Thermal Fatigue Test Device and Its Test Method

Abstract

The present invention discloses a thermal fatigue test device and a test method thereof. The thermal fatigue test device includes a heating component, a cooling component and a temperature detector; a plurality of through holes are provided on the heating component, and a plurality of connection ends are provided on the cooling component; each through hole corresponds to a connection end for a test piece to pass through; a cold air channel is provided in the cooling component, an air inlet of the cold air channel is communicated with a cooling gas supply device, and an air outlet of the cold air channel is communicated with the connection end. In the present invention, multiple CMC material and coating test pieces to be measured are heated simultaneously based on a graphite ring and an induction coil to apply a thermal fatigue temperature load; by designing a heat insulation housing to wrap and insulate the graphite ring, the heating efficiency is improved and the induction coil is prevented from bearing high temperature; by designing a test piece mounting seat with an internal cooling air path, active cooling of the test piece during the cooling process is achieved without moving the test piece, the cooling rate is increased, and the test efficiency is effectively improved.

Description

Technical Field

[0001] The present invention relates to the technical field of aviation material testing, and particularly relates to a thermal fatigue test device and a test method thereof. Background Art

[0002] As a new type of ultra-high temperature structural material, ceramic matrix composite (CMC) has excellent thermal physical properties such as light weight and high temperature resistance, so it has broad application prospects in the hot end structure field of aeroengines. Generally, CMC hot end components for aeroengines are usually coated with a coating on the surface to protect the material body. During service, CMC hot end components and the surface coating will undergo severe thermal fatigue loads and may cause coating spalling and material damage. Therefore, the thermal fatigue performance of CMC materials and the surface coating is an important performance index concerned by engineering researchers. Since the peak temperature of the thermal fatigue performance test environment for CMC materials and coatings usually exceeds 1200 °C, and both are not good conductors, most of the existing thermal fatigue performance test devices and methods (especially electromagnetic induction heating methods) applicable to metal materials are no longer applicable.

[0003] Currently, the heating methods for testing the thermal shock performance of CMC materials and coatings mainly use conventional resistance wire heating and chemical fuel combustion heating for testing. However, the heating rate and temperature upper limit of conventional resistance wire heating equipment are relatively low, and usually cannot meet the requirements of test assessment indicators. The test cost of chemical fuel combustion heating equipment is very high, and it will pollute the test piece, thus affecting subsequent research and analysis. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to overcome the defects that the existing methods for testing the thermal shock performance of CMC materials and coatings either have a low heating rate and temperature upper limit and cannot meet the test assessment index requirements, or have a high cost and will pollute the test piece, and to provide a thermal fatigue test device and a test method thereof.

[0005] The present invention solves the above technical problems through the following technical solutions:

[0006] The present invention provides a thermal fatigue test device, which is used to test the thermal fatigue performance of a test piece with a test coating coated on the surface. The thermal fatigue test device includes a heating component, a cooling component and a temperature detection component, and the heating component is arranged on the cooling component;

[0007] A plurality of through holes are provided on the heating component, and a plurality of connection ends with openings are provided on the cooling component; each through hole corresponds to one connection end for one test piece to pass through, and the temperature detection component abuts against the test piece;

[0008] The cooling assembly is provided with a cold air passage. The air inlet of the cold air passage is communicated with a cooling gas supply device, and the air outlet of the cold air passage is communicated with each of the connection ends.

[0009] The heating assembly is used to heat the test piece, the cooling assembly is used to cool down the test piece with cooling gas, and the temperature detection piece is used to detect the temperature value of the test piece in the heating state or the cooling state for thermal fatigue testing of the test piece.

[0010] With this structural arrangement, it achieves effects such as a fast heating rate, a high peak temperature, a simple device structure, and high reliability during the heating-up process, and can simultaneously test multiple test pieces during cooling; the active cooling of the test pieces being tested during the cooling process improves the cooling rate, thereby effectively improving the test efficiency and reducing the cost of the thermal fatigue test.

[0011] Preferably, the heating assembly includes a heating element, the material of the heating element is graphite, and the heating element is provided with a plurality of through holes. The plurality of through holes extend in the same direction, and the hole walls of the through holes surround the test piece.

[0012] This thermal fatigue test device introduces graphite material as the heating element for heating the test piece, and wraps and heats multiple test pieces simultaneously by setting through holes in the heating element, achieving the purpose of high-temperature heating of multiple test pieces for thermal fatigue testing.

[0013] Preferably, the heating assembly further includes an induction coil, and the induction coil is arranged around the heating element with the extension direction of the through hole as the axis;

[0014] The induction coil is electrically connected to a high-frequency AC power supply, and the induction coil is used to inductively heat the heating element after the high-frequency AC power supply is turned on.

