Thermal fatigue testing apparatus and method suitable for use with internal flow channel components

Abstract

This invention provides a thermal fatigue testing device and method suitable for components with internal flow channels, including an induction heating device, a water cooling device, a support device, a control device, and a detection device. The water cooling device has its inlet and outlet connected to both ends of the workpiece, forming a coolant circuit. The support device clamps both ends of the workpiece and adjusts its height. The induction heating device includes an induction coil, which is spirally arranged and sleeved on the outside of the workpiece, with a gap between it and the workpiece's outer surface. The control device includes a temperature sensor disposed on the workpiece surface, electrically connected to the water cooling device and the induction heating device. The detection device's probe faces the workpiece surface and is offset from the induction coil. This application has the effect of reproducing the actual operating conditions of a rocket engine in thermal fatigue testing, accurately simulating the cooling conditions of the internal flow channels of a rocket engine, matching the actual heating or cooling rate, and helping to study the thermal fatigue failure mechanism.

Description

Technical Field

[0001] This invention belongs to the field of materials and fatigue testing technology, specifically, it relates to a thermal fatigue testing device and method suitable for components with internal flow channels. Background Technology

[0002] As a key component of rocket engines, regenerative cooling nozzles have advantages such as high energy utilization and reusability. However, during engine startup, the temperature of the wall surface rises sharply due to the high-temperature gas heating, and during shutdown, the temperature of the wall surface drops rapidly due to the low-temperature fuel cooling. Under the action of cyclic thermal load, they are prone to thermal fatigue cracks and failure, which has become a key bottleneck restricting their widespread application. Therefore, studying the thermal fatigue failure mechanism is of great significance for the development of high-performance regenerative cooling nozzles.

[0003] In thermal fatigue testing, the effectiveness of the test hinges on accurately replicating the actual operating conditions of a rocket engine and verifying whether the workpiece structure can simulate the regenerative cooling nozzle structure. Currently, the industry primarily employs induction heating and resistance furnace heating, while cooling methods include surface spray water cooling or air cooling.

[0004] For example, patent document CN120778790A discloses a thermal fatigue testing device for die-casting mold materials, which relates to the field of material performance testing. The device includes a shell, support frame, fixture, first temperature measuring component, mold temperature controller, molten metal heating device, molten metal conveying mechanism, molten metal spraying mechanism, mold release agent spraying mechanism, mold release agent supply mechanism, and control system. One end of the molten metal spraying mechanism is located inside the shell, and the other end is located outside the shell, and it is connected to the molten metal heating device through the molten metal conveying mechanism. One end of the mold release agent spraying mechanism is located inside the shell, and the other end is located outside the shell, and it is connected to the mold release agent supply mechanism. The first temperature measuring component is used to be installed in the test piece. The outlet of the mold temperature controller is used to connect to the inlet of the flow channel inside the test piece, and the inlet of the mold temperature controller is used to connect to the outlet of the flow channel inside the test piece.

[0005] Patent document CN120778790A uses a spray method, which cannot reliably reflect actual operating conditions. When a rocket engine is operating, the temperature rises rapidly to several hundred degrees Celsius within seconds, and then cools back to room temperature within seconds. Insufficient heating or cooling rates will cause the failure mechanism to be inconsistent with actual operating conditions.

[0006] To more accurately simulate the cooling conditions of the internal flow channels of rocket engines and match the actual heating or cooling rates, this invention designs a thermal fatigue testing device and method suitable for components with internal flow channels, thus solving the aforementioned problems. Summary of the Invention

[0007] To address the shortcomings of existing technologies, the purpose of this invention is to provide a thermal fatigue testing device and method suitable for components containing internal flow channels.

[0008] According to the present invention, a thermal fatigue testing device suitable for components with internal flow channels is provided, comprising: an induction heating device, a water cooling device, a support device, a control device, and a detection device; The inlet and outlet of the water cooling device are respectively connected to both ends of the workpiece, forming a coolant circuit; the support device clamps both ends of the workpiece and adjusts the height of the workpiece; the induction heating device includes an induction coil, which is spirally arranged and sleeved on the outside of the workpiece, with a gap between it and the outer surface of the workpiece; the control device includes a temperature sensor disposed on the surface of the workpiece, which is electrically connected to the water cooling device and the induction heating device; the probe of the detection device faces the surface of the workpiece and is offset from the induction coil.

