Electric control oil injection simulation multi-layer thermal barrier coating oil mist erosion test system and method

Abstract

The invention relates to a test system and method for simulating oil mist erosion of a multi-layer thermal barrier coating through electronic control oil injection. The system comprises a fuel supply unit, an electric control fuel injection simulation device, an erosion cavity, a damage monitoring device, a controller, a pressure sensor, an acoustic emission AE sensor, a sliding rail height adjusting mechanism and the like. During testing, one or more multi-layer thermal barrier coating samples are fixed in an erosion cavity, then fuel oil is injected to the samples through an electric control oil injection simulation device, and the mass change, the surface appearance change, the denudation area change and the acoustic emission characteristic quantity change of the samples are collected through a damage monitoring device, an acoustic emission AE sensor and the like; therefore, various properties of the multi-layer thermal barrier coating attached to the surface of the sample are evaluated. The whole testing process is precisely regulated and controlled through the oil injection pressure closed-loop control loop and the damage closed-loop control loop, and the device has the advantages of being accurate and reliable in result, good in repeatability and the like and can be used for systematic evaluation of overall and layered damage characteristics of the multi-layer thermal barrier coating.

Description

Technical Field

[0001] This invention relates to multiple technical fields such as coating composite materials, engines, and analysis and testing, and specifically to a test system and method for simulating oil mist erosion of multilayer thermal barrier coatings using electronically controlled fuel injection. Background Technology

[0002] Thermal barrier coatings are widely used on the surfaces of critical components in high-temperature power equipment such as diesel engines, gas turbines, and aero engines to reduce the thermal load on the substrate and extend the service life of the components. To adapt to complex service environments, thermal barrier coatings typically employ a multi-layer structure, including an anti-corrosion layer, a heat insulation layer, an anti-oxidation and corrosion layer, a thermal stress control layer, and a metal bonding layer, as detailed in CN120443095A, CN118422101A, CN118186331A, and CN101660115A.

[0003] During the actual operation of a diesel engine, the high-pressure oil mist formed by the periodic injection of the injector, in addition to participating in combustion, will also have a long-term erosive effect on the inner wall of the combustion chamber and its surface coating, which may cause problems such as surface erosion, microcrack initiation and propagation, and degradation of interlayer bonding performance, thus reducing the service performance and service life of the multilayer thermal barrier coating.

[0004] Existing coating performance evaluation methods mostly focus on thermal cycling tests, particle erosion tests, or high-temperature oxidation tests. These methods struggle to simulate fuel mist erosion conditions under non-real diesel engine conditions, and the erosion conditions are difficult to control precisely, resulting in insufficient test repeatability and comparability. Therefore, it is necessary to develop a new testing system and method that can achieve controllable simulation of fuel mist erosion conditions without the need for real diesel engine conditions, and can also systematically evaluate the fuel mist erosion resistance of multilayer thermal barrier coatings. Summary of the Invention

[0005] The main objective of this invention is to address numerous problems in existing technologies, such as the difficulty in simulating fuel injection mist erosion conditions under non-real diesel engine conditions, the difficulty in precisely controlling erosion conditions, and insufficient test repeatability. A novel electronically controlled fuel injection simulation system and corresponding testing method for multilayer thermal barrier coating fuel mist erosion have been developed. This system not only simulates the erosion conditions of fuel injection mist, reducing testing costs and improving test safety, but also stabilizes the injection conditions through a closed-loop control loop for injection pressure, thereby improving test repeatability and comparability. Furthermore, this method, through a damage closed-loop control loop, achieves controllable adjustment of the erosion damage evolution rate, making it particularly suitable for the systematic evaluation of the overall and layered damage characteristics of multilayer thermal barrier coatings, and has promising application prospects.

[0006] Therefore, the electronically controlled fuel injection simulation multilayer thermal barrier coating oil mist erosion test system provided by the present invention mainly includes: The electronically controlled fuel injection simulation device 2 is mainly used to inject fuel into the multilayer thermal barrier coating sample 5 in a controlled manner and form the fuel mist required for the test. The erosion cavity 3 is mainly used to fix the multilayer thermal barrier coating sample 5 and provide the testing site or space. Damage monitoring device 4 is mainly used to monitor the damage of multilayer thermal barrier coating sample 5 during the test process. The controller 6 is mainly used to control the devices including the electronic fuel injection simulation device 2 and the damage monitoring device 4 to complete the test.

