A design method for a heat-bending resistant drum rotor with a high thermal conductivity plating or coating

Abstract

The present application belongs to the field of aero-engine design, and is a method for designing a heat-bending-resistant drum rotor with a high-thermal-conductivity plating or coating. The method first obtains the structural parameters and thermal conductivity coefficient of the rotor shaft segment, and collects the thermal bending parameters of the corresponding rotor shaft segment after shutdown; then selects the thermal conductive material and the use position of the thermal conductive material on the rotor shaft segment, calculates the coating parameters, and applies the thermal conductive material to the rotor shaft segment; sets a thermal conductivity improvement coefficient threshold, and determines whether the thermal conductivity improvement coefficients in the two cases meet the thermal conductivity improvement coefficient threshold. If so, the design is completed; the demand for the damping device is reduced. If there are no other vibration problems, the damping device can be eliminated to reduce the structural complexity and weight.

Description

Technical Field

[0001] The present application belongs to the field of aero-engine design, and in particular relates to a design method for a heat-resistant bending drum rotor with a high thermal conductivity plating or coating. Background Art

[0002] After a period of operation and shutdown, turbojet and turbofan engines dissipate heat to the environment primarily through conduction and natural convection. Within the rotor disc cavity, hot air rises and cold air sinks, resulting in a slow heat dissipation process. This can easily lead to "thermal buckling," where the upper rotor components experience higher temperatures and greater thermal deformation than the lower. This buckling increases rotor imbalance, leading to excessive vibration and increased rotor-stator wear, which in turn impacts engine reliability and performance retention. This buckling typically occurs within half an hour of engine shutdown and can persist for several hours. The time between landing and takeoff is typically 0.5 to 1.5 hours, which is when the buckling is most pronounced. Therefore, this buckling significantly impacts the engine's re-deployment efficiency. Similar rotor buckling after shutdown also occurs in gas turbines, hindering restarts.

[0003] Currently, there are no structural measures in engine design to directly suppress or alleviate the degree of rotor "thermal bending". Generally, the vibration amplitude caused by "thermal bending" is suppressed by setting a damping vibration reduction device.

[0004] When using a damping device:

[0005] 1. The damping vibration reduction device increases the structural complexity and weight, and its function is to reduce vibration rather than alleviate or suppress the rotor imbalance caused by "thermal bending", which only treats the symptoms but not the root cause;

[0006] 2. Damping devices are designed specifically for a normal rotor imbalance range. However, the imbalance caused by thermal bending is typically significantly greater than this normal imbalance range. When the imbalance exceeds the designed range, the damping device loses its effectiveness or exhibits strong nonlinear characteristics, leading to rotor dynamic instability.

[0007] For engines without damping and vibration reduction devices, additional usage restrictions are needed to ensure safe engine starting, such as cold running before starting (the starter rotates but does not spray fuel into the combustion chamber for ignition) to promote uniform temperature of the rotor and disc cavity and alleviate "thermal bending" deformation.

[0008] When using restrictions:

[0009] 1. When the "cold operation" operating condition is added, the starter life is increased;

[0010] 2. The starting time is still longer than the normal starting time, which affects the efficiency of the next deployment.

[0011] Therefore, how to ensure the stability of the engine and the life of the starter while reducing the thermal bending of the engine is a problem that needs to be solved. Summary of the Invention

[0012] The purpose of this application is to provide a design method for a heat-bending resistant drum rotor with a high thermal conductivity plating or coating to solve the problem in the prior art that it is difficult to ensure the stability of the engine or the life of the starter while reducing the thermal bending of the engine.

[0013] The technical solution of this application is: a method for designing a heat-bending resistant drum rotor with a high thermal conductivity plating or coating, comprising:

[0014] Determine the rotor shaft segment that needs to be subjected to heat-resistant bending in a high-temperature environment according to the current engine type, and obtain the structural parameters and thermal conductivity of the rotor shaft segment;

[0015] According to the structural parameters and thermal conductivity of the current rotor shaft segment, a thermal conductive material and a location for use of the thermal conductive material on the rotor shaft segment are selected, coating parameters are calculated, and the thermal conductive material is coated on the rotor shaft segment;

[0016] A thermal conductivity improvement coefficient threshold is set to determine whether the thermal conductivity improvement coefficients in the two cases meet the thermal conductivity improvement coefficient threshold. If so, the design is completed; if not, the thermal conductive material and usage location applied on the rotor shaft segment are reselected, and the coating parameters are recalculated.

