QAMD additively fabricates first bimetallic RDRE injector

Quadrus Corporation’s Advanced Manufacturing Division (QAMD) has fabricated the world’s first bimetallic rotating detonation rocket engine (RDRE) injector via Selective Laser Melting (SLM). This breakthrough marks a groundbreaking achievement in the realm of additive aerospace propulsion technology and represents a culmination of a series of Small Business Innovation Research (SBIR) Phase II and Phase III efforts managed by engineers at NASA MSFC.

Recently validated by NASA researchers for adoption in space – and actively developed by the Air Force Research Laboratory (see video below) – a rotating detonation engine (RDE) uses a form of pressure gain combustion, where one or more detonations continuously travel around an annular channel. Computational simulations and experimental results have shown that the RDE has potential in transport and other applications. In detonative combustion, the flame front expands at supersonic speed. It is theoretically more efficient than conventional deflagrative combustion by as much as 25%. Such an efficiency gain would provide major fuel savings, while current disadvantages include instability and noise.

RDRE injectors face significant challenges due to the intense heat generated by the spinning detonation waves. In response, QAMD manufactured a solution featuring a thin faceplate made from thermally conductive GRCop-42 and a manifold made of oxidation-resistant nickel-based superalloy Monel K500. GRCop-42 allows propellants to effectively cool the injector face while the oxidation resistance and strength of Monel K500 allows thinner walls in the manifold, resulting in a lighter design solution tailored to the demands of RDRE applications.

Quadrus Corporation’s advanced manufacturing process overcomes numerous hurdles associated with bimetallic SLM fabrication, including precise geometrical alignment, mitigation of the risk of material cross-contamination, and the formation of high-strength bimetallic bonding. QAMD demonstrated strict attention to detail in all three areas while maintaining an orifice hole of 0.040 in. through the bimetallic region. This achievement underscores Quadrus Corporation’s commitment to pushing the boundaries of additive manufacturing technology.

The bimetallic injector brings to a head a multi-year NASA SBIR effort focused on thermal management for combustion injector applications. The success includes the development of Quad Mesh, a groundbreaking approach to transpiration cooling for injector faceplate applications. Quad Mesh enables customizable permeability in high heat flux regions, synergistically complementing the SLM build process and depowdering techniques.

The bimetallic injector, along with a monolithic GRCop-42 injector that includes the Quad Mesh technology, is slated for hot fire testing at NASA’s Marshall Space Flight Center during the summer of 2024, marking a significant step forward in advancing thermal management for rocket injector applications. Quadrus Corporation continues to drive innovation in the aerospace industry, exemplifying a commitment to excellence and pushing the boundaries of what is possible in space propulsion technology.