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A deep understanding of surface catalysis recombination characteristics is significant for accurately predicting the aeroheating between hypersonic non-equilibrium flow and thermal protection materials, while a de-coupling sensitivity analysis of various influential factors is still lacking. A gas–solid interface (GSI) model with a hyperthermal flux boundary was established to investigate the surface catalysis recombination mechanisms on nanoscale silica surfaces. Using the reactive molecular dynamics (RMD) simulation method, the effects of solid surface temperature, gas incident angle, and translational energy on the silica surface catalysis recombination were qualified under hyperthermal atomic oxygen (AO), atomic nitrogen (AN), and various AN/AO gas mixtures’ influence. It can be found that, though the Eley–Rideal (E–R) recombination mechanism plays a dominant role over the Langmuir–Hinshelwood (L–H) mechanism for all the sensitivity analyses, a non-linear increasing pattern of AO recombination coefficient γO2 with the increase in incident angle θin and translational energy Ek is observed. Compared with the surface catalysis under hyperthermal AO impact, the AN surface adsorption fraction shows an inverse trend with the increase in surface temperature, which suggests the potential inadequacy of the traditional proportional relationship assumptions between the surface adsorption concentration and the surface catalysis recombination coefficient for other species’ impact instead of AOs. For the incoming bi-component AO/AN gas mixtures, the corresponding surface catalysis coefficient is not the simple superposition of the effects of individual gases but is affected by both the intramolecular bond energies (e.g., O2, N2) and intermolecular energies (e.g., Si/N, Si/O).

An anisotropic design is introduced to the laminated damped plates in this paper. The parameter effects on the loss factor of anisotropic laminated damped plates have been analyzed in detail. The damping analyses and control mechanism of laminated anisotropic damped plates have been carried out theoretically. Finally, through the software developed here, the parameter optimization has been conducted on the loss factors of the anisotropic laminated damped plates. The results indicate it may provide scientific basis for the new optimization anisotropic design of laminated damped plates used in Aircraft cabin structure for obtaining the maximum loss factor.

Thermal protection system (TPS) is essential for the safe and reliable flying of any high-speed aircraft. Carbon fiber-reinforced phenolic resin (PR) composite is one of the most important matrix candidates for ablative materials, the microscopic understanding of the pyrolysis process of PR, however, still remains poor. The usual numerical approach is based on volumetric pyrolysis while neglecting the influence of external hyperthermal surrounding. A surface-volume coupled reactive molecular dynamics (RMD) model is established in this work to simulate complicated heat /mechanics /chemistry multi-physical field coupled pyrolysis problem. The pyrolysis process of carbon fiber-PR composite is investigated in the presence of vacuum and hyperthermal gas impacts, and compared with the volumetric pyrolysis simulation only. The consideration of the surface-volume coupling reveals many unique features beyond the volumetric pyrolysis, which include the generation of different pyrolysis products and the dependence of the effective mass diffusivity of pyrolysis gases on impinging gases in the presence of hyperthermal non-equilibrium environment. With detailed revelation of the evolutions of PR solid phase and pyrolysis gaseous products, the work is of great help in improving the microscopic pyrolysis mechanisms, especially the 'blowing gas effect', a key phenomenon for improved understanding of the complicated hypersonic boundary layer flow.