Refractory-composite/heat-pipe-cooled leading edge and method for

Abstract

A thermal protection system containing several innovative features has been developed with heat pipes embedded in a composite material. The techniques used in the fabrication of the heat pipes permit a smaller radius and a higher use temperature heat pipe than could be manufactured under pervious techniques. The techniques used to embed the heat pipes in a refractory composite material yield a light weight leading edge that is able to tolerate the thermal stresses generated by the difference in thermal expansion between the heat pipes and the composite material. The heat pipes for the leading edge have a 'J-shape', and are placed so that the long leg of the heat pipe alternates between the upper and lower surfaces. A coating is placed on the heat pipes that protects the heat pipe from oxidation and reaction with the components of the composite material. A compliant layer is placed between the heat pipes and the composite material to reduce the effects of the thermal stresses that arise due to the mismatch of thermal expansion between the heat pipe and the composite material. A gap forming layer may also be placed between the heat pipe and the composite material so that after it is removed or shrunk, a small gap will be left that will reduce thermal stresses.