Thermocouple pre-embedding method and pre-embedding structure for turbine blade wall surface temperature monitoring

Abstract

The invention discloses a thermocouple pre-embedding method and pre-embedding structure for turbine blade wall surface temperature monitoring, which is applied to the field of aero-engines, and comprises the following steps: determining the predicted wall surface temperature of a turbine blade according to a used metal material and a cooling hole dividing structure, and selecting a pre-embedded thermocouple model and a thermocouple protection sleeve; selecting the diameter of the thermocouple wire and the diameter of the thermocouple protection sleeve according to the wall thickness of the thermocouple protection sleeve and the turbine blade; a plurality of thermocouple pre-embedded channels are designed in the wall surface, and a plurality of limiting structures are arranged at the corresponding positions of the inner surface of the wall surface; wherein the two ends of the channel are connected with the blade surface temperature measuring position and the lower end wall of the turbine blade and are staggered with the cooling holes without mutual influence; the thermocouples are inserted from a plurality of channel holes corresponding to the thermocouple pre-buried channels in the end face of the wall face, the temperature measuring end points abut against the corresponding limiting structures through the channels, and the channel holes are sealed through the laser cladding technology. According to the invention, high-precision monitoring of the turbine blade wall surface temperature is realized.

Description

Technical Field

[0001] The invention relates to the field of aviation engines, and in particular to a thermocouple pre-embedding method and pre-embedding structure for monitoring the wall temperature of turbine blades. Background Art

[0002] With the continuous development of advanced aviation engine technology, higher requirements are placed on the overall power of the engine. The temperature rise at the combustion chamber outlet continues to increase, developing towards the goal of more than 2000K, which is far beyond the melting point of most metal materials. This requirement poses a more severe test on the temperature resistance and aerodynamic performance of turbine blades. In order to ensure the reliable operation of the turbine blades, it is necessary to accurately monitor the surface temperature of the turbine blades to evaluate the reliability of the cooling system, further optimize the cooling design and improve efficiency. In addition, gas turbine blades work in a high-temperature, high-speed airflow environment, and accurate temperature monitoring is also crucial to their life, reliability and efficiency.

[0003] Existing turbine blade wall temperature measurement technologies are mainly divided into non-contact and contact methods, among which non-contact temperature measurement mainly includes thermosensitive coating method, infrared thermal imaging, and fluorescence temperature measurement method, and contact temperature measurement mainly includes thermocouple method and fiber optic temperature measurement method. The thermosensitive coating method sprays temperature-sensitive coating materials on the blade surface. The coating changes color at different temperatures and infers the temperature by color change. Although it has the advantage of not changing the blade structure and aerodynamic characteristics, its coating is easily affected by peeling, wear or ablation. At the same time, the temperature resolution is limited by the color change accuracy and is not suitable for fine temperature measurement; infrared thermal imaging infers the surface temperature through infrared radiation on the blade surface, but it requires good line of sight conditions and the temperature measurement accuracy is greatly affected by the gas flow and the emissivity of the blade surface; the fluorescence temperature measurement method sprays fluorescent materials on the blade surface. When the blade surface temperature rises, the fluorescence intensity or wavelength of the coating changes. The temperature is inferred by reading the fluorescence information through optical instruments, but its measurement process depends on external light sources. The light source needs to be stable and strong enough, and is greatly disturbed by environmental conditions such as airflow and light, making it difficult to apply to the interior of a turbine with a complex structure. Most non-contact methods are greatly affected by the environment, and their measurement results need to be corrected and calibrated, while the contact method provides a more accurate temperature measurement result. The thermocouple method measures temperature through the hot spot effect. According to the arrangement method, it can be divided into surface patch type and embedded thermocouple method. The surface patch method will not damage the blade structure, but it is greatly affected by airflow heat transfer and radiation heat transfer, and its results may deviate from the actual blade surface temperature; the embedded thermocouple method opens a channel on the blade wall, and the embedded thermocouple directly contacts the wall of the position to be measured. It is less affected by the environment and has the most reliable measurement accuracy. However, since the thermocouple channel may affect the strength of the blade structure, a fine channel design is required. The optical fiber temperature measurement method uses the response characteristics of optical fiber to temperature to measure temperature. It has high sensitivity and high measurement accuracy, but its cost is relatively high.

