Method for installing thermocouple for measuring metal temperature of rotor wheel disc of heavy-duty gas turbine

Abstract

The invention discloses a thermocouple installation method for measuring the metal temperature of a rotor wheel disc of a heavy-duty gas turbine. The thermocouple installation method comprises the steps that a temperature measurement blind hole is machined in the surface of a rotor wheel disc of the heavy duty gas turbine, the machining depth of the temperature measurement blind hole is Xmm, and the machining depth of the temperature measurement blind hole is determined according to the distance between the hole opening position and the target measurement position; preparing a temperature measuring head comprising a fine thermocouple hot node, a metal cap and a high-temperature solder; the temperature measuring head is installed in the temperature measuring blind hole, and the residual space in the temperature measuring blind hole is filled with dissolvable heat-conducting high-temperature glue; and blocking the orifice of the temperature measuring blind hole by using a fixing sheet. According to the invention, the problem of high processing difficulty caused by a slender temperature measurement blind hole and the problem of difficulty in keeping contact with the hole wall caused by the characteristics of flexibility of a fine thermocouple and too small size of a temperature measurement node are solved, and the problem of local metal temperature field change caused by additional thermal resistance introduced by hole opening is relieved; and meanwhile, the device has the advantages of preventing the risk of redundant substances in the disc cavity and being easy to disassemble and maintain.

Description

Technical Field

[0001] The invention relates to the technical field of heavy-duty gas turbines, and in particular to a thermocouple installation method for measuring the metal temperature of a heavy-duty gas turbine rotor disc. Background Art

[0002] As a core component of a heavy-duty gas turbine, the rotor's lifespan and operational reliability are directly linked to the turbine's operational safety. One of the primary factors influencing rotor lifespan and reliability is the rotor's metal temperature and its evolution. Most current mainstream heavy-duty gas turbine models utilize a disc-type tie-rod rotor structure. This complex structure of the rotor disc cavity and internal cooling flow paths makes simulation and prediction of the transient metal temperature field extremely challenging.

[0003] Therefore, during the forward R&D process, it is necessary to monitor the metal temperature at some key positions inside the rotor during the first prototype operation test, verify the reliability of the transient metal temperature field simulation prediction results through test data, and then verify the design input of the rotor structural integrity design, providing support for the evaluation of rotor strength, life analysis and evaluation, etc.

[0004] However, since the disc-type pull-rod structure rotor of the heavy-duty gas turbine has the characteristics of large radial size of the wheel disc, small space in the disc cavity, and irregular shape, it is always in a complex environment of high temperature, high-speed rotation, and vibration during operation, and the metal temperature measurement method of the relevant technology is not applicable. Summary of the Invention

[0005] The present invention is based on the inventor's discovery and understanding of the following facts and problems:

[0006] In related art, the method for measuring the internal temperature of metal is to machine a temperature-measuring blind hole of a certain depth on the metal surface, insert a thermocouple into the blind hole, and secure it. However, this method is not suitable for measuring the metal temperature inside the rotor disc for the following reasons. First, when the measurement position is close to the inside of the disc, the processing depth of the temperature-measuring blind hole is relatively large. If a small aperture is used, there is a risk of the drill bit breaking, and the processing is difficult. If a large aperture or a stepped hole is used, it is difficult to reliably secure the thermocouple in the blind hole when the rotor rotates and vibrates. At the same time, the larger aperture introduces additional thermal resistance, affecting the temperature distribution of the disc metal. Second, due to the small space inside the rotor disc cavity, the thermocouple needs to be bent when securing it. Conventional armored thermocouples are too rigid and not suitable. Although micro thermocouples are easy to secure, due to their inherent flexibility and small thermal node size, they are difficult to maintain contact with the hole wall in the blind hole when the rotor rotates and vibrates, resulting in unreliable measurement results.

[0007] The present invention aims to solve one of the technical problems in the related art at least to a certain extent.

