Transient convective heat transfer test method for ceramic matrix composite component under high-temperature oxidation

Abstract

The invention discloses a transient convective heat transfer test method for a ceramic matrix composite component under high-temperature oxidation, and belongs to the field of engineering thermophysics. According to the transient flow heat exchange characteristic test method established by the invention, transient flow heat exchange characteristic test research in a high-temperature oxidation characteristic environment can be carried out on the CMC material component, thermal response characteristics and change rules of the CMC material component at different oxidation temperatures and time are obtained, and a foundation is laid for application of the CMC material component in aerospace high-temperature components. And a principle test verification method of the analysis model is provided.

Description

Technical Field

[0001] The invention relates to the technical field of engineering thermal physics, and in particular to a transient convection heat transfer test method for a ceramic-based composite material component under high-temperature oxidation. Background Art

[0002] In the face of future design requirements such as higher thermodynamic cycle parameters (gas temperature exceeding 2200K), longer component life and reliability (life exceeding 6000 hours), the development of high-temperature components for the new generation of aircraft engines, especially turbine blades, has brought outstanding challenges. The existing turbine blade design capabilities based on high-temperature alloys have reached their limits. The application of composite materials represented by ceramic matrix composites (Ceramic Catrix Composites, CMC for short) provides the most possible and promising solution.

[0003] CMC used in the hot end parts of aircraft engines, whether C / SiC composites or SiC / SiC composites, are usually manufactured by methods such as CVI, PIP and RMI. During the preparation process, pores will inevitably be generated inside the CMC. In addition, the huge difference in thermal expansion coefficients between the fiber and the matrix will cause microcracks to form in the matrix. These pores and microcracks provide channels for the oxidizing medium to enter the material when the CMC hot end parts are in service. As the service time of the CMC hot end parts accumulates, the fibers and interfaces are gradually oxidized. The thermal properties of the composite material change with the increase in service time, which in turn affects the temperature field distribution characteristics of the CMC hot end parts under the engine service environment, as well as the thermal response characteristics of the CMC hot end parts under the engine transient state. Therefore, it is urgent to obtain the transient convective heat transfer characteristics of the CMC hot end parts in a high-temperature oxidizing environment to provide support for the temperature field characteristics analysis and cooling design of the CMC hot end parts under the characteristics of the high-temperature service environment of aircraft engines. The present invention aims at a typical flat plate component of CMC material and establishes a transient convection heat transfer test method for ceramic matrix composite components under high-temperature oxidation, which provides a principle verification test method and platform for the thermal analysis and cooling design of the hot end components of CMC materials of my country's advanced aero-engines under the characteristics of high-temperature oxidation service environment. Summary of the invention

[0004] The present invention provides a transient convection heat transfer test method for ceramic matrix composite material components under high-temperature oxidation, which can be used to carry out transient flow heat transfer characteristic test research on CMC material components under high-temperature oxidation characteristic environment, and obtain the thermal response characteristics and change laws of CMC material components under different oxidation temperatures and times.

[0005] The embodiment of the present invention provides a method for testing transient convection heat transfer of ceramic matrix composite components under high temperature oxidation, comprising the following steps:

[0006] Step 1: Based on the representative characteristics of the CMC material flat plate component, measure the mass, equivalent thermal conductivity, and thermal diffusion coefficient of the CMC material flat plate component;

[0007] Step 2: Install the test CMC material flat plate component on the transient thermal response test section, which has two high-temperature mainstream outlets regulated by transient heat flow switching plugs. During the experiment, adjust the cold flow in the transient thermal response test section channel to reach the test setting and maintain stability;

[0008] Step 3: Open the second transient heat flow switching plug plate 2 of the transient thermal response test section, close the first transient heat flow switching plug plate 1, open the air supply system to allow the high-temperature mainstream to flow out from the second heat flow outlet 2, and wait until the high-temperature mainstream reaches the test requirement state and remains stable;

[0009] Step 4: Open the first transient heat flow switching plug plate 1 of the transient thermal response test section, and close the second transient heat flow switching plug plate 2, so that the high-temperature mainstream with stable temperature flows into the test section and flows out from the first heat flow outlet 1 of the test section, thereby providing transient convection heat transfer boundary conditions for the CMC flat plate component, and at the same time, use an infrared thermal imager to capture the temperature change law of the hot wall surface of the CMC flat plate component;

[0010] Step 5: After the high-temperature furnace is heated to a preset oxidation temperature, the test CMC material flat plate component is placed in the high-temperature furnace for a preset time, and the test CMC material flat plate component is taken out of the high-temperature furnace. The above steps are repeated multiple times for the test CMC material flat plate component after high-temperature oxidation to obtain the transient thermal response characteristics of the CMC components with different oxidation temperatures and different oxidation times.