[0004] Therefore, how to provide a thermocouple pre-embedding method and pre-embedding structure for monitoring the wall temperature of turbine blades which has low cost, can realize high-precision monitoring of the wall temperature of turbine blades, and will not affect the original turbine blade profile and cooling structure is an urgent problem to be solved by technical personnel in this field. Summary of the invention

[0005] In view of this, the present invention proposes a thermocouple pre-embedding method and pre-embedding structure for monitoring the wall temperature of turbine blades.

[0006] In order to achieve the above object, the present invention adopts the following technical solution:

[0007] A thermocouple pre-embedding method for monitoring the wall temperature of a turbine blade comprises:

[0008] Step 1: Determine the expected wall temperature of the turbine blade according to the metal material used and the cooling hole structure of the turbine blade, and select the embedded thermocouple model and thermocouple protection sleeve according to the expected wall temperature, and select the thermocouple wire diameter and thermocouple protection sleeve diameter according to the thermocouple protection sleeve and the turbine blade wall thickness;

[0009] Step 2: Design multiple thermocouple pre-embedded channels inside the turbine blade wall, and set multiple limit structures at corresponding positions on the inner surface of the turbine blade wall to ensure that the thermocouple temperature measurement end points can be arranged at the specified temperature measurement positions; wherein, the two ends of the thermocouple pre-embedded channels are connected to the blade surface temperature measurement position and the lower end wall of the turbine blade, and are staggered with the cooling holes without affecting each other;

[0010] Step 3: Insert the thermocouple selected in step 1 through the multiple channel openings on the end surface of the turbine blade wall corresponding to the thermocouple pre-buried channels, make the temperature measuring end point of the thermocouple press against the corresponding limit structure through the thermocouple pre-buried channel, and seal the channel opening using laser cladding technology to tightly fix the thermocouple temperature measuring end point to the surface of the turbine blade.

[0011] Optionally, in step 1, the expected wall temperature of the turbine blade is determined according to the metal material used for the turbine blade and the cooling hole structure, specifically:

[0012] γ = α-β;

[0013] Among them, γ is the expected maximum wall temperature of the turbine blade; α is the maximum temperature of the metal material used while maintaining good mechanical properties; β is the temperature cooling effect provided by the cooling hole structure;

[0014] Based on the predicted maximum wall temperature γ of the turbine blade, it can be obtained that the predicted wall temperature of the turbine blade is within γ.

[0015] Optionally, in step 1, the embedded thermocouple model is selected according to the expected wall temperature, specifically:

[0016] When the wall temperature is expected to be within 1450K, select K-type and N-type thermocouples;

[0017] When the wall temperature is expected to be within 1850K, select the S-type thermocouple;

[0018] When the wall temperature is expected to be within 2000K, choose type B thermocouple.

[0019] Optionally, in step 1, a pre-buried thermocouple protection sleeve is selected according to the expected wall temperature, specifically:

[0020] When the wall temperature is expected to be within 1450K, choose armored filler insulation as the thermocouple protection sleeve;

[0021] When the wall temperature is expected to be above 1450K, ceramic tube insulation is selected as the thermocouple protection sleeve.

[0022] Optionally, in step 1, the diameter of the thermocouple wire and the diameter of the thermocouple protection tube are selected according to the thickness of the thermocouple protection tube and the wall of the turbine blade, specifically:

[0023] If the thermocouple protection sleeve is armored filler insulation, when the wall thickness of the turbine blade is greater than 1.5mm and less than 2mm, the thermocouple wire diameter is selected to be 0.15mm and the thermocouple armor diameter is selected to be 0.5mm; when the wall thickness of the turbine blade is greater than 2mm, the thermocouple wire diameter is selected to be 0.3mm and the thermocouple armor diameter is selected to be 0.8mm;

[0024] If the thermocouple protection sleeve is insulated by a ceramic tube, when the thickness of the turbine blade wall is greater than 2mm and less than 3mm, the thermocouple wire diameter is selected to be 0.2mm, the maximum outer diameter of the double-hole ceramic tube is 1mm, and the inner diameter is 0.3mm; when the thickness of the turbine blade wall is greater than 3mm, the thermocouple wire diameter is selected to be 0.5mm, the maximum outer diameter of the double-hole ceramic tube is 2mm, and the inner diameter is 0.6mm.

