CN-121977787-A - Gas-solid interface unbalanced reaction analysis method for SiC-based heat-resistant material under high enthalpy

CN121977787ACN 121977787 ACN121977787 ACN 121977787ACN-121977787-A

Abstract

The invention provides a method for analyzing a gas-solid interface imbalance reaction of a SiC-based heat-resistant material under high enthalpy, which mainly comprises the steps of (1) constructing a multi-physical-field coupling thermal environment by utilizing a high enthalpy plasma wind tunnel through regulating flow field parameters, structures and material surface reaction conditions, and (2) cooperatively applying four spectroscopic diagnosis technologies of radiation spectrum, narrow-band imaging spectrum, laser absorption spectrum and infrared radiation, and extracting the correlation characteristics of macroscopic thermal response and near-wall flow of the surface of the SiC-based composite ceramic material through synchronously measuring the multi-physical-quantity space-time distribution of the near-wall flow field of the SiC-based composite ceramic material, so that the system reveals the catalytic-oxidation-nitridation competitive coupling rule in the gas-solid interface imbalance reaction of the SiC-based material under long-term high enthalpy. The invention can provide multidimensional analysis for gas-solid interface unbalanced reaction mechanism research, and can realize fine simulation and quantitative characterization of multi-field coupling phenomena such as passive oxidation, active oxidation, passive/active oxidation transition and the like.

Inventors

LIN XIN
FU YIFAN
WANG ZEZHONG
WU XINGYU
ZHENG YUTING

Assignees

中国科学院力学研究所

Dates

Publication Date: 20260505
Application Date: 20260210

Claims (10)

1. The analysis method for the gas-solid interface non-equilibrium reaction of the SiC-based heat-resistant material under high enthalpy is characterized by mainly comprising the following steps of: (1) Based on the SiC-based composite ceramic material, a high-enthalpy plasma wind tunnel is utilized, and a multi-physical-field coupling thermal environment is constructed by regulating and controlling the parameters of a plasma wind tunnel flow field, the structure and the surface reaction conditions of the material; (2) Then, by cooperatively applying four spectroscopic diagnosis technologies of radiation spectrum, narrow-band imaging spectrum, laser absorption spectrum and infrared radiation, and synchronously measuring a plurality of physical quantities distributed in a near-wall flow field of the SiC-based composite ceramic material in a space-time manner, the correlation characteristics of macroscopic thermal response and near-wall flow of the surface of the SiC-based composite ceramic material are extracted, and then the system reveals a catalytic-oxidation-nitridation competitive coupling rule in a non-equilibrium reaction of a gas-solid interface of the SiC-based material under long-term high enthalpy.
2. The analysis method of the gas-solid interface unbalance reaction of the SiC-based heat protection material under high enthalpy according to claim 1, wherein the step (1) is to construct a multi-physical field coupling heat environment with a typical boundary layer structure, different oxidation characteristics and a high-temperature air heating environment as basic elements by utilizing a high-enthalpy plasma wind tunnel, specifically, by regulating the incoming enthalpy value, pressure and components of a plasma wind tunnel flow field to form high-temperature reaction air flow, adjusting a spray pipe structure for regulating the beam spot size, flow rate or energy distribution of a plasma jet and the installation state of a measured heat protection material sample to construct a typical boundary layer flow structure, and controlling the surface temperature and the environment atmosphere of the measured heat protection material sample to induce different oxidation characteristics.
3. The analysis method for the gas-solid interface unbalance reaction of the SiC-based heat-resistant material under the high enthalpy according to claim 2 is characterized in that the Gao Han plasma wind tunnel is an arc wind tunnel or a radio frequency or high frequency plasma wind tunnel, and the simulated enthalpy value is more than 10 MJ/kg.
4. The method for analyzing the gas-solid interface unbalance reaction of the SiC-based heat-resistant material under high enthalpy according to claim 2, wherein the typical boundary layer structure is mainly divided into two types of standing point compression flow and deformation structure shear flow; the different oxidation features are passive oxidation, active oxidation, and passive-active oxidation transition states.
5. The method for analyzing the gas-solid interface unbalance reaction of the SiC-based heat-resistant material under high enthalpy according to claim 2, wherein the construction basis of the different oxidation characteristics is determined by comprehensively considering the surface temperature and the back surface temperature in the material ablation process, the microcosmic morphology components of the surface or the section after ablation, and the multi-parameter data of the dynamic change characteristics of the radiation spectrum represented by near-wall ablation products Si, siO, CN or N 2 + .
6. The method for analyzing the gas-solid interface imbalance reaction of the SiC-based heat-resistant material under high enthalpy according to claim 1, wherein the radiation spectrum technology in the step (2) is to clearly ablate the product components by measuring the ultraviolet-visible-near infrared band radiation spectrum, and the purposes mainly include three points: ① Obtaining unbalanced temperature parameters at least comprising vibration temperature and rotation temperature by analyzing the spectrum information; ② Judging whether active oxidation and nitridation reactions exist or not through spectral component characteristics of an ablation product, taking the radiation intensity of the corresponding ablation product as a characteristic quantity of the reaction degree, and determining the intensity of the reaction through analyzing the change of the radiation intensity; ③ Guiding narrow-band spectral imaging to select corresponding optical filters.
7. The method for analyzing the gas-solid interface unbalance reaction of the SiC-based heat-resistant material under the high enthalpy according to claim 1 is characterized in that the narrow-band imaging spectrum technology in the step (2) mainly comprises a narrow-band filter aiming at ablative radiation characteristics and a high-speed camera, the center wavelength and the bandwidth of the narrow-band filter are determined according to radiation spectrum, and the visualization of the gas-solid interface reaction area is realized according to model bypass narrow-band imaging spectrum images on the one hand, and the design of the radiation spectrum technology and the absorption spectrum technology light path is guided on the other hand.
8. The method for analyzing the gas-solid interface unbalance reaction of the SiC-based heat-resistant material under the high enthalpy according to claim 1, wherein the laser absorption spectrum technology in the step (2) can be used for measuring the translational temperature and the component density of atoms or generated molecules participating in the gas-solid interface reaction at different axial positions on the surface of the material, and is used for quantitatively analyzing the consumption characteristics of reactive components and the ablation behavior of the material in the unbalance reaction competition process, the measuring position of the laser absorption spectrum is determined according to the narrow-band imaging spectrum result, at least two paths of synchronous measurement are ensured, one path passes through a region capable of intuitively reflecting the intensity of the gas-solid interface reaction for the unbalance reaction analysis, and the other path is the edge of a reaction zone and is used for monitoring the incoming flow condition.
9. The method for analyzing the gas-solid interface unbalance reaction of the SiC-based heat-resistant material under the high enthalpy of claim 1, wherein the surface macroscopic thermal response of the SiC-based composite ceramic material comprises the surface temperature and the back surface temperature in the ablation test process, and further comprises the microscopic morphology and the element composition of the surface or the cross section after the ablation.
10. The method for analyzing the gas-solid interface unbalance reaction of the SiC-based heat-resistant material under high enthalpy according to claim 1 is characterized in that the method for extracting the correlation characteristics of the macroscopic thermal response of the material surface and the near-wall flow is characterized in that the change rules of the near-wall flow and the reaction characterization parameters such as radiation characteristics, translation temperature, component density and the like are subjected to time synchronization comparison analysis by definitely taking the surface and back temperature change curves as reference objects so as to extract the correlation characteristics between the macroscopic thermal response of the material and the near-wall flow state.

