C / sic material multilayer thermal protection structure force-thermal coupling analysis test system and method

Abstract

The application discloses a C / SiC material multilayer thermal protection structure force-thermal coupling analysis test system and method, which comprises a thermal load simulation module, a pressure load simulation module, a data acquisition module and a test piece. The thermal load simulation module is warmed up by signal control transformer power output; a thermocouple is used to measure the temperature distribution of the innermost inner wall surface of the test piece during radiation heating, so that the thermal boundary condition of the test piece is obtained; the pressure load module is simulated by placing loads with different masses above the test piece; and the data acquisition module collects deformation data of the test piece under the action of force-thermal coupling and temperature distribution data of the outer wall surface of the rigid aerogel layer of the test piece. The application can obtain the distribution characteristics and variation rules of the temperature field and the strain field of the multilayer thermal protection structure under different pressure loads and different temperature loads, and provides a principle test verification method for the analysis model of the ceramic matrix composite multilayer thermal protection structure.

Description

Technical Field

[0001] This invention belongs to the field of engineering thermophysics technology, and specifically relates to a test system and method for force-thermal coupling analysis of multilayer thermal protection structures of C / SiC materials. Background Technology

[0002] The combustion temperature of advanced ramjet engines can reach over 2500K, and the temperature of the combustion chamber walls exceeds 2000K, requiring effective thermal protection structures to ensure the safe operation of the combustion chamber and its nozzle extension. The thermal protection structure of a ramjet engine combustion chamber often employs a multi-layered material structure, including a heat-resistant layer, a load-bearing layer, a heat-insulating layer, and an outer shell along the radial direction from the inside out. The innermost heat-resistant layer directly bears the extremely high temperature of the combustion gases within the combustion chamber, placing stringent requirements on its temperature resistance. C / SiC ceramic matrix composites, with their superior properties such as high specific strength, high specific modulus, high temperature resistance, and ablation resistance, have been widely used in engine combustion chambers. Compared to the refractory metal materials previously used in engine combustion chambers, C / SiC composites offer the following advantages: no cooling system is required, simplifying engine structural design; high specific strength and specific stiffness (density is 1 / 4 to 1 / 3 that of refractory metals), good thermal shock resistance and creep resistance; improved operating temperature; and better oxidation resistance. The United States, Germany, France, my country, and Japan have all vigorously carried out research on the preparation and application of C / SiC composite materials, which has led to the widespread use of C / SiC composite materials as materials for engine combustion chambers and nozzle extension sections.

[0003] For multilayer thermal protection structures made of ceramic matrix composites, the temperature distribution and structural deformation exhibit complex, non-uniform, and nonlinear characteristics due to the different physical properties of each layer and the varying force-thermal loads along the engine's axial, radial, and circumferential directions. Therefore, it is necessary to establish a force-thermal coupling analysis model for these multilayer thermal protection structures, analyze their force-thermal coupling response characteristics, and conduct corresponding matching design studies. A key issue to address is ensuring the accuracy of the force-thermal coupling analysis model for these structures, thereby providing a powerful analytical tool for force-thermal coupling response characteristic analysis and matching design. Therefore, this invention addresses the accuracy verification requirements of the force-thermal coupling analysis model for multilayer thermal protection structures made of ceramic matrix composites by exploring simulation and characterization methods for thermal and pressure loads on the thermal protection structure. A principle-based experimental method for the force-thermal coupling response characteristics of multilayer thermal protection structures made of ceramic matrix composites is established, providing a principle-based verification platform for the force-thermal coupling analysis model of multilayer thermal protection structures. Summary of the Invention

[0004] To investigate the thermal distribution and structural deformation characteristics of a multi-layer thermal protection structure in an engine combustion chamber under force-thermal coupling conditions, this invention provides a force-thermal coupling analysis test system and method for C / SiC material multi-layer thermal protection structures. The test system simulates the thermal and pressure load environments of an engine combustion chamber and conducts force-thermal coupling characteristic experiments on typical multi-layer thermal protection structure unit model specimens.