[0025] Optionally, in step 2, the limiting structure is a limiting step ring, and the diameter of the limiting step ring is smaller than the diameter of the thermocouple protection sleeve.

[0026] Optionally, in step 3, the laser power of the laser cladding technology is between 1500w and 3000w.

[0027] Optionally, in step 3, after sealing the channel opening using laser cladding technology, it also includes: removing the laser welds protruding from the surface of the turbine blades through a grinding and polishing process, and performing surface roughness fluorescence detection and edge detection on the turbine blades after pre-embedded thermocouples, and performing temperature measurement detection on the thermocouples.

[0028] The present invention also provides a thermocouple pre-embedded structure using a thermocouple pre-embedded method for monitoring the wall temperature of a turbine blade, comprising: a turbine blade, a pre-embedded thermocouple channel structure, and a thermocouple channel limiting structure;

[0029] The embedded thermocouple channel structure is arranged inside the wall surface of the turbine blade, and the two ends are connected to the temperature measurement position on the blade surface and the lower end wall of the turbine blade;

[0030] The thermocouple channel limiting structure is arranged on the inner surface of the wall of the turbine blade, corresponding to the embedded thermocouple channel structure, so as to ensure that the thermocouple temperature measurement end point can be arranged at the designated temperature measurement position.

[0031] Optionally, it also includes: a cooling hole structure arranged on the wall of the turbine blade for cooling the wall temperature of the turbine blade and a turbine blade mounting thread for mounting the turbine blade on the end face of the wheel rim hub.

[0032] It can be seen from the above technical solutions that, compared with the prior art, the present invention proposes a thermocouple pre-embedded method and pre-embedded structure for turbine blade wall temperature monitoring. By designing multiple thermocouple pre-embedded channels inside the turbine blade wall, the two ends of the channels are connected to the blade surface temperature measurement position and the lower end wall of the turbine blade, and the cooling holes are staggered and do not affect each other, and multiple limit structures are set at the corresponding positions on the inner surface of the turbine blade wall to ensure that the thermocouple temperature measurement end point can be arranged at the specified temperature measurement position. Finally, the channel opening is sealed by laser cladding technology, and the thermocouple temperature measurement end point is tightly fixed to the turbine blade surface, so as to achieve high-precision monitoring of the turbine blade wall temperature without affecting the original turbine blade profile and cooling structure, and the cost is low. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0034] Figure 1 It is a schematic diagram of the method flow of the present invention.

[0035] Figure 2 It is a schematic diagram of the thermocouple pre-buried structure of the present invention.

[0036] Figure 3 It is a vertical cross-sectional schematic diagram of the thermocouple pre-buried structure of the present invention.

[0037] Figure 4 It is a horizontal cross-sectional schematic diagram of the thermocouple pre-buried structure of the present invention.

[0038] Figure 5 It is a schematic diagram of the installation structure of the turbine blade of the present invention.

[0039] Among them, 1-turbine blade, 2-air film cooling hole structure, 3-embedded thermocouple channel structure, 4-thermocouple channel limiting structure, 5-turbine blade mounting thread, 6-hub mounting seat, 7-rim mounting seat, 8-turbine blade air inlet cavity, 9-turbine blade mounting accessories, 10-turbine blade fixing bolts. DETAILED DESCRIPTION

[0040] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0041] Embodiment 1:

[0042] Embodiment 1 of the present invention discloses a thermocouple pre-embedding method for monitoring the wall temperature of turbine blades, such as Figure 1 As shown, including:

[0043] Step 1: Determine the expected wall temperature of the turbine blade according to the metal material used and the cooling hole structure of the turbine blade, and select the embedded thermocouple model and thermocouple protection sleeve according to the expected wall temperature. Select the thermocouple wire diameter and thermocouple protection sleeve diameter according to the thickness of the thermocouple protection sleeve and the turbine blade wall.

