Regeneratively Cooled Ceramic Matrix Composite Nozzle Assembly for Reduced Weight

All rocket missions benefit from having lower structural mass and higher specific impulse, both of which contribute to larger payload fractions and therefore lower mission cost. High temperature materials such as ceramic matrix composites (CMCs) are an avenue to lower engine mass because of the low density and high specific strength of the material. They also have a high maximum temperature and so contribute to high specific impulse by reducing the thermal load that must be removed from the nozzle structure, keeping the heat in the exhaust stream where it belongs. However, even the maximum temperature of CMCs is not high enough for stoichiometric methane-oxygen or hydrogen-oxygen flame conditions. In this Phase I effort, PSI will develop a regenerative cooling architecture and manufacturing method for a combined CMC/metal structure. The major difficulties encountered so far in adding fuel cooling to CMC nozzles is that CMCs are typically permeable and have low thermal conductivity. PSI will address these challenges using cold-spray metallization and metal additive manufacturing to build metal cooling passages on a corrugated CMC nozzle. If the proposed project is successful, it will result in a CMC/metal structure capable of withstanding combustion chamber, throat, and nozzle conditions by using regenerative cooling. The Phase I program will end with validated thermal design and manufacturing methods for a full regenerative CMC nozzle. This technology is applicable to a range of nozzle sizes from the 1.2 klbf MSFC “workhorse” nozzle configuration which would be targeted in a Phase II project, through booster-scale nozzles. At the end of the Phase I project, a manufacturing prototype of the CMC/metal cooling structure and design and test data will be provided to NASA. More »