[0008] To this end, an embodiment of the present invention provides a thermocouple installation method for measuring the metal temperature of a heavy-duty gas turbine rotor disc. The thermocouple installation method has the advantages of low processing difficulty and reliable measurement results.

[0009] The thermocouple installation method for measuring the metal temperature of a heavy-duty gas turbine rotor disc according to an embodiment of the present invention includes:

[0010] Processing a temperature measuring blind hole on the surface of a heavy-duty gas turbine rotor disc, wherein the processing depth of the temperature measuring blind hole is X mm, and the processing depth of the temperature measuring blind hole is determined according to the distance between the hole position and the target measurement position;

[0011] Prepare a temperature measuring head including a fine thermocouple hot node, a metal cap and high-temperature solder;

[0012] Install the temperature measuring head in the temperature measuring blind hole, and fill the remaining space in the temperature measuring blind hole with soluble thermally conductive high-temperature glue;

[0013] A fixing plate is used to seal the opening of the temperature measuring blind hole.

[0014] The thermocouple installation method for measuring the metal temperature of a heavy-duty gas turbine rotor disc according to an embodiment of the present invention solves the problem of difficulty in processing caused by slender temperature measurement blind holes and the problem of difficulty in maintaining contact with the hole wall due to the flexibility of the micro thermocouple and the small size of the temperature measurement node. It alleviates the problem of changes in the local metal temperature field caused by additional thermal resistance introduced by the opening, and at the same time has the advantages of preventing the risk of excess objects in the disc cavity and easy disassembly and maintenance.

[0015] In some embodiments, the processing direction of the temperature measuring blind hole points from the low radius side to the high radius side of the wheel disc.

[0016] In some embodiments, the opening of the temperature measuring blind hole is chamfered.

[0017] In some embodiments, the preparation process of the temperature measuring head includes:

[0018] processing the metal cap;

[0019] Filling the metal cap with high-temperature solder, and inserting the micro-thermocouple hot node into the molten high-temperature solder, so that the micro-thermocouple hot node contacts the inner wall of the metal cap;

[0020] The temperature measuring head is formed after the high-temperature solder is cooled and solidified.

[0021] In some embodiments, the outer diameter of the metal cap is (D1-2Y) mm, the diameter of the temperature measuring blind hole is D1 mm, the radial single-side gap reserved in the temperature measuring blind hole is Y mm, and the inner diameter of the metal cap is larger than the size of the micro-thermocouple thermal node.

[0022] In some embodiments, the radial single-edge clearance is determined based on a difference in thermal expansion between the metal cap and the heavy-duty gas turbine rotor disk.

[0023] In some embodiments, before the temperature measuring head is installed in the temperature measuring blind hole, the outer surface of the temperature measuring head is ground.

[0024] In some embodiments, the thermal conductivity coefficient of the soluble thermally conductive high-temperature adhesive filled in the temperature measurement blind hole deviates from the thermal conductivity coefficient of the rotor disk by ≤5%.

[0025] In some embodiments, the fixing plate has a protrusion. After the fixing plate blocks the opening of the temperature measurement blind hole, the lead wire of the micro-thermocouple hot node is led out through the gap between the protrusion and the opening.

[0026] In some embodiments, the leads of the micro-thermocouple hot node are fixed on the surface of the wheel in a serpentine path. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic diagram of machining temperature measurement blind holes in a heavy-duty gas turbine rotor disk according to an embodiment of the present invention.

[0028] Figure 2 yes Figure 1 Enlarged schematic diagram of part A.

[0029] Figure 3 Schematic diagram of a temperature measuring head according to an embodiment of the present invention.

[0030] Figure 4 1 is a first schematic diagram of a fixing plate according to an embodiment of the present invention.

[0031] Figure 5 2 is a second schematic diagram of a fixing plate according to an embodiment of the present invention.

[0032] Figure 6 The figure is a schematic diagram of the installation of thermocouples for measuring the metal temperature of a heavy-duty gas turbine rotor disc according to an embodiment of the present invention.