[0009] Preferably, the induction heating device further includes an induction power supply and a power supply water chiller; the induction power supply is placed on a fixed plane; the two ends of the induction coil are fixed to the casing of the induction power supply, the workpiece is height matched with the induction coil, the induction coil is hollow inside for cooling by circulating coolant; the two electrodes of the induction power supply are electrically connected to the induction coil respectively; the power supply water chiller forms two sets of cooling circuits, one set connected to the inside of the induction coil and the other set passing through the inside of the induction power supply.

[0010] Preferably, the oscillation power of the inductive power supply is 1-7 kW, and the operating frequency is 20-80 Hz.

[0011] Preferably, the water-cooling circuit includes a water chiller, water-cooling pipes, and connectors; the water chiller is provided with a coolant inlet and a coolant outlet; the two connectors are respectively inserted into both ends of the workpiece, the connectors are hollow, one end is round, and the other end is an interface that matches the shape of the workpiece; the water-cooling pipes are respectively connected to the connectors and the matching water chiller inlet or outlet, and the coolant circulates between the workpiece and the water chiller along the water-cooling pipes.

[0012] Preferably, the cooling power of the water-cooled machine is 10 kW.

[0013] Preferably, the support device includes clamping blocks and a support frame; the fixed end of the support frame is placed on a fixed surface, and the movable end of the support frame is vertically connected to the fixed end; the clamping blocks are respectively installed on the movable end of the support frame and are detachably positioned on the support frame, and the clamping blocks respectively clamp the water cooling pipes located at both ends of the workpiece in the horizontal direction.

[0014] Preferably, the card block has a vertically formed water pipe fixing hole matching the size of the water cooling pipe, and an expansion joint is formed from the water pipe fixing hole toward the edge of the card block. Two fixing bolt holes for positioning the card block to the support frame are formed at one end of the card block opposite to the water pipe fixing hole. The card block is prepared by photopolymerization 3D printing and the material is PLA. The card block elastically clamps the water cooling pipe by the water pipe fixing hole.

[0015] Preferably, the control device further includes a controller; a temperature sensor is connected to the surface of the workpiece and wound around an induction coil; the controller is electrically connected to an induction power supply, a water chiller, and a temperature sensor; the temperature sensor is a type K thermocouple and is connected to the workpiece by resistance spot welding; the controller is a Siemens PLC.

[0016] Preferably, the detection device includes a laser confocal camera and a camera adjustment bracket; the camera adjustment bracket is placed on a fixed plane; the laser confocal camera is detachably mounted on the camera adjustment bracket, and the position of the laser confocal camera is adjusted to align with the workpiece test area by the camera adjustment bracket.

[0017] According to the present invention, a method for thermal fatigue testing of components containing internal flow channels is provided, employing a thermal fatigue testing device suitable for components containing internal flow channels, and the steps include: Step S1: Obtain target workpiece data. Based on the requirements of temperature, time, morphology characterization, etc. of the workpiece to be tested, determine the shape of the workpiece, the shape of the induction coil, the size of the induction coil, and the distance between the induction coil and the workpiece. Step S2: Based on the target workpiece data and the induction coil data, set the induction heating power and time, the water chiller temperature and flow rate, and the water cooling time; Step S3: Calibrate the test parameters according to the set parameters. The test parameters are calibrated by measuring the temperature sensor readings to ensure they meet the data requirements of the target workpiece. Step S4: Adjust the angle of the laser confocal camera so that the lens is aimed at the test area of ​​the workpiece, and collect microscopic images of the workpiece in real time to provide data support for observing the microscopic deformation and thermal fatigue failure behavior of the material.

[0018] Compared with the prior art, the present invention has the following beneficial effects: 1. The thermal fatigue device provided in this application is suitable for thermal fatigue testing of components with internal flow channels, which is close to the actual working condition.

[0019] 2. The laser confocal camera imaging method provided in this application can acquire the surface morphology of the workpiece in real time and record the microscopic process from crack initiation to expansion and cracking.

[0020] 3. The thermal fatigue testing method provided in this application has good versatility. It can be used to test components with internal flow channels. The supporting parts can be reused and can also be adapted to mechanical fatigue testing machines for thermomechanical fatigue testing. Attached Figure Description

[0021] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings: Figure 1 This invention relates to a thermal fatigue testing device.

[0022] Figure 2 This is a schematic diagram of the workpiece according to the present invention.

[0023] Figure 3 This is a schematic diagram of the card block of the present invention.

[0024] Figure 4 The surface cracks obtained from the test of this invention.

[0025] Figure 5 The surface cracks obtained from the test of this invention.

[0026] The figure shows: 2. Thermal fatigue workpiece; 3. Induction coil; 4. Clamping block; 5. Water cooling pipeline; 6. Laser confocal camera; 7. Temperature sensor; 8. Support frame; 9. Water pipe fixing hole; 10. Fixing bolt hole. Detailed Implementation

[0027] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make several changes and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention.