[0007] In the above scheme, the system also includes a fuel supply unit 1, which comprises a fuel tank and a fuel pump. The fuel tank is connected to the electronically controlled fuel injection simulation device 2 via the fuel pump, providing it with the fuel required for testing. The fuel pump is connected to a controller 6 and is controlled by the controller to pump fuel.

[0008] In the above scheme, the system also includes a pressure sensor 7, which is connected to and controlled by the controller 6. The pressure sensor 7 is installed on the fuel supply line between the fuel supply unit 1 and the electronic fuel injection simulation device 2, and / or on the high-pressure fuel line of the electronic fuel injection simulation device 2. The main function of the pressure sensor 7 is to collect the injection pressure signal from the electronic fuel injection simulation device 2 and feed this signal back to the controller 6, which then adjusts the system's injection pressure to maintain stability.

[0009] In the above scheme, the system also includes a height adjustment mechanism, such as a slide rail height adjustment mechanism 9, which is matched with the electronic fuel injection simulation device 2. The electronic fuel injection simulation device 2 is fixed on the height adjustment mechanism and moves linearly with it to adjust various injection parameters, including injection direction, injection height, and injection angle.

[0010] In the above scheme, the system also includes a sample clamping assembly that matches the erosion cavity 3. The sample clamping assembly is provided with at least one sample mounting and fixing position, and the multilayer thermal barrier coating sample 5 is fixed in the sample mounting and fixing position, and then the whole assembly is fixed inside the erosion cavity 3.

[0011] In the above scheme, the damage monitoring device 4 includes an acoustic emission (AE) sensor 8, a preamplifier and filter module, and a data acquisition module. The acoustic emission (AE) sensor 8 is connected to the preamplifier and filter module, which is connected to the data acquisition module. All three components—the acoustic emission (AE) sensor 8, the preamplifier and filter module, and the data acquisition module—are connected to and controlled by the controller 6 or a host computer.

[0012] In the above scheme, the acoustic emission AE sensor 8 is coupled and fixed to the outer wall of the sample clamping assembly or the erosion cavity 3.

[0013] In the above scheme, the multilayer thermal barrier coating sample 5 has a multilayer composite structure, which includes, in sequence, an alloy substrate layer, a metal bonding layer, a thermal stress control layer, an anti-corrosion oxidation layer, a heat insulation layer, and an anti-corrosion layer.

[0014] In the above scheme, the alloy matrix layer is made of nickel-based or cobalt-based high-temperature alloys or nickel-based or cobalt-based heat-resistant stainless steel. The metal bonding layer is made of MCrAlY (where M is Ni and / or Co) alloy or NiAl alloy. The thermal stress control layer is made of metal / ceramic composite material or functionally graded material. The corrosion-resistant oxide layer is made of dense oxide ceramic or its composite material. The thermal insulation layer is made of zirconia-based ceramic (such as 8YSZ) or its composite / doped material. The corrosion-resistant layer is made of dense ceramic material or ceramic-metal composite material.

[0015] The second objective of this invention is to provide a method for using the above-mentioned electronically controlled fuel injection simulation multilayer thermal barrier coating oil mist erosion test system, comprising: fixing at least one multilayer thermal barrier coating sample 5 inside the erosion chamber 3, starting the electronically controlled fuel injection simulation device 2 to perform fuel injection test, using a damage monitoring device 4 to monitor the damage of the sample, using a pressure sensor 7 to monitor the fuel injection pressure, and a controller 6 to adjust the entire test system based on the above monitoring results.

[0016] In the above scheme, before starting the electronic fuel injection simulation device 2 for testing, it is necessary to set / adjust the injection parameters such as injection height H, injection distance, and injection angle in advance.

[0017] In the above scheme, the electronically controlled fuel injection simulation device 2 injects fuel intermittently, and analyzes and tests the multilayer thermal barrier coating sample 5 during the injection interval. The coating's resistance to oil mist erosion is tested by repeating the injection multiple times.