[0015] This thermal fatigue test device drives the heating element to heat by setting an induction coil to utilize electromagnetic induction. Compared with the method of driving the heating element to heat by connecting wires and energizing, etc., the induction coil does not need to be in contact with the heating element, which can avoid the influence of high temperature, and both the reliability and durability are improved to a certain extent.

[0016] Preferably, the heating assembly further includes a housing, the housing covers the entire heating element, and the surface of the housing has an avoidance hole for the test piece to pass through. The hole size of the avoidance hole is greater than or equal to the hole size of the through hole.

[0017] The thermal fatigue test device protects the heating element by arranging a housing to wrap the heating element, avoiding damage to the heating element caused by external impacts and other factors. At the same time, this structural arrangement can further improve the heat insulation effect, preventing the high-temperature heating element from affecting the normal operation of other components including the induction coil, and improving the overall operation reliability of the thermal fatigue test device.

[0018] Preferably, the induction coil is arranged outside the housing and positioned on the surface of the housing; or,

[0019] the induction coil is embedded inside the housing; or,

[0020] the induction coil is arranged inside the housing, and a heat insulation layer is provided between the induction coil and the heating element.

[0021] Preferably, the housing includes an upper housing part and a lower housing part that can be combined relatively. The inner wall surfaces of the upper housing part and the lower housing part jointly enclose an accommodation space for accommodating the heating element.

[0022] With this structural arrangement, the forming difficulty and processing difficulty of the housing wrapping the heating element are reduced. At the same time, separating the relatively combined upper housing part and lower housing part also facilitates the maintenance and replacement of the heating element.

[0023] Preferably, the upper housing part and the lower housing part can be combined along the extension direction of the through hole, and the avoidance holes are respectively opened on the upper housing part and the lower housing part.

[0024] With this structural arrangement, it is convenient to set the avoidance holes on the upper housing part and the lower housing.

[0025] Preferably, the lower housing part is provided with a first groove and an opening, and the first groove surrounds the opening; the heating element is arranged in the first groove, and the upper housing part covers the first groove; and / or,

[0026] a boss is provided on the outer surface of the lower housing part, and the induction coil is arranged on the boss; and / or,

[0027] the induction coil is arranged outside the lower housing part.

[0028] Preferably, several first mounting holes are provided on the inner side wall of the first groove, and several second mounting holes corresponding to the first mounting holes are provided on the inner side wall of the heating element;

[0029] the first mounting holes and the second mounting holes are for the temperature detection element to sequentially pass through the inner side walls of the first groove and the heating element to abut against the test piece; and / or,

[0030] The number of the temperature detectors is less than or equal to the number of the through holes.

[0031] With this structure, the thermocouple measures the temperature of the test piece in the test area. By collecting and feeding back the temperature, the closed-loop control of the power input to the heating element is realized, which can improve the heating and temperature control effects of the thermal fatigue test device and improve the consistency between multiple thermal fatigue tests.

[0032] With this structure, the temperature consistency between different test pieces during a single thermal fatigue test of the thermal fatigue test device can be further improved, ensuring that the test effect is completely controllable.

[0033] Preferably, the shape of the heating element is annular, and the through holes are uniformly arranged around the axis of the heating element.

[0034] With this structure, the temperature consistency of the heating element at each through hole is improved, ensuring the consistency of the thermal fatigue test of the thermal fatigue test device for multiple test pieces.

[0035] Preferably, the cooling assembly includes a cooling body, a plurality of connection ends and fixed ends fixed on the cooling body; an installation groove is provided in the connection end, and the test piece in the installation groove is fixedly installed by a fixing member through the fixed end.

[0036] Preferably, a plurality of second grooves are provided on the lower housing part, and each connection end is correspondingly arranged in one of the second grooves.

[0037] Preferably, a cavity structure is provided in the cooling body, and the cavity structure is respectively communicated with the air inlet of the cold air channel and all the installation grooves.

[0038] Preferably, the cooling assembly further includes a connecting member fixed on the cooling body, and the connecting member is respectively communicated with the cavity structure and the air outlet end of the cooling gas supply device.

[0039] Preferably, during the same test process, a plurality of the through holes correspond to a plurality of the test pieces of the same category; or, a plurality of the through holes correspond to a plurality of the test pieces of more than two categories.

[0040] The present invention also provides a test method for a thermal fatigue test device. The test method is implemented based on the above thermal fatigue test device, and the test method includes:

[0041] During the heating test process, the heating assembly is used to heat the test piece;

[0042] The temperature detector is used to detect the temperature value of the test piece in the heating state to perform a thermal fatigue test on the test piece;

[0043] During the cooling test process, the test piece is cooled by the cooling gas through the cooling component;

[0044] The temperature detection component is used to detect the temperature value of the test piece in the cooling state to conduct a thermal fatigue test on the test piece.

