Radiation heat transfer during hypersonic flight: A review of emissivity measurement and enhancement approaches of ultra?high temperature ceramics

Emissivity as a function of wavelength, direction, and temperature correlates to material's efficiency in radiating thermal energy. Knowledge emissivity is essential for designing developing radiation-cooled protective systems hypersonic applications. It desirable achieve high (with value close 1) maximize heat radiation from hot surface vehicle's leading edge during atmospheric re-entry. With the goal providing materials community with this necessary knowledge, article offers basic understanding radiation, methods measuring at temperatures, comprehensive overview ultra-high ceramics.