[0018] In the above scheme, the controller 6 controls the entire test process based on at least two loops: an injection pressure closed-loop control loop with the injection pressure signal collected by the pressure sensor 7 as the feedback quantity and a damage closed-loop control loop with the damage characteristic signal collected by the damage monitoring device 4 as the feedback quantity.

[0019] In the above scheme, the regulation process based on the injection pressure closed-loop control loop includes: using pressure sensor 7 to collect the injection pressure signal and feed it back to controller 6, controller 6 regulating the injection parameters of electronic injection simulation device 2 to ensure that the injection pressure remains stable.

[0020] In the above scheme, the control process based on the damage closed-loop control loop includes: using the damage detection device 4 to collect the mass change, surface morphology change, erosion area change, and acoustic emission characteristic quantity change of the multilayer thermal barrier coating sample 5 and form a damage characteristic signal; the controller 6 receives the signal and adjusts the spraying parameters accordingly to ensure the repeatability of the test.

[0021] Compared with existing similar products or technologies, the advantages of this invention are mainly reflected in the following aspects: (1) The entire testing system has a relatively simple structure, is easy to use, and produces accurate and reliable test results with good repeatability. It has good application prospects in the coating performance testing of various engines.

[0022] (2) The present invention uses an electronically controlled fuel injection simulation device to replace the real diesel engine fuel injection environment. It can simulate the oil mist erosion conditions without relying on the whole machine or complex power system, which significantly reduces the test cost, shortens the test cycle, and greatly improves the operability of coating erosion evaluation under laboratory conditions.

[0023] (3) The present invention constructs a closed-loop control loop for injection pressure by using a pressure sensor and a controller, which can correct the injection pressure deviation in real time, so that the actual injection pressure can stably track the target pressure, thereby ensuring the stability of the oil mist erosion intensity, reducing the test error caused by pressure fluctuations, and improving the consistency and repeatability of the test results.

[0024] (4) This invention is mainly used for testing the resistance to oil mist erosion of complex structure coating systems such as multilayer thermal barrier coatings. It can comprehensively evaluate the damage response of different functional layers under stable working conditions, and provides reliable experimental basis for the structural design, process improvement and engineering application of coatings. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the electronically controlled oil spray simulation multilayer thermal barrier coating oil mist erosion test system described in this invention.

[0026] Figure 2 This is a schematic diagram of the structure of the multilayer thermal barrier coating described in this invention.

[0027] Reference numerals: 1-Fuel supply unit, 2-Electronic fuel injection simulation device, 3-Erosion cavity, 4-Damage monitoring device, 5-Multi-layer thermal barrier coating sample, 6-Controller, 7-Pressure sensor, 8-Acoustic emission (AE) sensor, 9-Slide rail height adjustment mechanism. Detailed Implementation

[0028] To enable those skilled in the art to fully understand the purpose, technical solution, and beneficial effects of this invention, the following detailed description of the invention is provided in conjunction with specific embodiments and accompanying drawings. It should be emphasized that the illustrative embodiments and descriptions listed herein are for illustrative purposes only and do not constitute any limitation on the invention.

[0029] It should also be noted that, to avoid obscuring the invention with unnecessary details, the accompanying drawings only show structures and / or method steps closely related to the technical solution of the invention, while other details of the invention are omitted. This does not affect those skilled in the art's understanding and implementation of the invention. The term "comprising / including" in this invention indicates the presence of a feature, element, step, or component, but does not exclude the presence or addition of one or more other features, elements, steps, or components. Unless otherwise specified, the terms "connected" or "linked" can indicate not only a direct connection but also an indirect connection or wireless connection with an intermediary.

[0030] Unless otherwise stated, the descriptions of orientation or positional relationships in this invention, such as "upper," "lower," "left," "right," "front," and "rear," are based on the orientation or positional relationships shown in the accompanying drawings and are used only for the purpose of facilitating the description of this invention and simplifying the description. They are not intended to indicate or imply that the system or element referred to must have a specific orientation or be constructed or operated in a specific orientation, and should not be construed as limiting the technical solution of this invention.

