A new surface catalytic model for silica-based thermal protection material for hypersonic vehicles

https://doi.org/10.1016/j.cja.2015.08.011Get rights and content
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Abstract

Silica-based materials are widely employed in the thermal protection system for hypersonic vehicles, and the investigation of their catalytic characteristics is crucially important for accurate aerothermal heating prediction. By analyzing the disadvantages of Norman’s high and low temperature models, this paper combines the two models and proposes an eight-reaction combined surface catalytic model to describe the catalysis between oxygen and silica surface. Given proper evaluation of the parameters according to many references, the recombination coefficient obtained shows good agreement with experimental data. The catalytic mechanisms between oxygen and silica surface are then analyzed. Results show that with the increase of the wall temperature, the dominant reaction contributing to catalytic coefficient varies from Langmuir–Hinshelwood (LH) recombination (TW < 620 K) to Eley–Rideal (ER) replacement (620 K < TW < 1350 K), and then to O2 desorption (TW > 1350 K). The surface coverage of chemisorption areas varies evidently with the dominant reactions in the high temperature (HT) range, while the surface coverage of physisorption areas varies within quite low temperature (LT) range (TW < 250 K). Recommended evaluation of partial parameters is also given.

Keywords

Aerothermal heating
Catalytic efficiency
Hypersonic vehicle
Silica-based material
Surface catalytic
Thermal protection system

Cited by (0)

Li Kai is a Ph.D. student at the College of Aerospace Science and Engineering, National University of Defense Technology. He received his B.S. degree from the same university in 2013. His research areas include computational fluid dynamics and high temperature gas.

Liu Jun is a professor and Ph.D. supervisor at the College of Aerospace and Engineering, National University of Defense Technology. He received the doctor’s degree from the same university in 2004. His main research interests are high temperature gas aerodynamics, especially thermochemical non-equilibrium flow.

Liu Weiqiang is a professor and Ph.D. supervisor at the College of Aerospace Science and Engineering, National University of Defense Technology. He received the doctor’s degree from the same university in 1999. His main research interests are aerothermal analysis and structure design of thermal protection systems.

Peer review under responsibility of Editorial Committee of CJA.

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