[0045] Preferably, in the heating component including a heating element and an induction coil, the material of the heating element is graphite, the induction coil is arranged around the heating element with the extension direction of the through hole as the axis, and when the induction coil is electrically connected to a high-frequency AC power supply, the step of heating the test piece by using the heating component includes:

[0046] Generate a first control command to turn on the high-frequency AC power supply;

[0047] After connecting the high-frequency AC power supply, use the induction coil to inductively heat the heating element to heat the test piece.

[0048] Preferably, the step of cooling the test piece by the cooling gas through the cooling component includes:

[0049] Generate a second control command to turn on the cooling gas supply device;

[0050] Use the cooling gas supply device to input cooling gas to flow through each test piece to cool the test piece.

[0051] On the basis of conforming to the common knowledge in the art, the above preferred conditions can be combined arbitrarily to obtain various preferred embodiments of the present invention.

[0052] The positive and progressive effects of the present invention are as follows:

[0053] In the present invention, by introducing graphite material as the heating element for heating the test piece and using an induction coil to conduct inductive heating on it, and then heating multiple CMC material and coating test pieces to be measured simultaneously through thermal radiation and heat conduction to apply a thermal fatigue temperature load; by designing a heat insulation housing to wrap and insulate the graphite ring, the heating efficiency is improved and the induction coil is prevented from bearing high temperatures, saving the cooling system of the induction coil; by designing a test piece mounting seat with an internal cooling gas path, active cooling of the test piece during the cooling process is realized without moving the test piece, improving the cooling rate. That is, the thermal fatigue test device has the advantages of fast heating rate, high peak temperature, simple device structure, high reliability, etc., and can test multiple test pieces simultaneously, effectively reducing the energy consumption of the test and thus improving the test efficiency and reducing the cost of the thermal fatigue test. Description of the Drawings

[0054] Figure 1 Schematic structural diagram of the thermal fatigue test device according to Embodiment 1 of the present invention.

[0055] Figure 2 Schematic cross-sectional structural diagram of the thermal fatigue test device according to Embodiment 1 of the present invention.

[0056] Figure 3 Schematic structural diagram of the heating element according to Embodiment 1 of the present invention.

[0057] Figure 4 Schematic structural diagram of the housing according to Embodiment 1 of the present invention.

[0058] Figure 5 First schematic structural diagram of the lower housing part according to Embodiment 1 of the present invention.

[0059] Figure 6 Second schematic structural diagram of the lower housing part according to Embodiment 1 of the present invention.

[0060] Figure 7 Schematic cross-sectional structural diagram of the lower housing part according to Embodiment 1 of the present invention.

[0061] Figure 8 Schematic structural diagram of the cooling assembly according to Embodiment 1 of the present invention.

[0062] Figure 9 First schematic cross-sectional structural diagram of the cooling assembly according to Embodiment 1 of the present invention.

[0063] Figure 10 Second schematic cross-sectional structural diagram of the cooling assembly according to Embodiment 1 of the present invention.

[0064] Figure 11 Flowchart of the test method of the thermal fatigue test device according to Embodiment 2 of the present invention. Detailed implementation manners

[0065] The present invention will be further described below by way of embodiments, but the present invention is not limited to the scope of the described embodiments.

[0066] Embodiment 1

[0067] The thermal fatigue test device of this embodiment is used to test the thermal fatigue performance of a test piece with a tested coating applied on its surface.

[0068] As Figures 1-4 shown, the thermal fatigue test device of this embodiment includes a heating assembly 1, a cooling assembly 2, and a temperature detection element 3 (not shown in the figure), and the heating assembly 1 is arranged on the cooling assembly 2.

[0069] The heating component 1 is provided with a plurality of through holes 4, and the cooling component 2 is provided with a plurality of connection ends with openings; each through hole 4 corresponds to a connection end for a test piece A to pass through, and the temperature detection piece 3 abuts against the test piece A.

[0070] In a feasible embodiment, the through hole 4 is a long hole adapted to the test piece A; of course, the through hole 4 can also be set in other shapes, as long as it can be adapted to the test piece A or can ensure that the test piece A can pass through.

[0071] The cooling component 2 is provided with a cold air channel, the air inlet of the cold air channel is communicated with the cooling gas supply device, and the air outlet of the cold air channel is communicated with each connection end;

[0072] The heating component 1 is used to heat the test piece A, the cooling component 2 is used to cool the test piece A with cooling gas, and the temperature detection piece 3 is used to detect the temperature value of the measured area of the test piece A in the heating state or the cooling state to perform a thermal fatigue test on the test piece A.

