ISSN Online: 2377-424X
International Heat Transfer Conference 3
HEAT TRANSFER IN STRUCTURAL HONEYCOMB COMPOSITES AT HIGH TEMPERATURES
Resumo
Experimental thermal conductance determinations on L-605 cobalt-base alloy panels of variable geometry were made to around 2000°F in high vacuum and air environments using an absolute thermal conductivity apparatus. Conductances in air environment were consistently higher than those in vacuum. Gaseous conduction and convection accounted for only a small fraction of the difference, the main effect being a large increase in the radiative contribution produced by increased emittance of the alloy through surface oxidation. Spectral emittance measurements provided data for quantitative assessment of this effect. The experimental results compared favorably with analytically predicted thermal conductances. The analytical values were based on a semi-empirical calculation procedure suggested by Swann which accounts explicitly for variations in panel geometry, panel temperature drop, and materials properties (emittance and metallic thermal conductivity).