A method for estimating the temperature measurement error of gas turbine blades.

Abstract

This invention discloses a method for estimating the temperature measurement error of gas turbine blades, comprising the following steps: calculating the heat transfer coefficient and temperature of the outer surface and the inner surface of the blade based on the geometric characteristics of the outer surface and the test conditions; importing the heat transfer coefficient and temperature of the outer surface and the inner surface into a thermocouple embedding model for heat conduction calculation to obtain a first temperature measurement result; this invention establishes an ideal thermocouple embedding model, calculates the first temperature measurement result, establishes a thermocouple embedding model for three sets of blades considering installation deviations based on the thermocouple installation process, obtains a second temperature measurement result, and obtains the deviation of the metal temperature measurement result caused by the thermocouple installation deviation based on the first and second temperature measurement results, comprehensively considering the thermocouple installation deviation to improve the accuracy of turbine blade temperature measurement in gas turbine tests.

Description

Technical Field

[0001] This invention relates to the field of gas turbine testing technology, and in particular to a method for estimating the measurement error of gas turbine blade temperature. Background Technology

[0002] Turbine blades are one of the core components of gas turbines, and their cooling design is crucial to blade design. Tests on the external heat transfer coefficient of blades, blade cooling efficiency, turbine components, and the entire gas turbine all involve measuring the temperature of turbine blades. These measurements provide important information for blade cooling design and serve as crucial references for blade performance evaluation. Currently, micro thermocouples are widely used both domestically and internationally to measure blade temperature. Due to improvements in thermocouple manufacturing, calibration, and testing technologies, the measurement error of thermocouples themselves is very small, and the error range is well-defined, with abundant experimental data and literature available for reference. However, there are few reports on temperature measurement errors caused by thermocouple embedding errors. Therefore, there is an urgent need to establish a method for predicting the error range of thermocouple temperature measurement for gas turbine blades to help blade designers conduct more accurate and precise experimental data analysis and improve blade cooling design capabilities.

[0003] For example, Chinese patent CN201510937374.0 discloses a turbine blade temperature measurement method based on air spraying. First, the turbine blade surface is pretreated to remove foreign matter. Second, a high-temperature insulating adhesive is sprayed using an air spraying process to prepare an insulating layer. Third, a thermocouple is fixed on the blade. Finally, a high-temperature insulating adhesive is sprayed again to prepare a protective layer. The turbine blade temperature measurement in this application does not consider the installation deviation of the thermocouple and the temperature measurement error caused by the installation deviation, resulting in a large error and low accuracy in the final turbine blade temperature measurement result. Summary of the Invention

[0004] This invention primarily addresses the problem that existing turbine blade temperature measurement tests cannot estimate measurement errors caused by thermocouple installation deviations. It provides a method for estimating the temperature measurement error of gas turbine blades, comprehensively considering thermocouple installation deviations to improve the accuracy of turbine blade temperature measurement in gas turbine tests.

[0005] The above-mentioned technical problem of the present invention is mainly solved by the following technical solution: a method for estimating the temperature measurement error of a gas turbine blade, comprising the following steps: calculating the heat transfer coefficient and heat transfer temperature of the outer surface and the inner surface of the blade according to the geometric characteristics of the outer surface and the test conditions; importing the heat transfer coefficient and heat transfer temperature of the outer surface and the inner surface of the blade into a thermocouple embedding model, performing heat conduction calculations to obtain a first temperature measurement result; determining the deviation range of the thermocouple installation in the depth direction, width direction, and blade height direction according to the thermocouple installation process, sampling the thermocouple installation deviations in the three directions respectively, and establishing three sets of thermocouple embedding models of the blade considering the installation deviations; performing heat conduction calculations on the thermocouple embedding models to obtain a second temperature measurement result considering the thermocouple embedding deviations; and obtaining the deviation of the metal temperature measurement result caused by the thermocouple installation deviations by comparing and calculating the first temperature measurement result and the second temperature measurement result.

[0006] As a preferred method, the calculation methods for the heat transfer coefficients of the outer and inner surfaces are as follows:

[0007]

[0008]

[0009] Among them, h g h represents the heat transfer coefficient of the outer surface. c Re represents the internal surface heat transfer coefficient, where C0 and C1 are constants; Re g Pr g k g L g These represent the Reynolds number, Prandtl number, thermal conductivity, and characteristic length of the gas flow under the test conditions; Re c Pr c k c L c These are the Reynolds number, Prandtl number, thermal conductivity, and characteristic length of the cold air flow under the test conditions.