[0073] The heating component 1, the cooling gas supply device and the temperature detection piece 3 are all connected to an external control device. During the heating test process, the external control device is used to control the high-frequency AC power supply to turn on to heat the heating component 1, the cooling gas supply device is turned off, and the temperature data of the test piece A detected by the temperature detection piece 3 is obtained in real time. Based on the thermal fatigue temperature-time load spectrum designed in the test as the target, the output power of the high-frequency AC power supply is adjusted through closed-loop control so that the heating rate and the heat preservation duration of the measured area of the test piece A meet the test requirements. After the heating and heat preservation state ends and enters the cooling state, the high-frequency AC power supply is turned off and the cooling gas supply system is turned on; when entering the cooling state after the heating and heat preservation state ends, the high-frequency AC power supply is controlled to be turned off, the cooling gas supply system is turned on for cooling, the temperature data of the test piece A detected by the temperature detection piece 3 is obtained in real time, and based on the thermal fatigue temperature-time load spectrum designed in the test as the control target, the cooling gas flow parameters are adjusted through closed-loop control so that the cooling rate and the heat preservation duration of the measured area of the test piece A meet the test requirements.

[0074] In addition, during the same test process, multiple through holes 4 correspond to multiple test pieces A of the same category; or, multiple through holes 4 correspond to multiple test pieces A of two or more categories.

[0075] By testing multiple test pieces A simultaneously, the test energy consumption can be effectively reduced and the test efficiency can be improved; by testing different test pieces A simultaneously, the test efficiency can be further improved to meet higher test requirements.

[0076] Specifically, as Figure 3 shown, the heating component 1 of this embodiment includes a heating element 11, an induction coil 12 and a housing 13 (not shown in the figure).

[0077] In the solution of an embodiment, the heating element 11 is made of graphite. A plurality of through holes 4 are provided on the heating element 11. The plurality of through holes 4 extend in the same direction, and the hole walls of the through holes 4 surround the test piece A.

[0078] In the solution of an embodiment, the shape of the heating element 11 is annular, that is, the heating element 11 is a graphite ring. The through holes 4 are uniformly arranged around the axis of the graphite ring. A plurality of perforations C are provided on the inner side wall of the graphite ring for the temperature detection element to pass through. All the elements docked with the heating element 11 are arranged in a matching shape. Of course, the through holes 4 can also be arranged according to other setting methods according to actual design requirements.

[0079] The induction coil 12 is arranged around the heating element 11 with the extension direction of the through hole 4 as the axis, and the induction coil 12 is electrically connected to a high-frequency AC power supply. The induction coil 12 is used to inductively heat the heating element 11 after the high-frequency AC power supply is turned on. The high-frequency AC power supply is connected to an external control device and is turned on or off according to the control instructions of the external control device to start or stop heating the heating element 11.

[0080] Based on the graphite material with good electrical conductivity, a graphite ring heating element is designed. The graphite ring is heated by electromagnetic induction using a high-frequency AC power supply and the induction coil 12, which has the characteristics of fast heating rate and high upper limit of the heatable temperature to ensure the feasibility of the thermal fatigue test of the tested CMC test piece A. A plurality of long holes penetrating the thickness direction are uniformly arranged along the circumferential direction of the cross section of the graphite ring for the tested CMC test piece A to pass through, that is, the tested part of the CMC test piece A is wrapped by the graphite ring, ensuring the heating test effect on the test piece A and achieving the purpose of simultaneously testing multiple test pieces A, improving the test efficiency and reducing the test cycle and cost.

[0081] As Figures 4-7 shown, the housing 13 covers the entire heating element 11 to form a wrapped test area. The surface of the housing 13 has an avoidance hole B for the test piece A to pass through, and the hole size of the avoidance hole B is greater than or equal to the hole size of the through hole 4.

[0082] By designing the heat-insulating housing 13 to wrap and insulate the graphite ring, the heating efficiency is improved and the induction coil 12 is prevented from bearing high temperature, eliminating the cooling system of the induction coil 12.

[0083] The induction coil 12 is arranged on the outer side of the housing 13 and positioned on the surface of the housing 13; or, the induction coil 12 is embedded inside the housing 13; or, the induction coil 12 is arranged on the inner side of the housing 13, and a heat-insulating layer is provided between the induction coil 12 and the heating element 11. Preferably, the induction coil 12 is arranged on the outer side of the housing 13 and positioned on the surface of the housing 13.