[0011] Optionally, in one embodiment of the present invention, sealing strips are used for the first transient heat flow switching plug board 1 and the second transient heat flow switching plug board 2 to ensure that the high-temperature mainstream will not leak from the side outlet during the test.

[0012] Optionally, in one embodiment of the present invention, in step 5, the influence of the oxidation time on the thermal response characteristics of the CMC component is obtained by continuously superimposing the oxidation time at the same oxidation temperature for the same test CMC material flat component;

[0013] By carrying out high-temperature oxidation at different temperatures within the same oxidation time on flat components of different experimental CMC materials, the influence of oxidation temperature on the thermal response characteristics of CMC components can be obtained.

[0014] The transient convection heat transfer test method of a ceramic matrix composite material component under high temperature oxidation according to an embodiment of the present invention has the following beneficial effects:

[0015] 1) The present invention simulates the high temperature characteristics of the aircraft engine service environment through a high-temperature furnace. Compared with directly constructing an ultra-high temperature mainstream fuel gas environment, it is simpler and more efficient, and can accurately control the oxidation temperature and oxidation time, thereby being able to carry out quantitative analysis of the thermal response characteristics of CMC components under high-temperature oxidation.

[0016] 2) The present invention realizes the instantaneous switching of the high-temperature mainstream boundary of the CMC component by switching the transient heat flow switching plug-in board 1 and the transient heat flow switching plug-in board 2, and can efficiently and accurately control the high-temperature mainstream convection heat transfer boundary of the CMC high-temperature component, thereby providing accurate thermal boundary conditions for the thermal response analysis of the CMC component under high-temperature oxidation.

[0017] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0019] Figure 1 A flow chart of a transient convection heat transfer test method for a ceramic matrix composite component under high temperature oxidation provided according to an embodiment of the present invention;

[0020] Figure 2 A schematic diagram of a test device system according to an embodiment of the present invention;

[0021] Figure 3 A high temperature furnace for simulating an oxidizing environment according to an embodiment of the present invention;

[0022] Figure 4 A schematic diagram of a test section of an embodiment of the present invention;

[0023] Figure 5 The test section and CMC component surface temperature test photos of the embodiment of the present invention;

[0024] Figure 6 The following are photos of CMC components used in the test of the embodiment of the present invention and schematic diagrams of their dimensions;

[0025] Figure 7 The average temperature curve of the hot wall surface at different oxidation times according to the embodiment of the present invention;

[0026] Figure 8 1 is the average temperature curve of the hot wall surface at different oxidation temperatures in an embodiment of the present invention. DETAILED DESCRIPTION

[0027] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0028] Figure 1 The present invention is a flowchart of a method for testing transient convection heat transfer of a ceramic matrix composite material component under high temperature oxidation according to an embodiment of the present invention.

[0029] like Figure 1 As shown, the transient convection heat transfer test method of ceramic matrix composite components under high temperature oxidation includes the following steps:

[0030] Step 1: Based on the representative characteristics of the CMC material flat plate component, measure the mass, equivalent thermal conductivity, and thermal diffusion coefficient of the CMC material flat plate component;

[0031] Step 2: Install the test CMC material flat plate component on the transient thermal response test section, which has two high-temperature mainstream outlets regulated by transient heat flow switching plugs. During the experiment, adjust the cold flow in the transient thermal response test section channel to reach the test setting and maintain stability;

[0032] Step 3: Open the second transient heat flow switching plug plate 2 of the transient thermal response test section, close the first transient heat flow switching plug plate 1, open the air supply system to allow the high-temperature mainstream to flow out from the second heat flow outlet 2, and wait until the high-temperature mainstream reaches the test requirement state and remains stable;

[0033] Step 4: Open the first transient heat flow switching plug plate 1 of the transient thermal response test section, and close the second transient heat flow switching plug plate 2, so that the high-temperature mainstream with stable temperature flows into the test section and flows out from the first heat flow outlet 1 of the test section, thereby providing transient convection heat transfer boundary conditions for the CMC flat plate component, and at the same time, use an infrared thermal imager to capture the temperature change law of the hot wall surface of the CMC flat plate component;

[0034] Step 5: After the high-temperature furnace is heated to a preset oxidation temperature, the test CMC material flat plate component is placed in the high-temperature furnace for a preset time, and the test CMC material flat plate component is taken out of the high-temperature furnace. The above steps are repeated multiple times for the test CMC material flat plate component after high-temperature oxidation to obtain the transient thermal response characteristics of the CMC components with different oxidation temperatures and different oxidation times.

[0035] Optionally, in one embodiment of the present invention, sealing strips are used for the first transient heat flow switching plug board 1 and the second transient heat flow switching plug board 2 to ensure that the high-temperature mainstream will not leak from the side outlet during the test.