[0005] To achieve the above-mentioned technical objectives, the technical solution of the present invention is as follows:

[0006] The C / SiC material multilayer thermal protection structure force-thermal coupling analysis test system includes a test specimen, a thermal load simulation module, a pressure load simulation module, and a data acquisition module;

[0007] The test specimen is a multi-layer thermal protection structure, which includes a ceramic matrix composite thermal protection plate and a rigid aerogel insulation plate.

[0008] The thermal load simulation module heats the test piece by thermal radiation through an electrically heated ceramic resistance plate.

[0009] The pressure load simulation module simulates pressure load by placing weights of different masses above the test piece.

[0010] The data acquisition module acquires temperature and pressure load data on the inner and outer surfaces of the test piece, as well as temperature distribution and deformation data on the outer surface of the test piece under force-thermal load coupling conditions.

[0011] Preferably, in the thermal load simulation module, the electrically heated ceramic resistance plate is connected to a transformer, and the inner surface of the test piece is also provided with a feedback thermocouple to collect the temperature of the inner surface of the test piece.

[0012] Preferably, in the pressure load simulation module, when weights of different masses are placed on the outer surface of the test piece, the stage support is installed only at the center of the test piece to avoid the weights of different masses affecting the temperature and deformation measurement of the outer surface of the test piece.

[0013] Preferably, in the data acquisition module, all data is acquired through non-contact measurement methods.

[0014] Preferably, the temperatures of the inner and outer surfaces of the test specimen, as well as the temperature of the outer surface of the test specimen under force-thermal load coupling conditions, are obtained by an infrared thermal imager temperature testing system; the deformation data of the test specimen are obtained by a Dom Optics digital image strain testing system.

[0015] The experimental method for force-thermal coupling analysis of C / SiC multilayer thermal protection structures includes the following steps:

[0016] 1) Obtain test specimens;

[0017] 2) Construct a test system, which includes a test specimen, a thermal load simulation module, a pressure load simulation module, and a data acquisition module;

[0018] 3) The test specimen is tested using the test system to obtain the temperature distribution and deformation data of the outer surface of the test specimen under force-thermal load coupling conditions.

[0019] The beneficial effects of adopting the above technical solution are as follows:

[0020] (1) The present invention simulates the thermal load environment of the multi-layer thermal protection structure unit component of the engine combustion chamber through the thermal load simulation module and the pressure load simulation module. It can accurately control the temperature load and pressure load, and thus accurately extract the temperature and pressure boundary data of the multi-layer thermal protection structure under the test conditions, which can be used as the boundary conditions of the force-thermal coupling analysis model of the multi-layer thermal protection structure of the engine combustion chamber.

[0021] (2) In this invention, the data acquisition module uses a non-contact Dom optical digital image testing system to obtain the strain distribution characteristics of the test piece surface. Compared with the strain gauge electrical measurement method, this strain testing system can extract the strain data of the target area in the test piece, and there is no influence of surface temperature change on the strain data. In this invention, the data acquisition module uses an infrared thermal imager to obtain the surface temperature distribution of the test piece, which can more realistically and effectively obtain the overall temperature distribution characteristics of the test piece surface. This provides data support for the study of the temperature field and strain field distribution characteristics of the multi-layer thermal protection structure of the engine combustion chamber. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the experimental device structure of the present invention;

[0023] Figure 2 It is a temperature distribution cloud map obtained by an infrared thermal imager;

[0024] Figure 3 The stress distribution cloud map is obtained by taking pictures and calculating using the DIC non-contact strain measurement system. Implementation

[0025] The technical solution of the present invention will be described in detail below with reference to the accompanying drawings and embodiments.

[0026] Example: Principle test of the force-thermal coupling response characteristics of a multilayer thermal protection structure made of ceramic matrix composites.