[0044] According to the metal material used for the turbine blade and the cooling hole structure, the expected wall temperature of the turbine blade is determined as follows:

[0045] γ = α-β;

[0046] Among them, γ is the expected maximum wall temperature of the turbine blade; α is the maximum temperature of the metal material used while maintaining good mechanical properties; β is the temperature cooling effect provided by the cooling hole structure;

[0047] Based on the predicted maximum wall temperature γ of the turbine blade, it can be obtained that the predicted wall temperature of the turbine blade is within γ.

[0048] Select the embedded thermocouple model according to the expected wall temperature, specifically:

[0049] When the wall temperature is expected to be within 1450K, select K-type and N-type thermocouples;

[0050] When the wall temperature is expected to be within 1850K, select the S-type thermocouple;

[0051] When the wall temperature is expected to be within 2000K, choose type B thermocouple.

[0052] Select the embedded thermocouple protection sleeve according to the expected wall temperature, specifically:

[0053] Thermocouples work by requiring good insulation of the double wires (positive and negative) to avoid signal interference or short circuits. The pre-buried thermocouple method needs to consider the insulation method of the wires. The insulation methods of thermocouple double wires in common high-temperature environments are mainly divided into armored filler insulation and ceramic tube insulation. The armored filler insulation method uses high-temperature alloy materials as protective covers, which are filled with high-purity magnesium oxide powder to provide good electrical insulation and effective thermal conductivity. Its advantages are small size and certain flexibility, and it can make armored thermocouples below 0.8mm. However, its temperature resistance is limited by the melting point of high-temperature alloy materials, and its upper temperature limit is about 1450K. The ceramic tube insulation method uses high-purity aluminum oxide or magnesium oxide to make a ceramic tube as a protective cover. It has good high temperature resistance and chemical corrosion resistance, and the highest temperature resistance can reach 2000K. However, due to the characteristics of the material, the protective cover is less flexible and fragile, and the size is relatively larger than the armor.

[0054] Therefore, when the wall temperature is expected to be within 1450K, armored filler insulation is selected as the thermocouple protection sleeve; when the wall temperature is expected to be above 1450K, ceramic tube insulation is selected as the thermocouple protection sleeve.

[0055] According to the thickness of the thermocouple protection tube and the turbine blade wall, select the diameter of the thermocouple wire and the thermocouple protection tube, specifically:

[0056] If the thermocouple protection sleeve is armored filler insulation, when the wall thickness of the turbine blade is greater than 1.5mm and less than 2mm, the thermocouple wire diameter is selected to be 0.15mm and the thermocouple armor diameter is selected to be 0.5mm; when the wall thickness of the turbine blade is greater than 2mm, the thermocouple wire diameter is selected to be 0.3mm and the thermocouple armor diameter is selected to be 0.8mm;

[0057] If the thermocouple protection sleeve is insulated by a ceramic tube, when the thickness of the turbine blade wall is greater than 2mm and less than 3mm, the thermocouple wire diameter is selected to be 0.2mm, the maximum outer diameter of the double-hole ceramic tube is 1mm, and the inner diameter is 0.3mm; when the thickness of the turbine blade wall is greater than 3mm, the thermocouple wire diameter is selected to be 0.5mm, the maximum outer diameter of the double-hole ceramic tube is 2mm, and the inner diameter is 0.6mm.

[0058] Step 2: Design multiple thermocouple pre-embedded channels inside the turbine blade wall, and set multiple limit structures at corresponding positions on the inner surface of the turbine blade wall to ensure that the thermocouple temperature measurement end points can be arranged at the specified temperature measurement positions; wherein, the two ends of the thermocouple pre-embedded channels are connected to the blade surface temperature measurement position and the lower end wall of the turbine blade, and are staggered with the cooling holes and do not affect each other.