[0010] Preferably, the method for calculating the first temperature measurement result is as follows: Three mutually orthogonal directions are established on the blade: depth direction H, width direction L, and blade height direction R. The size of the thermocouple slot is set to H1 mm × L1 mm. Ideally, the thermocouple installation dimensions are: depth direction H0, width direction L0, and blade height direction R0, resulting in a thermocouple embedding model. The thermocouple embedding model is divided into three parts: the blade, the thermocouple, and the coating that fixes the thermocouple. The thermocouple embedding model is meshed. The thermophysical properties of the materials of the three components of the thermocouple embedding model are set. The heat transfer coefficient and temperature of the outer surface of the blade, and the heat transfer coefficient and temperature of the inner surface of the blade are used as heat transfer boundary conditions and imported into the thermocouple embedding model for heat conduction calculation to obtain the first temperature measurement result T0 of the embedding model.

[0011] Preferably, the method for establishing the thermocouple insertion model is as follows: based on the maximum deviation of the thermocouple installation, the following deviations are obtained: the depth deviation of the thermocouple installation is ±ΔH, the width deviation is ±ΔL, and the blade height deviation is ±ΔR; the sample sets of thermocouple installation positions in the three directions are obtained as {H}, {L}, and {R}, respectively.

[0012]

[0013]

[0014]

[0015] n, m, and s are positive integers, and the number of sampling points in the three directions are 2n+1, 2m+1, and 2s+1, respectively. A thermocouple filling model that takes into account installation deviation is established, and there are a total of three models.

[0016] As a preferred option, the thermocouple-filled model is meshed and thermal conductivity calculations are performed;

[0017] The second temperature measurement result, which takes into account the embedment deviation of the thermocouple depth, is as follows:

[0018] {TH} = {TH1, TH2, ..., TH} 2n+1};

[0019] The second temperature measurement result, taking into account the embedment deviation in the width direction of the thermocouple, is as follows:

[0020] {TL} = {TH1, TH2, ..., TH} 2m+1};

[0021] The second temperature measurement result, taking into account the embedment deviation of the thermocouple blade in the height direction, is as follows:

[0022] {TR} = {TR1, TR2, ..., TR} 2s+1};

[0023] Among them, {TH}, {TL}, and {TR} are the sets of temperature measurement results of thermocouple embedment deviation in three directions, respectively.

[0024] Preferably, the deviation and maximum deviation value of the metal temperature measurement results caused by the thermocouple installation deviation are calculated based on the first temperature measurement result T0 and the second temperature measurement results of the embedding deviation in the depth direction, the embedding deviation in the width direction, and the embedding deviation in the blade height direction.

[0025] The beneficial effects of this invention are as follows: This invention proposes for the first time in related applications and fields an evaluation method for the error range of thermocouples. By establishing an ideal thermocouple embedding model, the first temperature measurement result is calculated. Based on the thermocouple installation process, a thermocouple embedding model for three sets of blades considering installation deviations is established to obtain the second temperature measurement result. Based on the first and second temperature measurement results, the deviation of the metal temperature measurement result caused by the thermocouple installation deviation is obtained. The thermocouple installation deviation is comprehensively considered, which improves the accuracy of temperature measurement of turbine blades in gas turbine tests, helps blade designers to conduct more accurate and detailed test data analysis, and improves the level of blade cooling design. It is applicable to various test conditions and various thermocouple embedding methods. Attached Figure Description

[0026] Figure 1 This is a schematic flowchart of the measurement error estimation method according to an embodiment of the present invention. Detailed Implementation

[0027] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that, unless otherwise specified, the following embodiments and features described therein can be combined with each other.

[0028] To make the objectives, technical solutions, and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only for explaining the present invention and are not intended to limit the invention.

[0029] Example: A method for estimating the temperature measurement error of a gas turbine blade, such as... Figure 1 As shown, it includes the following steps:

[0030] Step (1): Heat transfer temperature T on the outer surface of the bladeg and the internal surface heat transfer temperature T c The heat transfer coefficient h of the outer surface of the blade is determined according to the experimental conditions and can be directly measured. g and the internal surface heat transfer coefficient h c Calculate according to the following formula:

[0031]

[0032]

[0033] Where C0 and C1 are constants; Re g Pr g k g L g These represent the Reynolds number, Prandtl number, thermal conductivity, and characteristic length of the gas flow under the test conditions; Re c Pr c k c L c These are the Reynolds number, Prandtl number, thermal conductivity, and characteristic length of the cold air flow under the test conditions.