[0084] The housing 13 includes an upper housing part 14 and a lower housing part 15 that can be relatively combined. The inner wall surfaces of the upper housing part 14 and the lower housing part 15 together define a receiving space for accommodating the heating element 11. The upper housing part 14 and the lower housing part 15 can be combined along the extending direction of the through hole 4, and the avoidance holes B are respectively formed in the upper housing part 14 and the lower housing part 15. Both the housing part 13 and the lower housing part 15 are made of materials such as high-temperature resistant, oxidation-resistant, and poor conductor materials, such as refractory brick materials.

[0085] In an embodiment of the solution, as Figure 5 shown, a first groove 16 and an opening 17 are provided on the lower housing part 15, and the first groove 16 is arranged around the opening 17; the heating element 11 is arranged in the first groove 16, and the upper housing part 14 is covered on the first groove 16 to wrap the graphite ring to achieve the effects of heat insulation and improving heating efficiency.

[0086] A boss 18 is provided on the outer surface of the lower housing part 15, and the induction coil 12 is arranged on the boss 18 to support the induction coil 12; in addition, a plurality of second grooves 19 are provided on the lower housing part 15. The induction coil 12 is arranged outside the lower housing part 15.

[0087] A plurality of first mounting holes are provided on the inner side wall of the first groove 16, and these first mounting holes are arranged in one-to-one correspondence with a plurality of through holes C on the heating element. The first mounting holes are for the temperature detection element 3 to sequentially pass through the inner side wall of the first groove 16 and the heating element to abut against the test piece A, and the temperature detection elements 3 are all arranged in the space corresponding to the opening 17.

[0088] Among them, the number of the temperature detection elements 3 is less than or equal to the number of the through holes 4. The temperature detection elements 3 include but are not limited to thermocouple temperature measurement elements with ceramic packaging. The thermocouple temperature measurement ends abut against the surface of the measured area of the test piece A, and are used to monitor the temperature value of the test area of the test piece A during the test process and feed it back to the external control device in real time.

[0089] Preferably, as Figure 5 and 7 shown, the measurement end of each thermocouple abuts against the center position of the surface of the measured area of the test piece A, so as to reflect the real-time temperature of the corresponding test piece A to the greatest extent, ensure the accuracy of temperature data detection, and further improve the reliability of the test detection results.

[0090] When the heating element 11 is in a ring structure, both the upper housing part 14 and the lower housing part 15 in the housing 13 adapted to be installed therewith are in ring structures, the first groove 16 is an annular groove, and the opening 17 is a circular opening 17.

[0091] In the heating and temperature - rising state, the graphite ring heated by electromagnetic induction heats up rapidly, and then rapidly heats the test piece A material and its coating in the wrapped area through thermal radiation and thermal convection. The graphite ring is placed in the annular groove of the lower housing part 15 of the annular heat - insulating housing 13, and an annular cover (i.e., the upper housing part 14) is covered on the upper part to form a wrapping of the graphite ring, thereby reducing the heat loss of the graphite ring in the heating state. While effectively improving the heating efficiency of the graphite ring for the test piece A, it also avoids the induction coil 12 from being overheated, thus eliminating the cooling system of the induction coil 12.

[0092] As Figure 8 and 10 shown, the cooling assembly 2 of this embodiment includes a cooling main body 21, a plurality of connection ends 22 and fixed ends 23 fixedly arranged on the cooling main body 21; an installation groove is provided in the connection end 22, and the fixed end 23 is fixedly installed on the test piece A in the installation groove through a fixing member.

[0093] The cooling main body 21 is the mounting seat. The test piece A is installed and fixed between each connection end 22 and the fixed end 23 through mounting bolts. Of course, other fixing methods that can fix each test piece A can be designed according to actual needs, so it will not be elaborated here. In addition, the cooling air path in the mounting seat can be blocked by mounting bolts to form the function of a correct cold air flow path, thereby reducing the processing difficulty of the cold air channel of the mounting seat.

[0094] Among them, a plurality of second grooves are provided on the lower housing part 15, and each connection end 22 is correspondingly arranged in one second groove.

[0095] In an embodiment of the solution, the lower housing part 15 is of a ring - shaped structure, and a plurality of circular grooves are evenly arranged along the circumference at its bottom for mating installation with the circular - raised connection ends 22 on the upper surface of the mounting seat, so as to reduce the installation alignment difficulty and improve the sealing performance of the cooling air path. A vertical cold air channel is provided inside the circular - raised connection end 22, which is integrally formed with the corresponding installation groove, and the installation groove is used for the test piece A to be inserted and installed for limiting to facilitate installation and fixation.