[0028] like Figures 1-5 As shown, a thermal fatigue testing device suitable for components with internal flow channels includes: an induction heating device, a water cooling device, a support device, a control device, and a detection device. The water-cooling device has inlet and outlet connected to both ends of the workpiece, forming a coolant circuit; the support device clamps both ends of the workpiece and adjusts its height; the induction heating device includes an induction coil 3, which is spirally arranged and sleeved on the outside of the workpiece, with a gap between it and the workpiece's outer surface; the control device includes a temperature sensor 7 disposed on the workpiece surface, which is electrically connected to the water-cooling device and the induction heating device. The probe of the detection device faces the workpiece surface and is offset from the induction coil 3.

[0029] The working principle of this application is as follows: when the induction coil 3 is energized, the workpiece generates an induced current to achieve rapid heating. The water cooling device is connected to the internal flow channel of the workpiece to form a closed coolant circulation, achieving rapid and uniform cooling from the inside of the workpiece. The control device achieves automatic circulation through feedback from the temperature sensor 7. The detection device monitors and records the workpiece in real time. Through the alternating circulation of external heating and internal flow channel water cooling, the service conditions of alternating hot and cold of the workpiece are simulated to achieve automated thermal fatigue testing. At the same time, the temperature and micro-morphology data of the workpiece are collected simultaneously to provide support for thermal fatigue failure analysis.

[0030] Specifically, the induction heating device primarily heats the workpiece to simulate high-temperature conditions. The device also includes an induction power supply and a power supply water chiller. The induction power supply is placed on a fixed plane. The two ends of the induction coil 3 are fixed to the casing of the induction power supply. The workpiece is highly matched to the induction coil 3. The induction coil 3 is hollow inside for cooling by circulating coolant. The two electrodes of the induction power supply are electrically connected to the induction coil 3. The power supply water chiller forms two cooling circuits: one connected to the inside of the induction coil 3, and the other passing through the inside of the induction power supply. Induction heating mainly utilizes the alternating magnetic field generated by energizing the induction coil 3 to induce a current at the workpiece, thereby raising its temperature. Simultaneously, a temperature sensor placed on the surface of the workpiece detects the temperature to meet the workpiece testing requirements.

[0031] In one embodiment, the oscillation power of the inductive power supply is 1-7 kW, and the operating frequency is 20-80 Hz.

[0032] The water-cooling circuit includes a water chiller, water-cooling pipes 5, and connectors. The water chiller has one coolant inlet and one coolant outlet. Two connectors are inserted into both ends of the workpiece, respectively. The connectors are hollow, with one end being round and the other end being an interface that matches the shape of the workpiece. The water-cooling pipes 5 are connected to the connectors and their corresponding water chiller inlet or outlet. The coolant circulates between the workpiece and the water chiller along the water-cooling pipes 5. The coolant inside the workpiece does not affect the surface heating of the workpiece. Compared with traditional air cooling or surface spray water cooling, internal water cooling has a faster cooling effect and less impact on the outer surface of the workpiece. By adjusting the water temperature, flow rate, and time, the temperature is detected by temperature sensors 7 arranged on the surface of the workpiece to meet the workpiece testing requirements.

[0033] In one embodiment, the water cooling system has a cooling power of 10 kW.

[0034] The support device includes a clamping block 4 and a support frame 8; the fixed end of the support frame 8 is placed on the fixed surface, and the movable end of the support frame 8 is raised and lowered to the fixed end; the clamping blocks 4 are respectively installed on the movable end of the support frame 8 and are detachably positioned on the support frame 8; the clamping blocks 4 respectively clamp the water cooling pipes 5 located at both ends of the workpiece in the horizontal direction; the height of the workpiece is adjusted by raising and lowering the support frame 8 so that the workpiece is located in the middle of the induction coil 3.

[0035] In one embodiment, the card block 4 is vertically opened with a water pipe fixing hole 9 to match the size of the water cooling pipe 5, and an expansion joint is opened from the water pipe fixing hole 9 toward the edge of the card block 4. Two fixing bolt holes 10 for positioning the card block 4 relative to the water pipe fixing hole 9 are opened at one end of the card block 4 for positioning the support frame 8. The card block 4 is prepared by photopolymerization 3D printing and the material is PLA. The card block 4 elastically clamps the water cooling pipe 5 by the water pipe fixing hole 9.