[0031] This invention primarily addresses a series of problems with existing testing methods, such as their inability to simulate fuel mist erosion conditions under non-real diesel engine conditions, or the difficulty in precisely controlling erosion conditions and insufficient repeatability even when simulations are possible. To resolve these issues, a specialized testing system has been developed for methods such as… Figure 2 The multilayer thermal barrier coating sample 5 shown is tested using an electronically controlled fuel injection system to simulate the oil mist erosion of the multilayer thermal barrier coating. This system mainly includes a fuel supply unit 1, an electronically controlled fuel injection simulation device 2, an erosion chamber 3, a damage monitoring device 4, a controller 6, a pressure sensor 7, an acoustic emission (AE) sensor 8, and a slide rail height adjustment mechanism 9. The specific structure or connection relationship of each device is as follows: The fuel supply unit 1 includes a fuel tank and a fuel pump. The fuel pump is connected to the fuel tank and is used to deliver fuel from the fuel tank to the electronic fuel injection simulation device 2.

[0032] The main body of the electronic fuel injection simulation device 2 is an electronic fuel injector. One end of the injector is connected to the fuel supply unit 1 via a fuel pipeline, and the other end faces the multi-layer thermal barrier coating sample 5, which is fixedly installed on the erosion chamber 3. By adjusting the electronic fuel injector, parameters such as the fuel injection direction, injection height, and injection angle can be easily and quickly controlled for better testing.

[0033] The erosion chamber 3 is a closed or semi-closed metal cavity, inside which a matching sample clamping assembly is provided for fixing the multilayer thermal barrier coating sample 5 to be tested. Multiple sample mounting positions (e.g., three at the top, middle, and bottom) are arranged side by side on the sample clamping assembly. The sample mounting positions are all arranged perpendicular to the fuel injection direction to ensure that the sprayed surface of the sample is located in the same injection area.

[0034] The damage monitoring device 4 includes an acoustic emission (AE) sensor 8, a preamplifier and filter module, and a data acquisition module. The AE sensor 8 is electrically connected to the preamplifier and filter module via a signal line, and the preamplifier and filter module is electrically connected to the data acquisition module via a signal line. The AE sensor 8 converts the acoustic emission elastic waves generated by the multilayer thermal barrier coating sample 5 during oil mist erosion into an electrical signal output. The preamplifier and filter module amplifies and bandpass-filters / denoises the weak signal output by the AE sensor 8, improving the signal-to-noise ratio while suppressing non-target signals such as environmental vibrations and electromagnetic interference.

[0035] The preamplifier and filter module can be integrated into a single preamplifier, or it can be composed of a preamplifier and a filter as separate components. The amplified and filtered AE signal is output to the data acquisition module for sampling and digitizing the processed AE signal, and then transmitted to the controller 6 or a host computer (e.g., an industrial control computer) for feature extraction and damage assessment. Based on the acquired AE signal, the controller 6 or host computer calculates damage characteristics such as firing count, amplitude, energy, duration, rise time, and spectral characteristics, and forms a damage index within a preset time window. This damage index is used as feedback in the damage closed-loop control loop to adjust injection parameters such as injection height H.

[0036] In some embodiments, to ensure signal stability, the acoustic emission (AE) sensor 8 is coupled and fixed to the sample clamping assembly or the outer wall of the erosion chamber 3 using a coupling agent. The data acquisition module communicates with the controller 6 or the host computer via wired or wireless means, and the trigger threshold, sampling method, and data caching strategy of the data acquisition module can be set according to the test conditions.