[0096] A cavity structure 24 is provided inside the cooling main body 21, and the cavity structure 24 is respectively communicated with the air inlet of the cold air channel and all the installation grooves. The cooling assembly 2 further includes a connecting member 25 fixedly arranged on the cooling main body 21, and the connecting member 25 is respectively communicated with the cavity structure 24 and the air outlet end of the cooling gas supply device.

[0097] In the temperature - decreasing state, the cooling gas supply device supplies cold air to guide the cooling gas to wash the test area of the test piece A, thereby playing a role in cooling and temperature - decreasing.

[0098] In the solution of an embodiment, the cooling body 21 includes a horizontally arranged base structure and a support structure vertically fixed on the base structure, and the connecting member 25 is fixed on the support structure. Among them, both the connecting end 22 and the fixed end 23 are fixed in the base structure, as Figure 8 and 11 shown, horizontally distributed cold air channels D leading from the center to the installation grooves corresponding to each test piece A are machined inside the base structure, a vertical cold air channel E communicating with the horizontal cold air channel is provided inside the support structure, an intake cold air channel F communicating with the vertical cold air channel is provided on the connecting member 25, and the connecting member 25 is connected to a cold air source.

[0099] As Figure 9 shown, during the cooling process, the flow path of the cooling gas in the thermal fatigue test device of this embodiment is (arrow direction): successively through the cold air channels in the connecting member 25, the cold air channels inside the support structure, the cold air channels inside the base structure, and the cold air channels corresponding to each installation groove in the base structure, and then discharged upward.

[0100] In this embodiment, by designing a mounting seat with internal cold air channels, active cooling of the test piece during the cooling process is achieved, and the cooling rate is increased.

[0101] The installation process corresponding to the thermal fatigue test device in this embodiment is as follows:

[0102] Fix the upper and lower ends of the mounting seat, and connect the cold air supply pipeline to the cooling gas supply equipment; place the test piece in the installation groove and complete the tightening and fixing with the installation bolts; then install the lower shell part of the heat insulation shell on the mounting seat, ensure that the test piece passes through the long hole, and insert the connecting end of the circular protrusion on the upper surface of the mounting seat into the circular groove at the bottom of the lower shell part of the heat insulation shell; then place the graphite ring and the upper cover plate in the annular groove of the lower shell part in sequence, and then pass the thermocouple through the first groove in the heat insulation shell and the graphite ring in sequence to abut against each test piece, and connect the thermocouple to the temperature data acquisition device of the external control equipment; sleeved the induction coil around the heat insulation shell and place it on the convex platform on the periphery of the shell for support, and finally electrically connect the induction coil to the high-frequency AC power supply, thus completing the construction of the test device system.

[0103] The working principle corresponding to the thermal fatigue test device in this embodiment is as follows:

[0104] Under the heating and temperature-rising state, the external control device controls the cooling gas supply system to close, and at the same time turns on the high-frequency AC power supply. The induction coil heats the graphite ring through induction heating. Then, the graphite ring heats the test area of the test specimen through thermal radiation and thermal convection. The thermocouple monitors the temperature of the tested area of the specimen in real time and feeds it back to the external control device. The external control device targets the thermal fatigue temperature-time load spectrum designed in the experiment, and adjusts the output power of the high-frequency AC power supply through closed-loop control, so that the heating rate and heat preservation duration of the tested area of the test specimen meet the test requirements.

[0105] When entering the cooling state after the heating and heat preservation state ends, the external control device turns off the high-frequency AC power supply and at the same time turns on the cooling gas supply system. The external control device uses the temperature value fed back by the thermocouple in real time as the control input, and the thermal fatigue temperature-time load spectrum designed in the experiment as the control target, and adjusts the cooling gas flow parameters through closed-loop control, so that the cooling rate and heat preservation duration of the tested area of the test specimen meet the test requirements; after the cooling process ends, it repeats to enter the heating and heat preservation process of the next thermal fatigue cycle, and the test process is similar to the foregoing, until the entire thermal fatigue test is completed.

[0106] During the above entire thermal fatigue loading test process, the temperature measurement data of the thermocouple is used as the control input of the external control device, and the high-frequency AC power supply and the cooling gas supply system are controlled by the external control device to be automatically turned on and off alternately.

[0107] In this embodiment, by introducing a graphite material as the heating element for heating the test specimen and using an induction coil to perform induction heating on it, and then heating multiple tested CMC material and coating specimens simultaneously through thermal radiation and heat conduction to apply the thermal fatigue temperature load; by designing a heat-insulating housing to wrap and insulate the graphite ring, the heating efficiency is improved and the induction coil is prevented from bearing high temperatures, saving the cooling system of the induction coil; by designing a test specimen mounting seat with an internal cooling gas path, active cooling of the test specimen during the cooling process is achieved without moving the test specimen, improving the cooling rate. That is, this thermal fatigue test device has the advantages of fast heating rate, high peak temperature, simple device structure, high reliability, etc., and can test multiple specimens simultaneously, effectively reducing the energy consumption of the test, thus improving the test efficiency and reducing the cost of the thermal fatigue test.