[0033] Figure 7 yes Figure 6 Schematic diagram of the enlarged portion B.

[0034] Figure 8 yes Figure 6 Enlarged schematic diagram of part C.

[0035] Reference numerals:

[0036] 1-Heavy-duty gas turbine rotor disc, 101-Low radius side, 102-High radius side, 2-Temperature measurement blind hole, 3-Micro thermocouple hot node, 4-Metal cap, 5-High temperature solder, 6-Temperature measurement head, 7-Soluble thermally conductive high temperature adhesive, 8-Fixer. DETAILED DESCRIPTION

[0037] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to be used to explain the present invention, but should not be understood as limiting the present invention.

[0038] The following describes a method for installing a thermocouple for measuring the metal temperature of a heavy-duty gas turbine rotor disk according to an embodiment of the present invention with reference to the accompanying drawings.

[0039] like Figure 1-8 As shown, the thermocouple installation method for measuring the metal temperature of a heavy-duty gas turbine rotor disc according to an embodiment of the present invention includes:

[0040] S1, according to the measurement requirements, first process the temperature measuring blind hole 2 at a position that is easy to process on the surface of the heavy-duty gas turbine rotor disc 1 to reduce the difficulty of machining. The processing depth of the temperature measuring blind hole 2 is Xmm, and the processing depth of the temperature measuring blind hole 2 is D1mm. Among them, the opening direction of the temperature measuring blind hole 2 points from the low radius side 101 of the disc (the side close to the disc center) to the high radius side 102 (the side close to the wheel rim). The processing depth of the temperature measuring blind hole 2 is determined according to the distance between the hole position and the target measurement position. The diameter of the temperature measuring blind hole 2 is selected based on the hole depth. The size that is easy to process is selected. In addition, the hole of the temperature measuring blind hole 2 is chamfered to prevent sharp edges from cutting the thermocouple leads.

[0041] S2, prepare a temperature measuring head 6 comprising a fine thermocouple hot node 3, a metal cap 4, and high-temperature solder 5, while ensuring heat transfer while increasing the size and mass of the hot node. The centrifugal load generated by the rotation of the wheel ensures that the temperature measuring head 6 contacts the hole wall of the temperature measuring blind hole 2. The preparation steps include:

[0042] Process the metal cap 4, select the material of the metal cap 4 according to the metal temperature prediction result at the measurement position, and determine the radial single-sided gap Y mm reserved in the temperature measurement blind hole 2 according to the difference in thermal expansion between the metal cap 4 and the heavy-duty gas turbine rotor disk 1. Then, the outer diameter of the metal cap 4 is (D1-2Y) mm, and the inner diameter of the metal cap 4 is larger than the size of the micro-thermocouple hot node 3.

[0043] In the cold state, a small gap is reserved in the radial direction between the temperature measuring head 6 and the temperature measuring blind hole 2 to facilitate the exhaust of air during installation and provide space for the thermal expansion of the temperature measuring head 6 and the wheel.

[0044] Considering that the measurement position is located inside the rotor and the space is small, a micro thermocouple is selected as the temperature sensor. When making the hot node, pay attention to making the exposed thermocouple wire as short as possible.

[0045] High-temperature solder 5 is filled into the metal cap 4, and at the same time, the micro-thermocouple hot node 3 is inserted into the molten high-temperature solder 5. The material of the high-temperature solder 5 is determined by the metal temperature prediction result at the measurement position. The micro-thermocouple hot node 3 contacts the inner wall of the metal cap 4, and the temperature measuring head 6 is formed after the high-temperature solder 5 cools and solidifies.

[0046] Carry out trial assembly and grind the outer surface of the temperature measuring head 6 according to the actual assembly situation to ensure reliable installation.