[0034] Step (2): First, analyze the ideal thermocouple embedding model. Establish three mutually orthogonal directions on the blade: depth direction H, width direction L, and blade height direction R. Set the thermocouple slot size to H0 mm (depth direction) × L0 mm (width direction). Divide the thermocouple embedding model into three parts: blade, thermocouple, and coating that fixes the thermocouple. Mesh the thermocouple embedding model. Set the thermophysical properties of the materials of the three components in the calculation program. Apply the heat transfer coefficient and heat transfer temperature of the outer surface of the blade, and the heat transfer coefficient and heat transfer temperature of the inner surface of the blade obtained in step (1) as heat transfer boundary conditions to the ideal thermocouple embedding model, and perform heat conduction calculation to obtain the temperature measurement result T0 of the ideal model.

[0035] Step (3): Based on the thermocouple installation process, determine the depth deviation of the thermocouple installation as ±ΔH, the width deviation as ±ΔL, and the blade height deviation as ΔR. Obtain the sample sets {H}, {L}, and {R} of the thermocouple installation positions in each direction according to the following sampling method. Wherein, n, m, and s are positive integers, and the number of sampling points in the three directions are 2n+1, 2m+1, and 2s+1 respectively.

[0036]

[0037]

[0038]

[0039] For each element in the three sets mentioned above, an embedding model of the thermocouple is established. A total of three sets of models are obtained, with the number of models being 2n+1, 2m+1, and 2s+1, respectively.

[0040] Step (4): Divide the three sets of models obtained in step (3) into meshes, and perform heat conduction calculations for each model according to step (2).

[0041] The temperature measurement results, taking into account the embedment deviation of the thermocouple depth, are as follows:

[0042] {TH} = {TH1, TH2, ..., TH} 2n+1};

[0043] The temperature measurement results, taking into account the embedment deviation in the width direction of the thermocouple, are as follows:

[0044] {TL} = {TH1, TH2, ..., TH} 2m+1};

[0045] The temperature measurement results, taking into account the embedment deviation of the thermocouple blade in the height direction, are as follows:

[0046] {TR} = {TR1, TR2, ..., TR} 2s+1};

[0047] Among them, {TH}, {TL}, and {TR} are the sets of temperature measurement results of thermocouple embedment deviation in three directions, respectively.

[0048] Step (5): The temperature measurement deviation caused by the installation deviation in the depth direction of the thermocouple installation is calculated according to the following formula, where {ΔTH} is the set of temperature measurement deviation values ​​caused by the installation deviation in the depth direction of the thermocouple installation, and the maximum value in this set is the maximum temperature measurement deviation caused by the installation deviation in the depth direction of the thermocouple installation.

[0049] {ΔTH}={TH1-T0, TH2-T0,…, TH 2n+1 -T0};

[0050] The temperature measurement deviation caused by the installation deviation in the width direction of the thermocouple is calculated according to the following formula, where {ΔTL} is the set of temperature measurement deviation values ​​caused by the installation deviation in the width direction of the thermocouple, and the maximum value in this set is the maximum temperature measurement deviation caused by the installation deviation in the width direction of the thermocouple.

[0051] {ΔTL}={TH1-T0, TH2-T0,…, TH 2m+1 -T0};

[0052] The temperature measurement deviation caused by the installation deviation in the blade height direction of the thermocouple is calculated according to the following formula, where {ΔTR} is the set of temperature measurement deviation values ​​caused by the installation deviation in the blade height direction of the thermocouple, and the maximum value in this set is the maximum temperature measurement deviation caused by the installation deviation in the blade height direction of the thermocouple.

[0053] {ΔTR}={TR1-T0, TR2-T0,…, TR 2s+1 -T0}.

[0054] This invention is applicable to various test conditions and various thermocouple embedding methods. For different test conditions, only the relevant parameters in steps (1) and (2) need to be modified. For different thermocouple models and thermocouple embedding processes, only the relevant parameters in steps (3) and (4) need to be modified.

[0055] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the present invention in any way. Other variations and modifications are possible without departing from the technical solutions described in the claims.

