Aconity3D and LEAP 71: Noyron AKL-5 aerospike rocket engine showcase at Formnext 2024
This part is exhibited at Formnext 2024 in Frankfurt, Germany, at the Aconity3D booth Hall 12.0 D02
LEAP 71 colaborated with Aconity3D to produce this 5kN aerospike rocket engine printed from CuCrZr, a high-performance copper alloy. The engine uses cryogenic liquid oxygen and kerosene as propellants.
Aerospikes are highly efficient rocket engines that forego the bell-nozzle of traditional thrusters and instead use a toroidal combustion chamber around a central spike. Because the spike sits in the middle of the engine exhaust, which reaches temperatures of 3500ºC, it needs to be actively cooled, in this case with cryogenic liquid oxygen. The outside chamber wall is regeneratively cooled using the kerosene fuel.
The aerospike design was created autonomously by the Noyron RP Large Computational Engineering Model. It was 3D-printed on an Aconity Midi+ Metal Powder Bed Fusion (MPBF) printer.
The thruster’s 5kN (1100lbf) thrust level is suitable for an orbital kick stage. The design integrates all thruster components, including combustion chamber, spike, and injector head in one functionally integrated part.
An aerospike has the same efficiency from sea level atmospheric pressure to the vacuum of space, which makes it ideally suitable for applications where the operating conditions vary, such as for propulsive landing or single stage to orbit. Traditional engines require heavy and bulky vacuum bell nozzles that incur a massive weight penalty on the upper stage of a rocket, which the aerospike engine avoids.
One challenge for the manufacturing of the object are the very shallow unsupported overhang angles at the throat of the engine, which are dictated by the physics of the aerospike design. As the regenerative cooling channels also have to route along the same geometry, the surface quality, especially on the downskins, is hard to get right, especially with a demanding material like copper.
Aconity3D optimized the scan strategy and print parameters, until the quality exceeded expectations. The 210mm high thruster was printed with an adaptive layer height between 60μm and 90μm in less than 62 hours using 6.9kg of copper alloy.
The central spike is cooled with liquid oxygen, which is highly reactive with copper. Even small amounts of powder left in the channels could combust and cause the engine to fail. Since the part is printed in one piece, depowdering is very challenging and post-inspection difficult. After initial processing at Aconity3D it was sent to Solukon for professional powder removal, using their Pathfinder process.
Finally, the engine was heat treated at the Fraunhofer Institute for Laser Technology.
The combination of Computational Engineering and advanced industrial 3D printing allows us to functionally integrate the engine components, including combustion chamber, cooling features, manifolds, injector, ignition system, and structural elements.
The aerospike engine is printed from just one part, so no sealing or assembly is required, and post-machining is minimal (thread cutting).
The engine is ready to run, after attaching the propellant feeds and instrumentation sensors.
LEAP 71 plans to conduct a hot fire testing campaign of the manufactured aerospike in the coming weeks.
As the engine was generated by the Noyron Large Computational Engineering Model, larger or smaller engines can be generated to fit specific customer profiles.
About Aconity3D
Aconity3D’s primary business focuses on developing advanced equipment for powder bed laser melting and direct energy deposition of metals. The company aims to combine maximum functionality with modular, open-ended machine concepts, all at competitive pricing tailored to specific customer requirements.
Currently, Aconity3D offers six fully-configurable machine models, catering to a broad spectrum of applications. This hardware portfolio is supported by hands-on training sessions, workshops, feasibility studies, and metal part production services for clients, creating a comprehensive solution for powder bed laser melting. As a result, this technology becomes accessible to a wider range of businesses, including small and medium-sized enterprises.
For more information, visit https://www.aconity3d.com
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