[0036] Optionally, in one embodiment of the present invention, in step 5, the influence of the oxidation time on the thermal response characteristics of the CMC component is obtained by continuously superimposing the oxidation time at the same oxidation temperature for the same test CMC material flat component;

[0037] By carrying out high-temperature oxidation at different temperatures within the same oxidation time on flat components of different experimental CMC materials, the influence of oxidation temperature on the thermal response characteristics of CMC components can be obtained.

[0038] The technical solution of the present invention is described in detail below in conjunction with the accompanying drawings and embodiments.

[0039] Example: Experiment on transient flow and heat transfer characteristics of ceramic matrix composite components under high temperature oxidation.

[0040] The test system consists of two parts. The first part is mainly composed of a high-temperature oxidation device and a thermophysical property testing equipment, which is used to provide a high-temperature oxidation simulation environment and thermophysical property parameter testing for CMC materials. The second part consists of a gas supply system, a signal measurement and acquisition system, and a test section, which is used to test the transient thermal response characteristics of CMC components under high-temperature airflow convection heat transfer conditions. The high-temperature oxidation device mainly includes a high-temperature furnace, the thermophysical property testing equipment includes a laser thermal conductivity tester, the gas supply system includes an air compressor, a flow meter, a heater, etc., the signal measurement and acquisition system includes temperature and pressure sensors and a signal acquisition instrument, and the test section includes a high-temperature mainstream, a low-temperature secondary flow channel, and a CMC material test piece. In the test section, the transient convection heat transfer boundary conditions on the surface of the CMC material test piece are realized through a transient heat flow switching plug-in, and an infrared thermal imager is used to obtain the thermal response law of the CMC component surface. The entire test system is like Figure 2 shown.

[0041] The high temperature oxidation system is mainly composed of the Kane KNPL-W1000 high temperature furnace ( Figure 3 The maximum operating temperature is 1650°C, the heating rate is 10°0C / min, and the constant temperature accuracy is 1±°C. The thermal physical property test system includes a laser thermal conductivity tester with a test range of 0.1W / (m·K) to 2000W / (m·K), which is used to test the thermal diffusivity and specific heat capacity of the sample.

[0042] In the hot flow air supply system of this test, after the air flow is generated by the air compressor, it first flows into the pressure-stabilizing gas storage tank to ensure the stability of the subsequent air flow rate. Then the air flow flows through the throttle valve to control it to the required flow rate, and then passes through the vortex flowmeter to enter the electric heater with a rated power of 200kW. Through temperature feedback control, the mainstream air flow reaches the temperature required for the test. The heated high-temperature gas can enter the test section after passing through the rectification section. After the cold flow is generated by the air compressor, it first flows into the pressure-stabilizing gas storage tank to ensure the stability of the subsequent cold flow rate. Then the air flow flows through the throttle valve to control it to the required flow rate, and then passes through the vortex flowmeter, and finally enters the test section through the rectification section.

[0043] The cross-sectional dimensions of the hot flow channel in the test section are 140mm×100mm, the cross-sectional dimensions of the cold flow channel are 60mm×60mm, and the dimensions of the test plate are 60mm×36mm. The back of the test plate is flush with the wall of the cold flow channel, and the front of the test plate is flush with the wall of the hot flow channel. Finally, the three form a whole. There is a transient hot flow switching plug and a hot flow standby outlet (hot flow outlet 2) upstream of the hot flow experimental section. During the experiment, first open the transient hot flow switching plug 2, and close the transient hot flow switching plug 1, so that the heat flow flows out from the hot flow outlet 2. After the heat flow reaches the test requirement state and remains stable, open the transient hot flow switching plug 1, and close the transient hot flow switching plug 2, so that the heat flow flows into the test section and flows out from the hot flow outlet 1, thereby providing transient heat flow; the schematic diagram of the test section is shown as follows Figure 4 as shown in .

[0044] The temperature of the CMC plate in contact with the heat flux wall was measured using a FLIR A655 infrared thermal imager. Figure 5 As shown in . The resolution of the temperature field captured by the thermal imager is 640×480, the maximum frame rate (full window) during dynamic shooting is 200Hz, and the spatial resolution is 1.36mrad. When using an infrared thermal imager to measure temperature, the temperature tested by the infrared thermal imager is affected by comprehensive factors such as the radiation characteristics of the test object itself (surface morphology, emissivity), the shooting environment, and the transmittance of the shooting window. The characteristic temperature on the hot wall surface is measured by a high-precision K-type thermocouple. The measured values ​​of the two at different temperatures are linearly fitted to obtain the fitting relationship between the two to calibrate the temperature measured by the infrared thermal imager, as shown in Figure 6 as shown in .