[0059] Considering the requirement of large torque under the working environment of turbine blades, turbine blades need to maintain a certain structural strength. The existing cooling holes have a certain degree of weakening on the structural strength. Therefore, the embedded thermocouple needs to consider the structure to minimize the impact on the structural strength. Therefore, the conventional embedded thermocouple method of opening a groove on the blade surface is abandoned. When designing turbine blades, the thermocouple embedded channel is designed as an internal channel on the turbine blade wall while avoiding the cooling hole channel. The two ends are connected to the temperature measurement position on the blade surface and the lower end wall of the turbine blade, and are staggered with the cooling holes without affecting each other. This structure is conducive to reducing the impact on strength, and it is also convenient for the installation of thermocouples because of the smooth channel.

[0060] In addition, a plurality of limiting structures are arranged at corresponding positions near the inner surface of the turbine blade wall. The limiting structure is a limiting step ring with a certain thickness, and the diameter of the limiting step ring is smaller than the diameter of the thermocouple protection sleeve, so as to locate the temperature measurement end point of the thermocouple and ensure the consistency of the test conditions of the thermocouples at different positions.

[0061] The turbine blades with multiple thermocouple embedded channels inside the wall are obtained by using metal 3D printing technology through heat treatment, wire cutting, benchwork, grinding and other processes.

[0062] Step 3: Insert the thermocouple selected in step 1 through the multiple channel openings on the end surface of the turbine blade wall corresponding to the thermocouple pre-embedded channel, make the temperature measuring end point of the thermocouple against the corresponding limit structure through the thermocouple pre-embedded channel, and pile up some 3D printed metal powder GH5188 at the channel opening position, seal the channel opening using laser cladding technology, and tightly fix the thermocouple temperature measuring end point to the surface of the turbine blade to ensure the reliability of temperature measurement.

[0063] The laser power of laser cladding technology is between 1500w-3000w, which ensures that the cladding metal is in close contact with the thermocouple protection sleeve without damaging the thermocouple temperature measurement end point, thereby reducing the loss of this method.

[0064] After the channel opening is sealed using laser cladding technology, the process also includes: removing the protruding laser welding spots on the surface of the turbine blades through a grinding and polishing process, performing surface roughness fluorescence detection and edge detection on the turbine blades after pre-embedded thermocouples, and performing temperature measurement detection on the thermocouples, so as to ensure the reliable appearance accuracy of the turbine blades.

[0065] When the final turbine blade with embedded thermocouple is obtained, it can be installed on the end face of the wheel rim hub, and multiple thermocouple leads are passed through the lead channel and finally fixed to the turbine blade air inlet cavity. The lead sealing is achieved through the sealing structure to complete the installation of the turbine blade.

[0066] Embodiment 2:

[0067] Embodiment 2 of the present invention discloses a specific implementation process of a thermocouple pre-embedding method for monitoring the wall temperature of a turbine blade, as follows:

[0068] The turbine blades are made of high-temperature alloy GH5188, which can maintain good mechanical strength properties under 1350 degrees. The cooling hole diameter in the cooling hole structure is designed to be 0.6mm, which can reduce the temperature of the turbine blade wall by 250 degrees. The designed thickness of the turbine blade wall is 3.5mm. The inner diameter of the thermocouple channel is designed to be 0.75mm. The designed thickness of the limit structure is 0.3mm.

[0069] Since the expected wall temperature of the turbine blade is below 1100 degrees, a K-type thermocouple is selected along with armored filler insulation GH3039, and magnesium oxide is used as a thermally conductive filler as the thermocouple protection sleeve.

[0070] Since the thermocouple protection sleeve is insulated with armored filler and the thickness of the turbine blade wall is 3.5 mm, the diameter of the thermocouple wire is 0.3 mm and the diameter of the thermocouple armor is 0.8 mm.

[0071] Since the diameter of the thermocouple armor is 0.8mm, a limiting structure with a diameter of 0.7mm is designed.