Claims

1. A method for estimating the measurement error of gas turbine blade temperature, characterized in that, Includes the following steps: Based on the geometric characteristics of the outer surface of the blade and the test conditions, calculate the heat transfer coefficient and heat transfer temperature of the outer surface and the heat transfer coefficient and heat transfer temperature of the inner surface of the blade. The heat transfer coefficient and temperature of the outer surface and the heat transfer coefficient and temperature of the inner surface of the blade are imported into the thermocouple embedding model for heat conduction calculation to obtain the first temperature measurement result. The thermocouple embedding model consists of three parts: blade, thermocouple and coating for fixing thermocouple, and is divided into grids and the thermophysical properties of each part are set. Based on the thermocouple installation process, the deviation ranges in the depth, width, and blade height directions of the thermocouple installation were determined. The thermocouple installation deviations in the three directions were sampled, and thermocouple insertion models for three sets of blades considering the installation deviations were established. Thermal conductivity calculations were performed on the thermocouple insertion models to obtain the second temperature measurement results in the three directions considering the thermocouple embedding deviations. By comparing the first and second temperature measurement results, the deviation of the metal temperature measurement results caused by the thermocouple installation deviations was obtained.

2. The method for estimating the temperature measurement error of a gas turbine blade according to claim 1, characterized in that, The calculation methods for the heat transfer coefficient of the outer surface and the heat transfer coefficient of the inner surface are as follows: Among them, h g h represents the heat transfer coefficient of the outer surface. c Re represents the internal surface heat transfer coefficient, where C0 and C1 are constants; Re g Pr g k g L g These represent the Reynolds number, Prandtl number, thermal conductivity, and characteristic length of the gas flow under the test conditions; Re c Pr c k c L c These are the Reynolds number, Prandtl number, thermal conductivity, and characteristic length of the cold air flow under the test conditions.

3. The method for estimating the temperature measurement error of a gas turbine blade according to claim 1, characterized in that, The calculation method for the first temperature measurement result is as follows: establish three mutually orthogonal directions on the blade: depth direction H, width direction L, and blade height direction R. Set the size of the thermocouple groove to H1 mm × L1 mm. Under ideal conditions, the installation dimensions of the thermocouple are: depth direction H0, width direction L0, and blade height direction R0, thus obtaining the thermocouple burial model. The heat transfer coefficients and temperatures of the outer and inner surfaces of the blades are used as heat transfer boundary conditions and imported into the thermocouple burial model for thermal conductivity calculation, resulting in the first temperature measurement result T0 of the burial model.

4. The method for estimating the temperature measurement error of a gas turbine blade according to claim 3, characterized in that, The method for establishing the thermocouple insertion model is as follows: Based on the maximum deviation of thermocouple installation, the following deviations are obtained: the depth deviation of thermocouple installation is ±ΔH, the width deviation is ±ΔL, and the blade height deviation is ±ΔR; the sample sets of thermocouple installation positions in the three directions are obtained as {H}, {L}, and {R}, respectively. n, m, and s are positive integers, and the number of sampling points in the three directions are 2n+1, 2m+1, and 2s+1, respectively. A thermocouple filling model that takes into account installation deviation is established, and there are a total of three models.

5. The method for estimating the temperature measurement error of a gas turbine blade according to claim 4, characterized in that, The thermocouple-filled model is meshed and thermal conductivity calculations are performed. The second temperature measurement result, which takes into account the embedment deviation of the thermocouple depth, is as follows: {TH}={TH1,TH2,……,TH 2n+1 }; The second temperature measurement result, taking into account the embedment deviation in the width direction of the thermocouple, is as follows: {TL}={TH1,TH2,……,TH 2m+1 }; The second temperature measurement result, taking into account the embedment deviation of the thermocouple blade in the height direction, is as follows: {TR}={TR1,TR2,……,TR 2s+1 }; Among them, {TH}, {TL}, and {TR} are the sets of temperature measurement results of thermocouple embedment deviation in three directions, respectively.

6. The method for estimating the temperature measurement error of a gas turbine blade according to claim 5, characterized in that, The deviation of the metal temperature measurement result caused by the thermocouple installation deviation and the maximum deviation value are calculated based on the first temperature measurement result T0, the second temperature measurement result of the embedding deviation in the depth direction, the second temperature measurement result of the embedding deviation in the width direction, and the second temperature measurement result of the embedding deviation in the blade height direction.

Images