[0027] The experimental system includes a thermal load simulation module, a pressure load simulation module, a data acquisition module, and a test specimen. The test specimen is fixed to the base using clamps. The thermal load simulation module raises the temperature via signal-controlled voltage. A heating ceramic plate in the system heats the test specimen radiantly. Simultaneously, thermocouples measure the inner surface temperature of the test specimen and feed the signal back to the control box to achieve the set heating temperature. During the experiment, thermocouples combined with a heat flow meter are used to measure the temperature distribution and local heat flow value of the inner wall surface during radiant heating. The temperature and heat flow data are displayed on the data panels of the accompanying temperature monitoring instrument and heat flow meter to accurately obtain the thermal boundary conditions of the test specimen. The pressure load simulation module above the test specimen applies pressure loads to the specimen using standard weights of different masses, simulating the applied pressure load. The deformation data generated by the test specimen under force-thermal coupling conditions is collected by the strain testing system in the data acquisition module and stored in the accompanying software. The temperature distribution of the outer wall surface of the test specimen is acquired by an infrared thermal imager in the data acquisition system, and the experimental data is recorded. A schematic diagram of the experimental system is shown below. Figure 1 As shown.

[0028] The thermal load simulation module consists of a ceramic heating plate, a temperature feedback control box, and a test specimen fixing and mounting bracket. In this experimental study, the ceramic heating plate is used to simulate the heating effect of combustion gas on the multi-layered thermal protection structure of a multi-layered combustion chamber via radiant heating. The temperature feedback control box uses an operation panel to set a temperature and then uses high-voltage electricity to heat the ceramic heating plate, which in turn radiates heat to the test specimen. A temperature feedback thermocouple is installed in the center of the test specimen to monitor and provide feedback on the temperature of the entire inner wall surface. The temperature signal is converted into an electrical signal and fed back to the control box. When the temperature exceeds the set temperature, the control box cuts off the power.

[0029] The heating method used in the experiment was ceramic plate radiant heating. Compared to the actual environment of the passive thermal protection combustion chamber of a sub-fuel ramjet engine, it lacks the pressure load generated by the high-temperature airflow on the wall during combustion. Therefore, in this experiment, standard weights were added to the outer wall of the test piece. Different pressure loads were applied to the test piece by changing the mass of the weights. Since the green rigid aerogel layer is prone to breakage and failure under gravity loads, the rigid aerogel layer was removed when applying pressure loads, and the gravity load was applied directly to the C / SiC layer. The weights on the outer wall were designed to have masses of 10 kg, 15 kg, and 20 kg.

[0030] The temperature testing system consists of an infrared thermal imager, armored thermocouples, and a multi-channel temperature scanner. The temperature measuring instruments used in the experiment were a FLIR A615 infrared thermal imager, an MT-X multi-channel temperature scanner, and armored thermocouples as temperature measurement sensors. The FLIR A615 infrared thermal imager has a resolution of 640×480 pixels, a spatial resolution of 0.68 mrad, a wavelength range of 7.5-14 mm, a test temperature range of 300˚C to 2000˚C, and a test accuracy of ±2%. The thermocouples have a temperature measurement range of 0˚C to 1000˚C and a test accuracy of ±0.75%.

[0031] In this experiment, the Digital Image Measurement System (DIC testing system) from DOM Optical Technology Co., Ltd. was used to test the surface strain of the test specimen. DOM Optical's measurement systems are widely used in global industrial processes, and this testing system can meet various needs for specific applications such as vibration analysis, temperature correlation measurement, deformation tracking, expansion testing, tensile testing, and bending testing. This technology is an algorithm that compares correlated points in an image, allowing the calculation of surface displacement and strain distribution. The strain measurement range is 0.005% to 2000%, the strain measurement accuracy is 0.005%, and the test temperature range is -100℃ to 1500℃.

[0032] In the experiment, the ceramic matrix composite thermal protection plate, the rigid aerogel insulation plate, and their combined connection structure were fixed to the test chamber using bolt connections. The fixing base applied constraints to the four sides of the test chamber using clamps. The experiment was then conducted according to specific test conditions. The force load conditions were 0 kg, 10 kg, 15 kg, and 20 kg, and the temperature loads were 550℃, 650℃, and 750℃, thus simulating the influence of force-thermal coupling conditions on the test specimen under different temperature and pressure loads.

[0033] Turn on the power switches of the temperature simulation system and data acquisition system, calibrate each instrument, use the DIC non-contact strain measurement system to take images of the original test piece when it has not deformed, and record the deformation data.