[0108] Embodiment 2

[0109] The test method of the thermal fatigue test device in this embodiment is implemented based on the thermal fatigue test device in Embodiment 1.

[0110] As Figure 11 shown, the test method of the thermal fatigue test device in this embodiment includes:

[0111] S101. During the heating test process, use a heating component to heat the test piece;

[0112] Use a temperature detection component to detect the temperature value of the test piece in the heated state to conduct a thermal fatigue test on the test piece;

[0113] Specifically, when the heating component includes a heating element and an induction coil, the material of the heating element is graphite, the induction coil is arranged around the heating element with the extension direction of the through hole as the axis, and when the induction coil is electrically connected to a high-frequency AC power supply, the steps of using the heating component to heat the test piece include:

[0114] Generate a first control command to turn on the high-frequency AC power supply;

[0115] After turning on the high-frequency AC power supply, use the induction coil to inductively heat the heating element to heat the test piece.

[0116] S102. During the cooling test process, use a cooling gas to cool the test piece through a cooling component;

[0117] Use a temperature detection component to detect the temperature value of the test piece in the cooled state to conduct a thermal fatigue test on the test piece.

[0118] Specifically, the steps of using a cooling gas to cool the test piece through a cooling component include:

[0119] Generate a second control command to turn on the cooling gas supply device;

[0120] Use the cooling gas supply device to input the cooling gas to flow through each test piece to cool the test piece.

[0121] In the heating and warming state, the external control device controls the cooling gas supply system to close, and at the same time turns on the high-frequency AC power supply. The induction coil inductively heats the graphite ring, and then the graphite ring heats the test area of the test piece to be tested through thermal radiation and thermal convection. The thermocouple monitors the temperature of the test area of the test piece in real time and feeds it back to the external control device. The external control device aims at the thermal fatigue temperature-time load spectrum designed in the test, and adjusts the output power of the high-frequency AC power supply through closed-loop control so that the heating rate and the heat preservation duration of the test area of the test piece meet the test requirements.

[0122] When entering the cooling state after the heating and heat preservation state ends, the external control device shuts off the high-frequency AC power supply and simultaneously turns on the cooling gas supply system. The external control device uses the temperature value real-time feedback by the thermocouple as the control input, takes the thermal fatigue temperature-time load spectrum designed by the experiment as the control target, and adjusts the cooling gas flow parameters through closed-loop control so that the cooling rate and heat preservation duration of the measured area of the test piece meet the test requirements; after the cooling process ends, it repeats to enter the heating and heat preservation process of the next thermal fatigue cycle, and the testing process is similar to the foregoing until the entire thermal fatigue test is completed.

[0123] During the above entire thermal fatigue loading test process, the temperature measurement data of the thermocouple is used as the control input of the external control device, and the high-frequency AC power supply and the cooling gas supply system are automatically turned on and off alternately under the control of the external control device.

[0124] In this embodiment, it realizes the effects of fast heating rate, high peak temperature, simple device structure, high reliability, etc. during the heating and temperature rising process, and can simultaneously test multiple test pieces during cooling; the active cooling of the test piece being tested during the cooling process improves the cooling rate, thereby effectively improving the test efficiency and reducing the cost of the thermal fatigue test.

[0125] Although the specific implementation manners of the present invention have been described above, those skilled in the art should understand that this is only an example, and the protection scope of the present invention is defined by the appended claims. Without departing from the principles and essence of the present invention, those skilled in the art can make various changes or modifications to these implementation manners, but these changes and modifications all fall within the protection scope of the present invention.

Claims

1. A thermal fatigue test device for testing the thermal fatigue performance of a test piece with a test coating applied on its surface, characterized in that, The thermal fatigue test device includes a heating component, a cooling component, and a temperature detector. The heating component is disposed on the cooling component. The heating component is provided with a plurality of through holes, and the cooling component is provided with a plurality of connection ends having openings. Each through hole corresponds to one connection end for a test piece to pass through, and the temperature detector abuts against the test piece. A cold air channel is provided in the cooling component. An air inlet of the cold air channel is communicated with a cooling gas supply device, and an air outlet of the cold air channel is communicated with each connection end. The heating component is used to heat the test piece, the cooling component is used to cool the test piece with cooling gas, and the temperature detector is used to detect the temperature value of the test piece in the heating state or the cooling state to perform a thermal fatigue test on the test piece. The heating component includes a heating element made of graphite. The heating element is provided with a plurality of through holes, and the plurality of through holes extend in the same direction. The hole wall of the through hole surrounds the test piece. The heating component further includes an induction coil that surrounds the heating element with the extension direction of the through hole as the axis. The induction coil is electrically connected to a high-frequency AC power supply, and the induction coil is used to inductively heat the heating element after the high-frequency AC power supply is turned on. The heating component further includes a housing that covers the entire heating element. The surface of the housing has an avoidance hole for the test piece to pass through, and the hole size of the avoidance hole is greater than or equal to the hole size of the through hole. The induction coil is disposed outside the housing and positioned on the surface of the housing; or, The induction coil is embedded inside the housing; or, The induction coil is disposed inside the housing, and a heat insulation layer is provided between the induction coil and the heating element.

