of the thermal barrier-free coating structure. a5 When determining the relationship between the temperature difference Δt1 and the coordinates, data for all points within the fitting interval can be obtained using finite coordinate data. The principle of fitting is as follows: for a given set of data (xi, yi), assume it satisfies an nth-degree polynomial:

[0080]

[0081] To find the optimal solution of each order parameter, the sum of the square of the difference between the value calculated by the n-th order polynomial and yi should be minimum for each xi, i.e.:

[0082] .

[0083] Verification experiment - measure the thermal insulation performance of YTaO4 coating prepared on GH4099 alloy using the method.

[0084] To verify the effect of the method, the temperature T a4， at the interface between the substrate layer and the bonding layer is calculated using the finite element method. a1 The difference between this temperature and the surface temperature T a4 on the high-temperature side of the thermal barrier coating structure is the thermal insulation performance of the thermal barrier coating.

[0085] Then, the thermal insulation performance of the thermal barrier coating system is measured using the method. The results of the method and the finite element method are compared.

[0086] (1) Establish a finite element model of a structure with a thermal barrier coating: a bonding layer, an oxidation layer, and a ceramic layer are prepared on the surface of the substrate, and their materials are GH4099, NiCoCrAlY, Al2O3, and YTaO4, respectively, with thicknesses of 3 mm, 0.1 mm, 0.03 mm, and 0.3 mm, respectively. The boundary conditions are to investigate the service of the system at a temperature of 1773 K, and the cooling gas temperature is 873 K. When the temperature in the system is constant, the steady state is reached, and the thermal insulation performance of the thermal barrier coating system is calculated. The finite element model and boundary conditions are shown in Figure 4 . Establish a finite element model of a structure without a thermal barrier coating: the model only has a substrate layer, and its material is GH4099 with a thickness of 3 mm, and the boundary conditions are the same as above.

[0087] Solve the finite element model and derive the temperature T a4 : the results of the finite element model of the structure with a thermal barrier coating are shown in Figure 5 , Figure 5 which shows the temperature variation of each layer in the thermal barrier coating system. The temperature T a4 at the interface between the substrate and the BC is 1253 K, and the thermal insulation performance of the coating is 520 K.

[0088] (2) Measure the thermal insulation performance of the thermal barrier coating at 1773 K using the method.

[0089] (a) Calibration sample: for GH4099 alloy with thickness of 3mm, a substrate without thermal barrier coating is prepared, and the temperature T of the substrate is measured at 1773K, 1673K, 1573K, 1473K respectively, and the temperature difference Δt1 between two ends of the substrate is measured, and the relationship between the temperature difference Δt1 between two ends of the substrate and T is fitted, as shown in the following formula: a5 t1=-86.96+0.155T a5 Figure 6 t1=-86.96+0.155T a5。

[0090] (b) Solving T a4 and Δt1

[0091] Adjusting the heat flow, the surface temperature of the structure with thermal barrier coating is measured to be 1773K, i.e. T a1 is 1773K, and the temperature T a5 of the low-temperature side of the substrate layer is 1166K, and T a5 is substituted into the fitted relationship to obtain Δt1=93.75. Then Δt1 and T a5 are substituted into T a1 -T a4 =T a1 -(T a5 +Δt1) to obtain 1773-T a4 =1773-(1166+0.155×Ta5-86.96), and thus T a4 =1259.75 K, and Δt= T a1 - T a4 =513.25K.

[0092] Compared with the results derived from the finite element simulation, the absolute error of T a4 and Δt1 measured by the method is 7 K, and the error is mainly derived from the data fitting process and rounding error.

[0093] The method has the following technical effects:

[0094] (1) The equipment is simple, only an examination device is needed, and the temperature can be directly measured by using an infrared gun, without the need of additionally setting a thermocouple. The detection cost is reduced, and the accuracy of the experiment is also increased.

[0095] (2) For samples of the same substrate, the fitted results can be reused once the calibration is performed, which greatly reduces the workload of the thermal insulation performance test.

[0096] ​​(3) Compared with other methods, it fully considers the temperature gradient of the substrate at different experimental temperatures, which increases the accuracy of the experimental results.

