High Efficiency SiC/SiC Composite Heat Exchanger Structures

Scramjet propulsion systems for future hypersonic aerospace vehicles will be subjected to heating rates far greater than current materials can manage. In order to sustain high thermal loading while preheating the fuel, regeneratively cooled hot flow path components fabricated from ceramic matrix composites are being considered. The limited availability of high-temperature/environmentally durable materials focuses attention to silicon carbide fiber-reinforced silicon carbide (SiC/SiC) composites. These materials exhibit a unique combination of low density, high thermal conductivity and outstanding strength to near 3000oF. In order to exploit the benefits of SiC/SiC composites, methods are needed for fabricating high density/high conductivity components incorporating impermeable metal tube liners. Additionally, practical methods are needed for uniformly distributing coolant to the array of tubes via manifolding on the backside of the hot flow path surface. The objective of this Phase I program is to demonstrate a promising method for producing a high thermal efficiency SiC/SiC composite heat exchanger with low residual porosity and high interlaminar strength without having to resort to exotic and costly 3D fiber preforms. A functional actively cooled composite panel test article incorporating refractory metal tubes will be designed, fabricated and delivered to NASA for burner rig and/or thermal evaluation.