2. The thermal fatigue test device according to claim 1, characterized in that, The housing includes an upper housing part and a lower housing part that can be combined relatively. The inner wall surfaces of the upper housing part and the lower housing part jointly enclose an accommodation space for accommodating the heating element.

3. The thermal fatigue test device according to claim 2, wherein, The upper housing part and the lower housing part can be combined along the extension direction of the through hole, and the avoidance holes are respectively opened on the upper housing part and the lower housing part.

4. The thermal fatigue test device according to claim 3, characterized in that, The lower housing part is provided with a first groove and an opening. The first groove surrounds the opening. The heating element is disposed in the first groove, and the upper housing part covers the first groove; and / or, A boss is provided on the outer surface of the lower housing part, and the induction coil is disposed on the boss; and / or, The induction coil is disposed outside the lower housing part.

5. The thermal fatigue test device according to claim 4, characterized in that, A plurality of first mounting holes are provided on the inner side wall of the first groove, and a plurality of second mounting holes corresponding to the first mounting holes are provided on the inner side wall of the heating element. The first mounting hole and the second mounting hole are for the temperature detector to sequentially pass through the inner side walls of the first groove and the heating element to abut against the test piece; and / or, The number of the temperature detectors is less than or equal to the number of the through holes.

6. The thermal fatigue test device according to any one of claims 1-5, characterized in that, The shape of the heating element is annular, and the through holes are uniformly arranged centered on the axis of the heating element.

7. The thermal fatigue test device according to claim 2, wherein The cooling assembly includes a cooling body, a plurality of connection ends and fixed ends fixedly arranged on the cooling body; an installation groove is arranged in the connection end, and the fixed end is fixedly installed in the test piece in the installation groove through a fixing member.

8. The thermal fatigue test device according to claim 7, wherein A plurality of second grooves are arranged on the lower housing portion, and each connection end is correspondingly arranged in one of the second grooves.

9. The thermal fatigue test device according to claim 7 or 8, characterized in that, A cavity structure is arranged in the cooling body, and the cavity structure is communicated with the air inlet of the cold air channel and all the installation grooves respectively.

10. The thermal fatigue test device according to claim 9, wherein, The cooling assembly further includes a connecting member fixedly arranged on the cooling body, and the connecting member is communicated with the cavity structure and the air outlet end of the cooling gas supply device respectively.

11. The thermal fatigue test device according to claim 1, characterized in that, During the same test process, a plurality of the through holes correspond to a plurality of test pieces of the same category; or, a plurality of the through holes correspond to a plurality of test pieces of two or more categories.

12. A test method for a thermal fatigue test device, characterized in that, The test method is implemented based on the thermal fatigue test device according to any one of claims 1-11, and the test method includes: During the heating test process, the heating assembly is used to heat the test piece; The temperature detection member is used to detect the temperature value of the test piece in the heated state to perform thermal fatigue testing on the test piece; During the cooling test process, the cooling assembly is used to cool the test piece with cooling gas; The temperature detection member is used to detect the temperature value of the test piece in the cooled state to perform thermal fatigue testing on the test piece.

13. The test method of the thermal fatigue test device according to claim 12, characterized in that, When the heating assembly includes a heating element and an induction coil, the material of the heating element is graphite, the induction coil is arranged around the heating element with the extending direction of the through hole as the axis, and when the induction coil is electrically connected to a high-frequency AC power supply, the step of using the heating assembly to heat the test piece includes: Generating a first control instruction to turn on the high-frequency AC power supply; After turning on the high-frequency AC power supply, the induction coil is used to inductively heat the heating element to heat the test piece.

14. The test method of the thermal fatigue test device according to claim 12, characterized in that The step of using the cooling assembly to cool the test piece with cooling gas includes: Generating a second control instruction to turn on the cooling gas supply device; The cooling gas supply device is used to input cooling gas to flow through each test piece to cool the test piece.

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