Description

Gas-solid interface unbalanced reaction analysis method for SiC-based heat-resistant material under high enthalpy Technical Field The invention relates to the technical field of hypersonic aircraft aerodynamic heat protection research, in particular to a method for analyzing unbalanced reaction of a gas-solid interface of a SiC-based heat-resistant material under high enthalpy. Background The SiC-based ceramic composite material, such as C f/SiC、SiCf/SiC、ZrB2 -SiC, is one of the main material systems adopted by the current high-speed aircraft by virtue of the characteristics of high hardness, high specific strength, high melting point, high wear resistance and the like. The anti/non-ablative characteristic of the SiC-based material is achieved by effectively slowing down the diffusion rate of oxygen/nitrogen atoms and inhibiting the deep oxidation of the material due to a condensed phase protection layer such as compact SiO 2、B2O3 generated by surface oxidation. With the development of various novel aerospace vehicles, new layout characteristics and service environments determine that the aerodynamic heat environment is more complex, but the key parameter characterization technology and the corresponding test system for the heat resistance of the SiC-based material in the high-enthalpy long-term environment are extremely lacking currently. When the aerospace vehicle reenters the atmosphere, the coupling competition effect of the high enthalpy incoming flow and the unbalanced reactions such as catalytic recombination, oxidation, nitridation and the like of the heat-resistant material at the gas-solid interface is an important factor influencing the aerodynamic heat environment. Taking catalysis as an example, the process of exciting high enthalpy dissociation oxygen and nitrogen atoms to participate in surface catalysis composite reaction by the heat-proof material is described, so that not only can heat load be aggravated through chemical heat release, but also the oxidation rate of the material can be influenced. Meanwhile, the oxidation reaction of the material surface not only can form new solid phase components on the material surface to change the physical parameters (such as structure, components, roughness and the like) of the surface so as to further bring about the change of the catalytic property, but also can form new gas phase particles to enter a flow field to change the fluid characteristics. In addition, studies have demonstrated that the role of nitrogen atoms in high enthalpy nitrogen rich environments is not negligible, and that they participate in gas-solid interface chemical reactions through nitridation or catalytic recombination, leading to boundary layer temperature increases and exacerbating surface thermal loading. Therefore, the correct cognition of the imbalance reaction law of the gas-solid interface is significant for the prediction of the change law of the thermal load of the aircraft and the development of the thermal protection technology. In the aspect of experimental research, a high-enthalpy wind tunnel which effectively simulates an extreme aerodynamic heat environment is taken as a test platform, and the method for measuring the surface heat flux density of a material, monitoring the surface temperature change in ablation and analyzing the microcosmic morphology components before and after the material ablation is a main technical means of the research in the field at present, so that good technical accumulation is realized at home and abroad. Taking research on catalytic properties as an example, the principle is that a material with known catalytic properties is referenced, the net heat flow of the material to be detected is analyzed, and the association between dissociation energy in a boundary layer and the catalytic properties of the surface in an object plane is utilized to calculate and obtain the catalytic composite coefficient. It should be noted that, in view of the extremely sensitive catalytic effect to flow field components, high-frequency plasma wind tunnel test systems without electrode ablation pollution are widely adopted internationally. In an objective way, the high-frequency plasma wind tunnel can effectively simulate the thermal environment of the reentry vehicle, and the material ablation data of the high-frequency plasma wind tunnel also strongly supports the development of the high-enthalpy reentry vehicle technology in China. However, due to the fact that the conventional experimental method lacks key process parameters in the multi-field coupling process, particularly the density of components in a boundary layer, the vibration temperature and the like, the cognition on core scientific problems such as a gas-solid interface unbalanced reaction competitive coupling mechanism and the like still lags behind engineering practice, so that the typical contradiction between engineering application feasibility and insufficient mechanism cognition exists