[0047] S3, insert the temperature measuring head 6 into the temperature measuring blind hole 2 and press it against the bottom of the temperature measuring blind hole 2, then select a soluble thermally conductive high-temperature glue 7 whose thermal conductivity is as close as possible to the thermal conductivity of the wheel disc material, that is, the thermal conductivity of the soluble thermally conductive high-temperature glue 7 filled in the temperature measuring blind hole 2 deviates from the thermal conductivity of the rotor wheel disc by ≤5%, and the remaining space in the temperature measuring blind hole 2 is tightly filled with the soluble thermally conductive high-temperature glue 7.

[0048] S4: Use a fixing plate 8 to seal the opening of the temperature-measuring blind hole 2 by spot welding. Fixing plate 8 has a raised portion. After sealing the opening of the temperature-measuring blind hole 2, the leads of the micro-thermocouple hot junction 3 can be routed through the gap between the raised portion and the opening. Furthermore, the leads of the micro-thermocouple hot junction 3 are fixed in a serpentine path on the surface of the wheel disc, alleviating lead tension caused by wheel disc expansion and deformation during the test.

[0049] The remaining space in the blind hole is sealed with a soluble thermally conductive high-temperature glue 7 whose thermal conductivity is close to that of the wheel material, and a fixing piece 8 is spot-welded at the hole mouth, thereby alleviating the problem of the local metal temperature field change caused by the additional thermal resistance introduced by the opening, while also having the advantages of preventing the risk of excess objects in the disk cavity and easy disassembly and maintenance.

[0050] In summary, the thermocouple installation method for measuring the metal temperature of a heavy-duty gas turbine rotor disc according to the embodiment of the present invention solves the problem of difficulty in processing caused by slender temperature measurement blind holes and the problem of difficulty in maintaining contact with the hole wall due to the flexibility of the micro thermocouple and the small size of the temperature measurement node. It alleviates the problem of changes in the local metal temperature field caused by additional thermal resistance introduced by the opening, and at the same time has the advantages of preventing the risk of excess objects in the disc cavity and easy disassembly and maintenance.

[0051] Since the radial dimension of the temperature measuring head 6 made of the metal cap 4 is much larger than the micro-thermocouple hot node 3 and is sealed with a soluble thermally conductive high-temperature glue 7, the diameter of the temperature measuring blind hole 2 can be selected to a suitable processing size according to the hole depth, solving the problem of difficulty in machining slender blind holes.

[0052] The temperature measuring head 6 has a large mass, and the centrifugal load generated when the wheel test piece rotates can be used to ensure that the temperature measuring head 6 maintains contact with the wall of the temperature measuring blind hole 2, solving the problem that the micro thermocouple is difficult to maintain contact with the hole wall due to its own flexibility and small head size.

[0053] In the cold state, the outer diameter of the temperature measuring head 6 is slightly smaller than the diameter of the temperature measuring blind hole 2, which is convenient for exhausting air during installation and provides space for thermal expansion of the temperature measuring head 6 and the wheel.

[0054] The remaining space in the blind hole is filled with soluble thermally conductive high-temperature glue 7 and sealed with a spot-welded fixing piece 8 at the hole mouth, which strengthens the close contact between the temperature measuring head 6 and the wall of the blind hole, and also prevents the risk of the temperature measuring head 6 falling out of the blind hole.

[0055] The thermal conductivity of the soluble thermally conductive high-temperature adhesive 7 is close to that of the wheel material, which alleviates the problem of changes in the local metal temperature field caused by the additional thermal resistance introduced by the opening.

[0056] When the wheel disc test piece rotates, the fixing piece 8 is pressed against the surface of the test piece by the centrifugal load, thereby preventing the risk of excess matter in the disc cavity caused by the fixing piece 8 falling off.

[0057] When there is a need to repair or replace the thermocouple, the fixing plate 8 can be removed and the thermally conductive high-temperature glue can be dissolved with a specific solvent, and then the temperature measuring head 6 can be directly pulled out to facilitate product maintenance.