[0036] Specifically, the control device also includes a controller; a temperature sensor 7 is connected to the surface of the workpiece and wound around the induction coil 3; the controller is electrically connected to the induction power supply, the water chiller and the temperature sensor 7; when heating, the induction power supply is started, and when the temperature sensor 7 detects that the workpiece has reached the specified temperature, the heating stops and the water chiller is turned on; when the temperature sensor 7 detects that the workpiece is below the specified temperature, the water chiller is turned off and the heating is turned on, so as to realize the thermal fatigue test of cyclic heating and cooling.

[0037] In one embodiment, the temperature sensor 7 is a type K thermocouple, which is connected to the workpiece by resistance spot welding; the controller is a Siemens PLC.

[0038] The detection device includes a laser confocal camera 6 and a camera adjustment bracket. The camera adjustment bracket is placed on a fixed plane; the laser confocal camera 6 is detachably mounted on the camera adjustment bracket, and the position of the laser confocal camera 6 is adjusted by the camera adjustment bracket to align with the workpiece test area, thereby acquiring microscopic images of the sample in real time.

[0039] In one embodiment, the laser confocal camera 6 is a Keyence laser confocal camera.

[0040] This embodiment also provides a method for thermal fatigue testing of components containing internal flow channels, employing a thermal fatigue testing device suitable for components containing internal flow channels, and the steps include: Step S1: Obtain target workpiece data. Based on the requirements of temperature, time, morphology characterization, etc. of the workpiece to be tested, determine the shape of the workpiece, the shape of the induction coil 3, the size of the induction coil 3, and the distance between the induction coil 3 and the workpiece.

[0041] Step S2: Based on the target workpiece data and the data of induction coil 3, set the induction heating power and time, the temperature and flow rate of the water chiller, and the water cooling time.

[0042] Step S3: Calibrate the test parameters according to the set parameters. The test parameters are calibrated by measuring the temperature sensor 7 to ensure they meet the data requirements of the target workpiece.

[0043] Step S4: Adjust the laser confocal camera angle 6 to ensure the lens is precisely aligned with the workpiece test area, and acquire microscopic images of the workpiece in real time to provide data support for observing the microscopic deformation and thermal fatigue failure behavior of the material.

[0044] In one specific embodiment: Step S1: The working requirements for the workpiece to be tested are: heating to 800℃ in 20 seconds, cooling to room temperature in 10 seconds, and a workpiece wall thickness of 1mm. Design the test piece according to the requirements as follows: Figure 2 As shown. Since the workpiece is flat, with a plane and a curved surface on opposite sides, to ensure uniform heating of the plane and to provide an observation position for the laser confocal camera 6, the induction coil 3 is designed as follows: Figure 2 As shown. The outer diameter of induction coil 3 is 50mm, and its distance from the workpiece plane is 10mm.

[0045] Step S2: The induction heating power is 2kW, the operating frequency is 50Hz, and the induction heating time is 20s. The water chiller temperature is 18℃, the flow rate is 1L / min, and the time is 10s. The workpiece meets the testing requirements after passing the type K thermocouple test.

[0046] Step S3: Calibrate the test parameters according to the set parameters. The test parameters are calibrated by measuring the temperature sensor 7 to ensure they meet the data requirements of the target workpiece.

[0047] Step S4: Adjust the laser confocal camera angle 6 to ensure the lens is precisely aligned with the sample testing area, and acquire real-time microscopic images of the sample, such as... Figure 4 , Figure 5 The image shown is a surface topography diagram and a 3D reconstructed image.

[0048] In summary, the embodiments of the present invention provide a thermal fatigue testing device and method suitable for components with internal flow channels. The present invention enables thermal fatigue testing of workpieces with internal flow channels, with testing conditions identical to those of regenerative cooling nozzles. This solves the problem in the prior art where testing requirements deviate significantly from operating conditions, failing to accurately reflect the thermal fatigue failure mechanism. The acquired real-time surface morphology evolution data can strongly support the thermal fatigue failure analysis of such components.

[0049] In the description of this application, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0050] Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. Unless otherwise specified, the embodiments and features described in this application can be arbitrarily combined with each other.

Claims

1. A thermal fatigue testing device suitable for components containing internal flow channels, characterized in that, include: Induction heating device, water cooling device, support device, control device, and detection device; The inlet and outlet of the water cooling device are connected to both ends of the workpiece, forming a coolant circuit; the support device clamps both ends of the workpiece and adjusts the height of the workpiece; the induction heating device includes an induction coil (3), which is spirally arranged and sleeved on the outside of the workpiece, with a gap between it and the outer surface of the workpiece; the control device includes a temperature sensor (7) disposed on the surface of the workpiece, which is electrically connected to the water cooling device and the induction heating device; the probe of the detection device faces the surface of the workpiece and is offset from the induction coil (3).

