Design Concepts for CMC Leading Edges with Embedded Metallic Heat Pipes

This effort explores and assesses the options available for refractory composite leading edges cooled by embedded metallic heat pipes. Currently, the heat pipe cooled leading edges (HPCLE's) being investigated are fabricated primarily from refractory superalloys. However, even the best superalloys have a temperature limit of ~2400°F, which places substantial limitations on the possible geometry of a hypersonic vehicle's leading edge, and consequently, on its speed. With temperature capability of ~3000°F, refractory composites such as carbon/carbon (C/C) and carbon/silicon carbide (C/SiC) allow greater design flexibility and increased vehicle efficiency. The primary focus of this proposal is to analyze various forms of C/C and C/SiC that have not been previously considered as HPCLE materials. Using closed form solutions and finite element models, MR&D will investigate the thermal and structural performance of each material, and of different heat pipe cross section geometries to identify the best candidate designs. These candidate designs will also be optimized to have the lowest weight possible. Also under this effort, MR&D will design representative test articles of the candidate designs to be fabricated and tested in a Phase II effort.