[0017] Preferably, the coating parameters include coating thickness, and the calculation formula of the coating thickness is:

[0018]

[0019] Where λ b is the thermal conductivity of the corresponding rotor shaft section, t b is the substrate thickness, λ c is the thermal conductivity of the coating / plating material in the plane, and n is the improvement coefficient of the circumferential thermal conductivity after adding the coating / plating.

[0020] Preferably, when the rotor shaft segment is plated with a thermally conductive material, the thermally conductive material selected is metal copper or silver; when the rotor shaft segment is coated with a thermally conductive material, the thermally conductive material selected is a graphite film or a graphene film.

[0021] Preferably, the rotor shaft section subjected to thermal bending resistance is a drum shaft.

[0022] Preferably, the location where the heat conductive material is applied to the rotor shaft segment includes the inner surface, outer surface or both sides of the rotor.

[0023] The present application discloses a method for designing a heat-resistant, bending-resistant drum rotor with a high-thermal-conductivity plating or coating. The method first obtains the structural parameters and thermal conductivity of the rotor shaft segment, then selects the thermally conductive material and its location on the rotor shaft segment, calculates the coating parameters, and applies the thermally conductive material to the rotor shaft segment. A thermal conductivity enhancement threshold is set to determine whether the thermal conductivity enhancement coefficients under the two engine whole-machine tests meet the threshold. If so, the design is complete. This method reduces the need for damping devices; if there are no other vibration issues, the damping device can be eliminated to reduce structural complexity and weight. Additional operating conditions such as cold operation are not required, which reduces starter life and improves engine re-start efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions provided by this application, the following is a brief introduction to the accompanying drawings. Obviously, the accompanying drawings described below are only some embodiments of this application.

[0025] Figure 1 This is a schematic diagram of the overall process of this application;

[0026] Figure 2 A schematic diagram of the structure for adding a coating / plating layer to the inner surface of the rotor in this application;

[0027] Figure 3 A schematic diagram of the structure for adding a coating / plating layer to the outer surface of the rotor in this application;

[0028] Figure 4 This is a schematic diagram of the structure of adding coating / plating on both sides of the rotor surface in this application. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solutions and advantages of the implementation of this application clearer, the technical solutions in the embodiments of this application will be described in more detail below in conjunction with the drawings in the embodiments of this application.

[0030] A method for designing a drum rotor with a high thermal conductivity plating or coating to resist thermal bending, such as Figure 1 As shown, the following steps are included:

[0031] Step S100, determining a rotor shaft segment that needs to be subjected to heat-resistant bending in a high-temperature environment according to the current engine type, and obtaining structural parameters and thermal conductivity of the rotor shaft segment;

[0032] Preferably, a rotor shaft section that is resistant to thermal bending is selected as the drum shaft of the high-pressure rotor. The drum shaft is made of high-temperature alloy material with a thermal conductivity coefficient of the order of 10 to 20 (W / (mK)). The thermal bending parameters include rotor imbalance, thermal conductivity, vibration amplitude, etc.

[0033] Step S200, selecting a thermal conductive material and a location for the thermal conductive material on the rotor shaft segment based on the structural parameters and thermal conductivity of the current rotor shaft segment, calculating coating parameters, and coating the thermal conductive material on the rotor shaft segment;

[0034] Preferably, when the rotor shaft segment is plated with a thermally conductive material, the thermally conductive material selected is metal copper or silver (with a thermal conductivity of the order of 400W / (mK)), and a coating is formed after plating; when the rotor shaft segment is coated with a thermally conductive material, the thermally conductive material selected is graphite film or graphene film (with a thermal conductivity of the order of 1000-2000W / (mK) or even higher), and a coating is formed after coating; the coating method can be any existing method, and the details will not be repeated here.

[0035] The coating parameters include coating thickness, which is calculated as follows:

[0036]

[0037] Where λ b is the thermal conductivity of the corresponding rotor shaft section, t b is the substrate thickness, λ c is the thermal conductivity of the coating / plating material in the plane, and n is the improvement coefficient of the circumferential thermal conductivity after adding the coating / plating.