[0097] If the scheme of patent CN202111154914.X is used, the temperatures at both ends of the substrate layer of the thermal barrier-free coating structure are tested. The temperature of the low-temperature side is adjusted to 1166 K, and the temperature of the high-temperature side is arbitrary. The final calculation results are shown in the attached figure. Figure 9 As shown.

[0098] As attached Figure 9 As shown, the temperature on the low-temperature side of the substrate meets the requirements of patent CN202111154914.X (the substrate temperature of the structure without thermal barrier coating is the same as that of the structure with thermal barrier coating, 1166 K). However, the simulation results show a high-temperature side temperature of 1288 K, and the temperature difference between the two sides of the substrate is 122 K. Therefore, the thermal insulation performance of the thermal barrier coating is 1773 - 1166 - 122 = 485 K. The result obtained through finite element simulation is 520 K. Therefore, the method has an error of 35 K. This error stems from the fact that the patent does not consider the influence of the substrate surface temperature on the temperature difference between the two sides of the substrate, nor does it consider the influence of the substrate cooling airflow temperature and cooling airflow path on the substrate temperature difference.

[0099] The preferred embodiments of this application have been described in detail above with reference to the accompanying drawings. Typical known structures and common knowledge techniques in the preferred embodiments have not been described in detail here. Those skilled in the art can improve and implement the technical solutions of this invention based on the guidance provided in these embodiments and their own capabilities. Some typical known structures, known methods or common knowledge techniques should not be obstacles for those skilled in the art to implement this application.

[0100] The scope of protection claimed in this application shall be determined by the contents of its claims, and the contents described in the invention description, specific embodiments and drawings shall be used to interpret the claims.

[0101] Within the scope of the technical concept of this application, several modifications can be made to the specific implementation of this application, and these modified implementations should also be considered within the protection scope of this application.

Claims

1. A method for testing the thermal insulation effect of a thermal barrier coating, characterized in that, Includes the following: S1. Based on the temperatures of the high-temperature side and low-temperature side of the thermal barrier-free coated structure at different temperatures, fit the relationship between the low-temperature side temperature of the thermal barrier-free coated structure and the temperature difference between the two sides of the thermal barrier-free coated structure. In S1, the thermal barrier-free coated structure is tested. Under the condition that the cooling airflow is constant, the thermal barrier-free coated structure is subjected to high-temperature airflow at different temperatures. Each time it is repeated, the temperature of the thermal barrier-free coated structure on the high-temperature side and the low-temperature side is detected. In S1, the relationship between the temperature on the low-temperature side of the thermal barrier-free coated structure and the temperature difference between the two sides is fitted using the least squares method. Specifically, the relationship between the temperature on the low-temperature side of the thermal barrier-free coated structure and the temperature difference between the two sides is as follows: t1=λ1+λ2T a5 T a5 λ1 and λ2 are constants, where λ1 and λ2 are the low-temperature side temperature of the substrate layer of the thermal barrier coating structure. S2. Detect the surface temperature of the thermal barrier coating structure and the temperature of the low-temperature side of the substrate. The substrate is the same as the structure without a thermal barrier coating. Based on the relationship between the low-temperature side temperature of the structure without a thermal barrier coating and the temperature difference between the two sides of the structure without a thermal barrier coating, determine the temperature of the high-temperature side of the substrate of the thermal barrier coating structure. In S2, when testing the thermal barrier coating structure, the thermal barrier coating structure is subjected to high-temperature airflow and cooling airflow. The cooling airflow settings are the same as those for the test of the structure without a thermal barrier coating. The same cooling airflow settings include the same cooling airflow temperature, cooling airflow speed, and cooling airflow path settings. S3. The thermal barrier coating's insulation effect is obtained by subtracting the temperature of the high-temperature side of the substrate from the surface temperature of the thermal barrier coating structure.

2. The method for testing the thermal insulation effect of thermal barrier coatings according to claim 1, characterized in that: In S2, the substrate and the thermal barrier-free coating structure have the same material, microstructure, size and surface roughness.

3. The method for testing the thermal insulation effect of thermal barrier coatings according to claim 1, characterized in that: It also includes S4, which stores the temperatures of the high-temperature side and the low-temperature side of the thermal barrier-free coated structure, the fitting relationship between the low-temperature side temperature of the thermal barrier-free coated structure and the temperature difference between the two sides of the thermal barrier-free coated structure, and the heat insulation effect of the obtained thermal barrier coating.

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