[0034] When the test specimen is subjected to no pressure load and only the boundary temperature load: the temperature control box temperature is set to 550℃, 650℃, and 750℃ respectively. As the temperature rises, the thermocouple will provide temperature feedback on the heating temperature of the outer wall and the control box. When the heating temperature reaches the set temperature, the temperature of the thermocouple and the control box remains constant, and the test specimen is heated to maintain the temperature. After the test environment stabilizes, the stress and strain data of the test specimen surface under each working condition are obtained through the DIC non-contact strain measurement system, and the temperature distribution data of the test specimen surface under each working condition is obtained by infrared thermal imager.

[0035] When the test specimen is affected by temperature loads and different pressure loads: After completing the three working condition tests under no pressure load, the test specimen is subjected to a force-thermal coupling load test. After removing the rigid aerogel layer, the gravity load is directly applied to the C / SiC layer. Loads of 10 kg, 15 kg, and 20 kg are added to the outer layer respectively. At the same time, temperature loads of 550℃, 650℃, and 750℃ are applied to the test specimen respectively. After a period of heat preservation and heating, and after the test data stabilizes, the stress-strain data of the test specimen surface under each working condition is obtained through the DIC non-contact strain measurement system. The temperature distribution data of the test specimen surface under each working condition is obtained by infrared thermal imager. The results of the obtained temperature data are as follows: Figure 2 As shown, the stress imaging results are as follows: Figure 3 As shown.

[0036] Based on the principle-based experimental method established in this invention, force-thermal coupling characteristic experiments can be conducted on multilayer thermal protection structural plates of ceramic matrix composites. The distribution characteristics and variation laws of temperature field and strain field of multilayer thermal protection structure under different pressure loads and different temperature loads can be obtained, providing a principle-based experimental verification method for the application of multilayer thermal protection structure of ceramic matrix composites in high-temperature components of aerospace.

[0037] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A mechanical-thermal coupling analysis and testing system for multilayer thermal protection structures of C / SiC materials, characterized in that: It includes a test specimen, a thermal load simulation module, a pressure load simulation module, and a data acquisition module; The test specimen is a multi-layer thermal protection structure, which includes a ceramic matrix composite thermal protection plate and a rigid aerogel insulation plate. The thermal load simulation module heats the test piece by thermal radiation through an electrically heated ceramic resistance plate. The pressure load simulation module simulates pressure load by placing weights of different masses above the test piece. The data acquisition module acquires temperature and pressure load data on the inner and outer surfaces of the test piece, as well as temperature distribution and deformation data on the outer surface of the test piece under force-thermal load coupling conditions.

2. The force-thermal coupling analysis test system for C / SiC material multilayer thermal protection structures according to claim 1, characterized in that: In the thermal load simulation module, the electrically heated ceramic resistance plate is connected to a transformer, and the inner surface of the test piece is also equipped with a feedback thermocouple to collect the temperature of the inner surface of the test piece.

3. The force-thermal coupling analysis test system for C / SiC material multilayer thermal protection structures according to claim 1, characterized in that: In the pressure load simulation module, when weights of different masses are placed on the outer surface of the test piece, the stage support is installed only at the center of the test piece to avoid the weights of different masses affecting the temperature and deformation measurement of the outer surface of the test piece.

4. The force-thermal coupling analysis test system for C / SiC material multilayer thermal protection structures according to claim 1, characterized in that: In the data acquisition module, all data is acquired through non-contact measurement methods.

5. The force-thermal coupling analysis test system for C / SiC material multilayer thermal protection structures according to claim 4, characterized in that: The temperatures of the inner and outer surfaces of the test specimen, as well as the temperature of the outer surface of the test specimen under force-thermal load coupling conditions, were obtained by an infrared thermal imager temperature testing system; the deformation data of the test specimen were obtained by a Dom Optics digital image strain testing system.

6. A test method for force-thermal coupling analysis of multilayer thermal protection structures of C / SiC materials, characterized by: Includes the following steps: 1) Obtain test specimens; 2) Construct the test system as described in any one of claims 1-5; 3) The test specimen is tested using the test system to obtain the temperature distribution and deformation data of the outer surface of the test specimen under force-thermal load coupling conditions.

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