[0037] The cross-sectional structure of multilayer thermal barrier coating sample 5 is as follows: Figure 2As shown, from bottom to top, the coating consists of an alloy substrate, a metal bonding layer, a thermal stress control layer, an anti-corrosion oxide layer, a thermal insulation layer, and an anti-corrosion layer. The alloy substrate can be made of nickel-based, cobalt-based high-temperature alloys, or heat-resistant stainless steel, providing overall load-bearing capacity and structural strength, and serving as the substrate support layer for the coating system. The metal bonding layer can be made of MCrAlY (where M is Ni and / or Co) alloys or NiAl, formed on the surface of the alloy substrate through thermal spraying or other methods. The metal bonding layer mainly improves the bonding strength between the coating and the substrate and forms a stable and dense oxide film at high temperatures, thereby enhancing the coating's oxidation resistance and interfacial stability. The thermal stress control layer can be a metal / ceramic composite transition layer or a functionally graded layer, such as a gradient structure that gradually transitions from the metal bonding layer to the ceramic thermal insulation layer. The thermal stress control layer mainly reduces thermal stress concentration caused by thermal expansion coefficient mismatch, inhibits crack initiation and interlayer delamination, and improves the coating's adaptability to thermal cycling and erosion conditions. The anti-corrosion oxide layer can be made of dense oxide ceramics (such as Al2O3, Cr2O3, TiO2, rare earth modified oxides, etc.) or ceramic composite layers with anti-oxidation / anti-corrosion properties. The anti-corrosion oxide layer mainly serves to block the diffusion of oxygen, sulfur, and fuel-related corrosive media inwards, slowing down high-temperature oxidation and corrosion reactions, thereby protecting the inner structure. The thermal insulation layer is the main thermal barrier functional layer and can be made of stable or partially stable zirconia-based ceramics (such as 8YSZ) and their composite / doped systems. Thermal conductivity is reduced by controlling porosity and microstructure. The thermal insulation layer mainly serves to reduce the thermal load on the substrate and improve thermal gradient conditions. The anti-corrosion layer can be made of dense ceramic layers or ceramic-metal composite layers resistant to oil mist corrosion and erosion, such as corrosion-resistant materials containing Al2O3, Cr2O3, SiO2, etc., or surface layers that have undergone sealing / densification treatment. The anti-corrosion layer mainly serves to resist oil mist erosion, corrosive media intrusion, and surface abrasion, improving the surface durability of the coating.

[0038] Controller 6 is the core control unit of the entire testing system. It is electrically connected to the electronic fuel injection simulation device 2, the damage monitoring device 4, the pressure sensor 7, the acoustic emission (AE) sensor 8, and the slide rail height adjustment mechanism 9, etc., and is used to receive and regulate the signals collected by these devices or sensors. Controller 6 constructs a closed-loop control loop for fuel injection pressure with feedback from the fuel injection pressure signal collected by the pressure sensor 7, and a closed-loop control loop for damage with feedback from the damage characteristic signal collected by the damage monitoring device 4. Through these two loops, the fuel injection parameters, injection height H, etc., are adjusted to obtain a controllable and repeatable fuel mist erosion condition. In this process, the fuel injection parameters include at least fuel injection pressure, injection frequency, injection pulse width, injection duration, injection interval, injection waveform, and fuel injection quantity. Controller 6 can regulate any one or more of these parameters individually or simultaneously. Controller 6 can drive and control the electronic fuel injection simulation device 2 based on the fuel injection pressure deviation using PID control, feedforward and PID combined control, or adaptive control.

[0039] Pressure sensor 7 is installed on the fuel supply line between fuel supply unit 1 and electronic fuel injection simulation device 2, or on the high-pressure fuel line of electronic fuel injection simulation device 2. Pressure sensor 7 is mainly used to collect fuel injection pressure signals and feed them back to controller 6, thereby adjusting the fuel injection parameters of electronic fuel injection simulation device 2. Pressure sensor 7 can be a pressure transmitter or a high-frequency dynamic pressure sensor, capable of outputting analog or digital pressure signals.

[0040] As part of the damage monitoring device 4, the acoustic emission (AE) sensor 8 is fixed to the outer wall of the erosion chamber 3, the sample clamping assembly, or the mounting base of the multilayer thermal barrier coating sample 5. The acoustic emission (AE) sensor 8 is mainly used to collect acoustic emission signals generated during oil mist erosion.

[0041] The slide rail height adjustment mechanism 9 is fixedly connected to the electronically controlled oil injection simulation device 2 and drives it to move up and down, thereby adjusting the spraying parameters such as the spraying height H, spraying distance, and spraying angle of the spraying end of the electronically controlled oil injection simulation device 2 relative to the multilayer thermal barrier coating sample 5. In some embodiments, the slide rail height adjustment mechanism 9 includes a linear guide rail, a slider, an oil injection device mounting base, and a drive assembly. The linear guide rail is fixedly mounted on a mounting plate on the outside of the erosion cavity 3. The slider is connected to the linear guide rail and can reciprocate linearly along the linear guide rail. The oil injection device mounting base is fixedly connected to the slider and slides with it. The electronically controlled oil injection simulation device 2 is fixedly mounted on the oil injection device mounting base, thereby realizing the synchronous movement of the electronically controlled oil injection simulation device 2 and the slider.