[0072] Embodiment 3:

[0073] Embodiment 3 of the present invention discloses a thermocouple pre-embedded structure using a thermocouple pre-embedded method for monitoring the wall temperature of a turbine blade, such as Figure 2 , Figure 3 , Figure 4 As shown, it includes: a turbine blade 1, a pre-buried thermocouple channel structure 3, and a thermocouple channel limiting structure 4;

[0074] in, Figure 2 is the structural diagram of the thermocouple pre-buried structure; Figure 2 The vertical section line A in the figure is used as the reference, and the vertical section view of the thermocouple embedded structure is as follows: Figure 3 shown; Figure 2 The horizontal section line B in the figure is used as the reference, and the horizontal section view of the thermocouple embedded structure is as follows: Figure 4 shown.

[0075] The embedded thermocouple channel structure 3 is arranged inside the wall surface of the turbine blade 1, and its two ends are connected to the temperature measurement position on the blade surface and the lower end wall of the turbine blade 1;

[0076] The thermocouple channel limiting structure 4 is arranged on the inner surface of the wall of the turbine blade 1, corresponding to the embedded thermocouple channel structure 3, so as to ensure that the thermocouple temperature measurement end point can be arranged at the designated temperature measurement position.

[0077] Optionally, it also includes: a cooling hole structure 2 arranged on the wall of the turbine blade 1 for cooling the wall temperature of the turbine blade 1 and a turbine blade mounting thread 5 for mounting the turbine blade 1 on the end face of the wheel rim hub.

[0078] The installation structure of the turbine blade 1 is as follows Figure 5 As shown, in addition to the pre-embedded structure of the thermocouple on the blade wall, it also includes: a hub mounting seat 6, a rim mounting seat 7, a turbine blade air inlet cavity 8, a turbine blade mounting accessory 9, and a turbine blade fixing bolt 10.

[0079] The embodiment of the present invention discloses a thermocouple pre-embedded method and pre-embedded structure for monitoring the wall temperature of turbine blades. By designing multiple thermocouple pre-embedded channels inside the wall of turbine blades, the two ends of the channels are connected to the temperature measurement position on the blade surface and the lower end wall of the turbine blade, and the cooling holes are staggered and do not affect each other, and multiple limit structures are set at corresponding positions on the inner surface of the wall of turbine blades to ensure that the thermocouple temperature measurement end point can be arranged at the designated temperature measurement position, and finally the channel opening is sealed by laser cladding technology, and the thermocouple temperature measurement end point is tightly fixed to the surface of turbine blades, so as to achieve high-precision monitoring of the wall temperature of turbine blades without affecting the original turbine blade profile and cooling structure, and the cost is low.

[0080] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part.

[0081] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A thermocouple pre-embedding method for monitoring the wall temperature of turbine blades, characterized in that: include: Step 1: Determine the expected wall temperature of the turbine blade according to the metal material used for the turbine blade and the cooling hole structure, select the embedded thermocouple model and the thermocouple protection sleeve according to the expected wall temperature, and select the thermocouple wire diameter and the thermocouple protection sleeve diameter according to the thermocouple protection sleeve and the turbine blade wall thickness; Step 2: Design multiple thermocouple pre-buried channels inside the turbine blade wall, and set multiple limit structures at corresponding positions on the inner surface of the turbine blade wall to ensure that the thermocouple temperature measurement end points can be arranged at the specified temperature measurement positions; wherein the two ends of the thermocouple pre-buried channels are connected to the blade surface temperature measurement position and the lower end wall of the turbine blade, and are staggered with the cooling holes without affecting each other; Step 3: Insert the thermocouple selected in step 1 through a plurality of channel openings on the end surface of the turbine blade wall corresponding to the thermocouple pre-buried channel, make the temperature measuring end point of the thermocouple abut against the corresponding limiting structure through the thermocouple pre-buried channel, and seal the channel opening using laser cladding technology to tightly fix the temperature measuring end point of the thermocouple to the surface of the turbine blade.

2. A thermocouple pre-embedding method for turbine blade wall temperature monitoring according to claim 1, characterized in that: In step 1, the expected wall temperature of the turbine blade is determined according to the metal material used for the turbine blade and the cooling hole structure, specifically: γ = α-β; Among them, γ is the expected maximum wall temperature of the turbine blade; α is the maximum temperature of the metal material used while maintaining good mechanical properties; β is the temperature cooling effect provided by the cooling hole structure; Based on the predicted maximum wall temperature γ of the turbine blade, it can be obtained that the predicted wall temperature of the turbine blade is within γ.