[0038] Step S300, setting a thermal conductivity improvement coefficient threshold, and determining whether the thermal conductivity improvement coefficients in the two cases meet the thermal conductivity improvement coefficient threshold. If so, the design is completed; if not, the thermal conductive material and usage location applied to the rotor shaft segment are reselected, and the coating parameters are recalculated.

[0039] Preferably, the location where the heat conductive material is applied to the rotor shaft segment includes the inner surface of the rotor (such as Figure 2 As shown in ①), the outer surface (as shown in Figure 3 ② in the middle) or on both sides (as shown in Figure 4 According to different thermal conductivity requirements, different coating methods can be selected.

[0040] If the thermal conductivity improvement coefficient does not meet the requirements, a thermally conductive material with stronger thermal conductivity should be selected, such as changing from metal coating to graphite film coating, or increasing the thickness of the plating or coating, or changing from single-layer coating to double-sided surface coating, etc., and the selection should be made according to actual needs.

[0041] Taking the example of increasing the circumferential heat conduction capacity of GH4169 drum shaft with a wall thickness of 3mm to 2 times, the required thickness of the silver coating is

[0042]

[0043] In order to reduce the difficulty of the plating process, double-sided plating is adopted, and the thickness of a single layer is 0.075mm.

[0044] If graphite film / graphene film is used, the required coating thickness is

[0045]

[0046] This application first obtains the structural parameters and thermal conductivity of the rotor shaft segment, then selects the thermal conductive material and the use position of the thermal conductive material on the rotor shaft segment, calculates the coating parameters, and applies the thermal conductive material to the rotor shaft segment; sets a thermal conductivity improvement coefficient threshold, determines whether the thermal conductivity improvement coefficients in the two cases meet the thermal conductivity improvement coefficient threshold, and if so, completes the design. The demand for damping devices is reduced. If there are no other vibration problems, the damping device can be eliminated to reduce structural complexity and weight; no additional use conditions such as cold operation are required, which saves the life of the starter and improves the engine's re-deployment efficiency. At the same time, it can improve its circumferential and axial thermal conductivity, reduce the circumferential temperature difference and deformation difference under natural convection conditions after parking, and suppress rotor thermal bending to reduce the workload and preparation cycle of hot start preparation. This technical measure has the effect of reducing structural thermal stress.

[0047] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of the present application. Therefore, the scope of protection of the present application should be based on the scope of protection of the claims.

Claims

1. A method for designing a heat-bending resistant drum rotor with a high thermal conductivity plating or coating, characterized in that: include: Determine the rotor shaft segment that needs to be subjected to heat-resistant bending in a high-temperature environment according to the current engine type, and obtain the structural parameters and thermal conductivity of the rotor shaft segment; According to the structural parameters and thermal conductivity of the current rotor shaft segment, a thermal conductive material and a location for use of the thermal conductive material on the rotor shaft segment are selected, coating parameters are calculated, and the thermal conductive material is coated on the rotor shaft segment; Set a thermal conductivity improvement coefficient threshold, and determine whether the thermal conductivity improvement coefficient meets the thermal conductivity improvement coefficient threshold. If so, complete the design. If not, reselect the thermal conductive material and application location to be applied on the rotor shaft segment, and recalculate the application parameters; The coating parameters include coating thickness, and the calculation formula of the coating thickness is: Where λ b is the thermal conductivity of the corresponding rotor shaft section, t b is the substrate thickness, λ c is the thermal conductivity of the coating / plating material in the plane, and n is the improvement coefficient of the circumferential thermal conductivity after adding the coating / plating.

2. The method for designing a heat-bending resistant drum rotor with a high thermal conductivity plating or coating according to claim 1, wherein: When the rotor shaft segment is plated with a thermally conductive material, the selected thermally conductive material is metal copper or silver; when the rotor shaft segment is coated with a thermally conductive material, the selected thermally conductive material is a graphite film or a graphene film.

3. The method for designing a heat-bending resistant drum rotor with a high thermal conductivity plating or coating according to claim 1, wherein: The rotor shaft section that is subjected to thermal bending resistance is the drum shaft.

4. The method for designing a heat-bending resistant drum rotor with a high thermal conductivity plating or coating according to claim 1, wherein: The locations where the rotor shaft segment is coated with the heat conductive material include the inner surface, outer surface or both sides of the rotor.

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