2. The thermal fatigue testing device for components containing internal flow channels according to claim 1, characterized in that, The induction heating device also includes an induction power supply and a power water chiller; the induction power supply is placed on a fixed plane; the two ends of the induction coil (3) are fixed on the chassis of the induction power supply, the workpiece is height matched with the induction coil (3), the induction coil (3) is hollow inside, and is used for cooling by circulating coolant; the two electrodes of the induction power supply are electrically connected to the induction coil (3); the power water chiller forms two sets of cooling circuits, one set is connected to the inside of the induction coil (3), and the other set is inserted inside the induction power supply.

3. The thermal fatigue testing device for components containing internal flow channels according to claim 2, characterized in that, The oscillation power of the inductive power supply is 1-7kw, and the operating frequency is 20-80Hz.

4. The thermal fatigue testing device for components containing internal flow channels according to claim 1, characterized in that, The water-cooling circuit includes a water chiller, a water-cooling pipeline (5), and connecting nozzles; the water chiller is provided with a coolant inlet and a coolant outlet; the two connecting nozzles are respectively inserted into both ends of the workpiece, the connecting nozzles are hollow, one end is round, and the other end is an interface that matches the shape of the workpiece; the water-cooling pipeline (5) is respectively connected to the connecting nozzles and the water chiller inlet or outlet that matches them, and the coolant circulates between the workpiece and the water chiller along the water-cooling pipeline (5).

5. The thermal fatigue testing device for components containing internal flow channels according to claim 4, characterized in that, The water-cooled machine has a cooling power of 10kW.

6. The thermal fatigue testing device for components containing internal flow channels according to claim 1, characterized in that, The support device includes a clamping block (4) and a support frame (8); the fixed end of the support frame (8) is placed on the fixed surface, and the movable end of the support frame (8) is connected to the fixed end in a lifting manner; the clamping block (4) is installed on the movable end of the support frame (8) and is detachably positioned on the support frame (8); the clamping block (4) clamps the water cooling pipes (5) located at both ends of the workpiece in the horizontal direction.

7. The thermal fatigue testing device for components containing internal flow channels according to claim 6, characterized in that, The card block (4) is vertically opened with a water pipe fixing hole (9) to match the size of the water cooling pipe (5), and an expansion joint is opened from the water pipe fixing hole (9) toward the edge of the card block (4). Two fixing bolt holes (10) for positioning on the support frame (8) are opened at one end of the card block (4) relative to the water pipe fixing hole (9). The card block (4) is prepared by photopolymerization 3D printing and the material is PLA. The card block (4) elastically clamps the water cooling pipe (5) by the water pipe fixing hole (9).

8. The thermal fatigue testing device for components containing internal flow channels according to claim 1, characterized in that, The control device also includes a controller; a temperature sensor (7) is connected to the surface of the workpiece and wound around the induction coil (3); the controller is electrically connected to the induction power supply, the water chiller and the temperature sensor (7); the temperature sensor (7) is a type K thermocouple and is connected to the workpiece by resistance spot welding; the controller is a Siemens PLC.

9. The thermal fatigue testing device for components containing internal flow channels according to claim 1, characterized in that, The detection device includes a laser confocal camera (6) and a camera adjustment bracket; the camera adjustment bracket is placed on a fixed plane; the laser confocal camera (6) is detachably mounted on the camera adjustment bracket, and the position of the laser confocal camera (6) is adjusted to align with the workpiece test area by the camera adjustment bracket.

10. A method for thermal fatigue testing of components with internal flow channels, using the thermal fatigue testing apparatus for components with internal flow channels as described in any one of claims 1-9, characterized in that the steps include... include: Step S1: Obtain target workpiece data. Based on the requirements of temperature, time, morphology characterization, etc. of the workpiece to be tested, determine the shape of the workpiece, the shape of the induction coil (3), the size of the induction coil (3), and the distance between the induction coil (3) and the workpiece. Step S2: Based on the target workpiece data and the induction coil (3) data, set the induction heating power and time, the temperature and flow rate of the water chiller, and the water cooling time; Step S3: Calibrate the test parameters according to the set parameters. The test parameters are calibrated by the temperature sensor (7) to meet the data requirements of the target workpiece. Step S4: Adjust the angle of the laser confocal camera (6) so that the lens is aimed at the test area of ​​the workpiece and collect microscopic images of the workpiece in real time to provide data support for observing the microscopic deformation and thermal fatigue failure behavior of the material.

Images