3. A thermocouple pre-embedding method for turbine blade wall temperature monitoring according to claim 1, characterized in that: In step 1, the pre-buried thermocouple model is selected according to the expected wall temperature, specifically: When the expected wall temperature is within 1450K, K-type and N-type thermocouples are selected; When the expected wall temperature is within 1850K, select the S-type thermocouple; When the expected wall temperature is within 2000K, a type B thermocouple is selected.

4. A thermocouple pre-embedding method for monitoring the wall temperature of turbine blades according to claim 1, characterized in that: In step 1, the pre-buried thermocouple protection sleeve is selected according to the expected wall temperature, specifically: When the expected wall temperature is within 1450K, armored filler insulation is selected as the thermocouple protection sleeve; When the expected wall temperature is above 1450K, ceramic tube insulation is selected as the thermocouple protection sleeve.

5. A thermocouple pre-embedding method for turbine blade wall temperature monitoring according to claim 4, characterized in that: In step 1, the diameter of the thermocouple wire and the diameter of the thermocouple protection tube are selected according to the thickness of the thermocouple protection tube and the turbine blade wall, specifically: If the thermocouple protection sleeve is armored filler insulation, when the wall thickness of the turbine blade is greater than 1.5mm and less than 2mm, the thermocouple wire diameter is selected to be 0.15mm and the thermocouple armor diameter is selected to be 0.5mm; when the wall thickness of the turbine blade is greater than 2mm, the thermocouple wire diameter is selected to be 0.3mm and the thermocouple armor diameter is selected to be 0.8mm; If the thermocouple protection sleeve is insulated by a ceramic tube, when the wall thickness of the turbine blade is greater than 2mm and less than 3mm, the diameter of the thermocouple wire is selected to be 0.2mm, the maximum outer diameter of the double-hole ceramic tube is 1mm, and the inner diameter is 0.3mm; when the wall thickness of the turbine blade is greater than 3mm, the diameter of the thermocouple wire is selected to be 0.5mm, the maximum outer diameter of the double-hole ceramic tube is 2mm, and the inner diameter is 0.6mm.

6. A thermocouple pre-embedding method for turbine blade wall temperature monitoring according to claim 1, characterized in that: In step 2, the limiting structure is a limiting step ring, and the diameter of the limiting step ring is smaller than the diameter of the thermocouple protection sleeve.

7. A thermocouple pre-embedding method for monitoring the wall temperature of turbine blades according to claim 1, characterized in that: In step 3, the laser power of the laser cladding technology is between 1500w and 3000w.

8. The method for pre-embedding thermocouples for monitoring the wall temperature of turbine blades according to claim 1, characterized in that: In step 3, after the channel opening is sealed by laser cladding technology, it also includes: removing the laser welding points protruding from the surface of the turbine blade by a grinding and polishing process, and performing surface roughness fluorescence detection and edge detection on the turbine blade after pre-embedded thermocouples, and performing temperature measurement detection on the thermocouples.

9. A thermocouple pre-embedded structure using a thermocouple pre-embedded method for monitoring the wall temperature of a turbine blade according to any one of claims 1 to 8, characterized in that: include: Turbine blades, embedded thermocouple channel structure, thermocouple channel limit structure; The embedded thermocouple channel structure is arranged inside the wall surface of the turbine blade, and the two ends are connected to the temperature measurement position on the blade surface and the lower end wall of the turbine blade; The thermocouple channel limiting structure is arranged on the inner surface of the wall of the turbine blade, corresponding to the embedded thermocouple channel structure, so as to ensure that the thermocouple temperature measurement end point can be arranged at the designated temperature measurement position.

10. A thermocouple embedded structure according to claim 9, characterized in that: Also includes: A cooling hole structure is arranged on the wall surface of the turbine blade for cooling the wall surface temperature of the turbine blade, and a turbine blade mounting thread is used to mount the turbine blade on the end surface of the wheel rim hub.

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