[0058] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0059] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0060] In the present invention, unless otherwise specified or limited, the terms "installed," "connected," "connect," "fixed," etc. should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integration; mechanical connection, electrical connection, or communication; direct connection or indirect connection through an intermediate medium; internal communication between two elements or interaction between two elements, unless otherwise specified. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0061] In the present invention, unless otherwise expressly specified or limited, when a first feature is "above" or "below" a second feature, it may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediary. Furthermore, when a first feature is "above," "above," or "above" a second feature, it may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. When a first feature is "below," "below," or "below" a second feature, it may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0062] In the present invention, the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and the features of different embodiments or examples without contradiction.

[0063] Although the embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A thermocouple installation method for measuring the metal temperature of a heavy-duty gas turbine rotor disc, characterized in that: include: Processing a temperature measuring blind hole on the surface of a heavy-duty gas turbine rotor disc, wherein the processing depth of the temperature measuring blind hole is X mm, and the processing depth of the temperature measuring blind hole is determined according to the distance between the hole position and the target measurement position; Prepare a temperature measuring head including a fine thermocouple hot node, a metal cap and high-temperature solder; Install the temperature measuring head in the temperature measuring blind hole, and fill the remaining space in the temperature measuring blind hole with soluble thermally conductive high-temperature glue; A fixing plate is used to seal the opening of the temperature measuring blind hole.

2. The thermocouple installation method for measuring the metal temperature of a heavy-duty gas turbine rotor disc according to claim 1 is characterized in that: The processing direction of the temperature measuring blind hole is from the low radius side to the high radius side of the wheel disc.

3. The thermocouple installation method for measuring the metal temperature of a heavy-duty gas turbine rotor disc according to claim 1, characterized in that: The opening of the temperature measuring blind hole is chamfered.

4. The method for installing a thermocouple for measuring the metal temperature of a heavy-duty gas turbine rotor disc according to claim 1, characterized in that: The preparation process of the temperature measuring head includes: processing the metal cap; Filling the metal cap with high-temperature solder, and inserting the micro-thermocouple hot node into the molten high-temperature solder, so that the micro-thermocouple hot node contacts the inner wall of the metal cap; The temperature measuring head is formed after the high-temperature solder is cooled and solidified.

5. The method for installing a thermocouple for measuring the metal temperature of a heavy-duty gas turbine rotor disc according to claim 4, characterized in that: The outer diameter of the metal cap is (D1-2Y) mm, the diameter of the temperature measuring blind hole is D1 mm, the radial single-side gap reserved in the temperature measuring blind hole is Y mm, and the inner diameter of the metal cap is larger than the size of the micro-thermocouple thermal node.

6. The method for installing a thermocouple for measuring the metal temperature of a heavy-duty gas turbine rotor disc according to claim 5, characterized in that: The radial single-side clearance is determined according to the difference in thermal expansion between the metal cap and the heavy-duty gas turbine rotor disk.

7. The method for installing a thermocouple for measuring the metal temperature of a heavy-duty gas turbine rotor disc according to claim 1, characterized in that: Before the temperature measuring head is installed in the temperature measuring blind hole, the outer surface of the temperature measuring head is ground.

8. The method for installing a thermocouple for measuring the metal temperature of a heavy-duty gas turbine rotor disc according to claim 1, characterized in that: The deviation between the thermal conductivity coefficient of the soluble heat-conductive high-temperature glue filled in the temperature-measuring blind hole and the thermal conductivity coefficient of the rotor wheel disc is ≤5%.

9. The method for installing a thermocouple for measuring the metal temperature of a heavy-duty gas turbine rotor disc according to claim 1, characterized in that: The fixing plate has a protrusion. After the fixing plate blocks the opening of the temperature measurement blind hole, the lead wire of the micro thermocouple hot node is led out through the gap between the protrusion and the opening.

10. The method for installing a thermocouple for measuring the metal temperature of a heavy-duty gas turbine rotor disc according to claim 1, characterized in that: The leads of the micro-thermocouple hot nodes are fixed on the surface of the wheel disc in a serpentine path.

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