Guolin Wang, Liping Liu
Hypersonic Aerodynamics Institute,China Aerodynamics Research and Development Center 621000, Mianyang, Sichuan, China
EXTENDED ABSTRACT: Thermal protection ceramics have excellent thermochemical ablation properties due to their strong oxidation atmosphere and ultra-wide temperature range (≦3000K), and have become a new type of non-ablative thermal protection material developed by various aerospace countries. However, the universality and the failure mechanism of thermochemical ablation properties of thermal protection ceramic have become the main bottlenecks in the research and development of thermal protection ceramic.Based on the phenomena in the process of surface thermochemical ablation tests of thermal protection ceramic, this report analyzes the causes of the following four problems in detail: (1) The surface oxidation/ catalytic coupling has a greater impact on heat and mass transfer, which is derived from the thickness of the surface oxide layer and the evolution rate of phase state; (2) The lack of theoretical closure and characterization uniqueness of the finite rate model of heterogeneous reaction is caused by the lack of in-depth understanding of the theoretical basis of experimental characterization and the failure to effectively decouple the experimental data during data analysis; (3) The density of the oxide layer on the surface of non-oxide ceramics is the most important factor to improve its oxidation resistance, and it is impossible to reliably evaluate the advantages and disadvantages of its antioxidant performance due to the lack of corresponding theoretical models and criteria for the characterization and definition of the dense oxide layer; (4) The essence of the failure of the antioxidant performance of non-oxide ceramics is the depletion of its surface dense oxide layer. Due to the lack of an effective model for the characterization of the dense oxide layer loss process, it only relies on the simulation test with large limitations. On this basis, we try to effectively solve the above four bottleneck problems from the two levels of theory and method, and put forward some suggestions, which may play a role in improving the research and development and application capabilities of China's thermal protection ceramic.
Keywords: non-ablation thermal materials; thermal chemical ablation properties; oxidation / catalytic characterization; thermal failure.
Brief introduction: Wang Guolin, Ph.D., researcher, master supervisor, professional chief engineer of Hypersonic Aerodynamics Institute of China Aerodynamics Research and Development Center, member of the High Temperature Gases Professional Committee of the Aerodynamic Society and the Editorial Board of the Journal of Experimental Fluid Mechanics. Mainly engaged in high-enthalpy chemical non-equilibrium flow and thermal protection materials coupled heat transfer and mass transfer, high enthalpy plasma test simulation device and thermal protection materials simulation theory and experimental research. He has undertaken more than 40 related research projects, won 4 provincial and ministerial science and technology progress awards, more than 20 invention patents, and published more than 20 journal papers. It has advocated and initiated a seminar on the coupling of hypersonic flow and thermal protection materials with high academic standards in the industry, and promoted the exchange and cooperation between domestic counterparts in this field.