BLAST-NOZZLE

In the project BLAST-NOZZLE, the Fraunhofer Heinrich Hertz Institute, HHI together with the Fraunhofer ILT (Fraunhofer Institute for Laser Technology, Aachen) is investigating the transfer of femtosecond laser structuring of metal surfaces to increase the thermal emissivity on laval nozzles of rocket engines made of copper alloys.

As part of the Fraunhofer Cluster of Excellence for Advanced Photon Sources CAPS and within the BLAST-LARGE project, such surface treatments were developed for large objects such as the outer walls satellites made from aluminum. Such surface structures make it possible to optimize radiative heat dissipation (heat radiation) for efficient cooling in space. The BLAST-NOZZLE project aims to exploit the excellent stability of surface structuring with regard to external influences such as high temperatures and radiation in order to withstand the extreme temperatures of a rocket nozzle up to just below the melting point of the metal alloys used. For this purpose, the process of laser processing of flat surfaces is transferred to the conical geometry of a Laval nozzle. Demonstrators of the lava nozzles are fired with methane/oxygen in the HHI's high temperature test chambers and the stability as well as emissivity of the surface structure are evaluated.