[0042] The specific process of using the above system to conduct simulated oil mist erosion tests on multi-layer thermal barrier coatings via electronic fuel injection is as follows: S1: Using the sample clamping assembly, one or more multilayer thermal barrier coating samples 5 are fixedly installed inside the erosion cavity 3. At the same time, the acoustic emission (AE) sensor 8 is installed and fixed to the outer wall of the erosion cavity 3, the sample clamping assembly, or the mounting base of the multilayer thermal barrier coating sample 5.

[0043] In some embodiments, at least three multilayer thermal barrier coating samples 5 are installed side by side on the same inner surface of the erosion cavity 3 from top to bottom or from left to right, so as to conduct oil mist erosion tests simultaneously under the same oil spraying parameters and the same spraying height H.

[0044] S2: The controller 6 controls the slide rail height adjustment mechanism 9 to adjust the parameters such as the injection height H and injection distance of the electronic fuel injection simulation device 2.

[0045] S3: After setting the injection parameters of the electronically controlled fuel injection simulation device 2 through the controller 6, fuel is injected. The injected fuel is fully atomized to form oil mist and acts on the surface of the multilayer thermal barrier coating sample 5.

[0046] It should be noted that the electronic fuel injection simulation device 2 does not continuously inject fuel, but intermittently injects fuel at preset time intervals Δt, with Δt ranging from 0.5 to 12 hours. During the intermittent periods, the mass changes, surface morphology changes, erosion area changes, and acoustic emission characteristic changes of the multilayer thermal barrier coating sample 5 need to be observed, detected, and recorded using damage detection devices 4 and the like.

[0047] S4: Based on the pressure signal collected by the pressure sensor 7, the controller 6 performs closed-loop control of the injection pressure to ensure that the actual injection pressure stably tracks the target pressure. The controller 6 periodically collects the pressure signal and performs filtering processing. When the actual injection pressure is lower than the target pressure, the controller 6 increases the drive output of the electronic injection simulation device 2 (e.g., increases the drive current / voltage or increases the control quantity) to raise the injection pressure; when the actual injection pressure is higher than the target pressure, the controller 6 decreases the drive output of the electronic injection simulation device 2 to lower the injection pressure; when the actual injection pressure enters the preset allowable fluctuation range, the controller 6 maintains or slightly corrects the drive output to maintain pressure stability.

[0048] To achieve the aforementioned closed-loop pressure regulation, controller 6 is selected from any one of PID control, feedforward + PID control, or adaptive control.

[0049] S5: During the oil mist erosion process, damage characteristic signals of each multilayer thermal barrier coating sample 5 are collected by the damage detection device 4, etc. These signals are transmitted to the controller 6, which adjusts the injection parameters, injection height H, etc. based on the damage closed-loop control loop to obtain controllable and repeatable oil mist erosion conditions. As mentioned above, the damage characteristic signals include the firing count, amplitude, energy, duration, rise time, and spectral characteristics of the acoustic emission AE sensor 8.

[0050] The control process based on the damage closed-loop control loop includes: Controller 6 performs statistical analysis and feature extraction on the acoustic emission signal within a preset time window, then combines one or more damage feature quantities to form a damage index, which is used as the outer loop feedback quantity. This damage index is compared with a preset target damage level or target damage rate, and the erosion intensity is adjusted according to the comparison result. When the damage index is lower than the target value (or the growth rate is lower than the target value), the erosion intensity is increased by controller 6. Adjustment methods include increasing the target injection pressure (stable tracking by the pressure inner loop), increasing the injection frequency, increasing the injection pulse width, extending the injection duration, decreasing the injection interval time, decreasing the injection height H, or decreasing the injection distance. When the damage index is higher than the target value (or the growth rate is higher than the target value), the erosion intensity is reduced by controller 6. Adjustment methods include decreasing the target injection pressure, decreasing the injection frequency, decreasing the injection pulse width, shortening the injection duration, increasing the injection interval time, increasing the injection height H, or increasing the injection distance. When the damage index is within the allowable range of the target value (or the growth rate is higher than the target value), controller 6 maintains the current injection parameters and injection height H, continues testing, and records the damage evolution process.