[0045] Figure 7The average temperature curve of the hot wall surface of the CMC plate after oxidation at 1373K for different time periods is given in the figure. After reaching steady state, the average temperature of the hot wall surface increased by 0.48% and 1.04% after 2h and 6h of oxidation, respectively, compared with that before oxidation. In the transient thermal response process, after 2h and 6h of oxidation, the average temperature of the hot wall surface was 338.21K and 342.46K (thermal response time was 60s), respectively, which increased by 1.33% and 2.60% compared with that before oxidation. It can be seen that the effect of high temperature oxidation on the transient temperature of the CMC plate is greater than its effect on the steady-state temperature.

[0046] Figure 8 The average temperature change curve of the hot wall at different oxidation temperatures is given in the figure. It can be seen from the figure that when the oxidation temperatures are 873K, 1073K and 1373K respectively, the average temperatures of the hot wall after reaching a steady state after 6h of oxidation are 346.42K, 3483.83K and 351.16K respectively; the change in the transient thermal response characteristics of the plate caused by the change in oxidation temperature is similar to the effect of oxidation time on the thermal response characteristics of the plate, because higher oxidation temperatures and longer oxidation times will reduce the thermal conductivity of the yarn, thereby bringing about changes in the transient thermal response characteristics.

[0047] Based on the transient flow heat transfer characteristics test method established in the present invention, it is possible to carry out transient flow heat transfer characteristics test research on CMC material components under high-temperature oxidation characteristic environments, obtain the thermal response characteristics and change laws of CMC material components under different oxidation temperatures and times, and provide a principle test verification method for the analysis model for the application of CMC material components in aerospace high-temperature components.

[0048] According to the transient convection heat transfer test method for ceramic matrix composite components under high-temperature oxidation proposed in an embodiment of the present invention, a transient flow heat transfer characteristics test method is established, which can carry out transient flow heat transfer characteristics test research under a high-temperature oxidation characteristic environment for CMC material components, obtain the thermal response characteristics and change laws of CMC material components under different oxidation temperatures and times, and provide a principle test verification method of the analysis model for the application of CMC material components in aerospace high-temperature components.

[0049] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or N embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0050] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "N" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0051] Any process or method description in a flowchart or otherwise described herein may be understood to represent a module, fragment or portion of code comprising one or N executable instructions for implementing the steps of a custom logical function or process, and the scope of the preferred embodiments of the present invention includes alternative implementations in which functions may not be performed in the order shown or discussed, including performing functions in a substantially simultaneous manner or in reverse order depending on the functions involved, which should be understood by technicians in the technical field to which the embodiments of the present invention belong.

Claims

1. A transient convection heat transfer test method for ceramic matrix composite components under high temperature oxidation, characterized in that: The following steps are involved: Step 1: Based on the representative characteristics of the CMC material flat plate component, measure the mass, equivalent thermal conductivity, and thermal diffusion coefficient of the CMC material flat plate component; Step 2: Install the test CMC material flat plate component on the transient thermal response test section, which has two high-temperature mainstream outlets regulated by transient heat flow switching plugs. During the experiment, adjust the cold flow in the transient thermal response test section channel to reach the test setting and maintain stability; Step 3: Open the second transient heat flow switching plug plate 2 of the transient thermal response test section, close the first transient heat flow switching plug plate 1, open the air supply system to allow the high-temperature mainstream to flow out from the second heat flow outlet 2, and wait until the high-temperature mainstream reaches the test requirement state and remains stable; Step 4: Open the first transient heat flow switching plug plate 1 of the transient thermal response test section, and close the second transient heat flow switching plug plate 2, so that the high-temperature mainstream with stable temperature flows into the test section and flows out from the first heat flow outlet 1 of the test section, thereby providing transient convection heat transfer boundary conditions for the CMC flat plate component, and at the same time, use an infrared thermal imager to capture the temperature change law of the hot wall surface of the CMC flat plate component; Step 5: After the high-temperature furnace is heated to a preset oxidation temperature, the test CMC material flat plate component is placed in the high-temperature furnace for a preset time, and the test CMC material flat plate component is taken out of the high-temperature furnace. The above steps are repeated multiple times for the test CMC material flat plate component after high-temperature oxidation to obtain the transient thermal response characteristics of the CMC components with different oxidation temperatures and different oxidation times.

2. The method according to claim 1, characterized in that In step 3 and step 4, sealing strips are used for the first transient heat flow switching plug board 1 and the second transient heat flow switching plug board 2 to ensure that the high-temperature mainstream will not leak from the side outlets during the test.

3. The method according to claim 1, characterized in that In step 5, the influence of oxidation time on the thermal response characteristics of the CMC component is obtained by continuously superimposing oxidation time at the same oxidation temperature for the same test CMC material flat component; By carrying out high-temperature oxidation at different temperatures within the same oxidation time on flat components of different experimental CMC materials, the influence of oxidation temperature on the thermal response characteristics of CMC components can be obtained.

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