[0051] To avoid frequent adjustments due to transient noise, controller 6 is only triggered to adjust when the damage index deviates continuously from the target value or its trend meets preset conditions within multiple consecutive time windows. After each adjustment, the injection pressure is restored and stabilized first by the inner pressure loop before proceeding to the next round of outer loop judgment, thereby achieving dual closed-loop control with coordinated inner and outer loops.

[0052] S6: Pause fuel injection within a preset time interval Δt, and test, record, and replace each multilayer thermal barrier coating sample 5.

[0053] Repeat steps S3-S5 until the preset termination condition is met, thereby completing the evaluation of oil mist erosion resistance.

Claims

1. A test system for simulating oil mist erosion of multilayer thermal barrier coatings using electronically controlled oil injection, characterized in that... The system includes: An electronically controlled fuel injection simulation device is used to inject fuel into the test sample in a controlled manner and form the fuel mist required for the test. The erosion chamber is used to fix the test sample and provide a testing environment. Damage monitoring device, used to monitor the damage to the test sample during the testing process; The controller is used to regulate the test system.

2. The electronically controlled oil spraying simulation multilayer thermal barrier coating oil mist erosion test system as described in claim 1, characterized in that: The system also includes a fuel supply unit, which includes a fuel tank and a fuel pump. The fuel tank is connected to an electronic fuel injection simulation device via the fuel pump, and the fuel pump is connected to and controlled by a controller.

3. The electronically controlled oil spraying simulation multilayer thermal barrier coating oil mist erosion test system as described in claim 2, characterized in that: The system also includes a pressure sensor connected to and controlled by the controller, which is located on the fuel supply line between the fuel supply unit and the electronic fuel injection simulation device, or on the high-pressure fuel line of the electronic fuel injection simulation device.

4. The electronically controlled oil spraying simulation multilayer thermal barrier coating oil mist erosion test system as described in claim 1, characterized in that: The system also includes a height adjustment mechanism, on which the electronically controlled fuel injection simulation device is fixed and moves.

5. The electronically controlled oil spraying simulation multilayer thermal barrier coating oil mist erosion test system as described in claim 1, characterized in that: The system also includes a sample clamping assembly fixed in the erosion cavity, and at least one sample mounting and fixing position is provided on the sample clamping assembly.

6. The electronically controlled oil spraying simulation multilayer thermal barrier coating oil mist erosion test system as described in claim 1, characterized in that: The damage monitoring device includes an acoustic emission (AE) sensor, a preamplifier and filter module, and a data acquisition module. The acoustic emission (AE) sensor is connected to the preamplifier and filter module, and the preamplifier and filter module is connected to the data acquisition module. The acoustic emission (AE) sensor, the preamplifier and filter module, and the data acquisition module are all connected to and controlled by a controller.

7. The electronically controlled oil spraying simulation multilayer thermal barrier coating oil mist erosion test system as described in claim 1, characterized in that: The test sample has a multi-layer composite structure, which includes, in sequence, an alloy matrix layer, a metal bonding layer, a thermal stress control layer, an anti-corrosion oxidation layer, a heat insulation layer, and an anti-corrosion layer.

8. A method for testing oil mist erosion of multilayer thermal barrier coatings using electronically controlled fuel injection, characterized in that... The method includes: fixing at least one test sample inside the erosion cavity, starting the electronic fuel injection simulation device to perform fuel injection test, using a damage monitoring device to monitor the damage of the sample, using a pressure sensor to monitor the fuel injection pressure, and using a controller to regulate the entire test system based on the monitoring results.

9. The test method as described in claim 8, characterized in that: An electronic fuel injection simulation device intermittently injects fuel, and analyzes and tests the test sample during the injection intervals.

10. The test method as described in claim 8, characterized in that: The controller regulates the entire testing system based on at least two loops, including an injection pressure closed-loop control loop and a damage closed-loop control loop. The regulation process based on the injection pressure closed-loop control loop includes: using a pressure sensor to collect the injection pressure signal and feeding it back to the controller; the controller then regulates the electronic injection simulation device to maintain a stable injection pressure. The regulation process based on the damage closed-loop control loop includes: using a damage detection device to collect changes in the mass, surface morphology, erosion area, and acoustic emission characteristics of the test sample and forming damage characteristic signals; the controller receives these signals and regulates the injection parameters.

Images