The Technical University of Dresden (TUD), the Ariane Group, and the German Aerospace Center (DLR) have tested a new combustion chamber technology in the research project "Numerical and Experimental Demonstration Study for Engines using Rotating Detonation" (NEDSERD). A so-called Rotating Detonation Rocket Engine (RDRE) was tested.
According to the participants, it is the first water-cooled combustion chamber of its kind in Germany and at the same time the first actively cooled hydrogen-oxygen RDRE in Europe. The tests took place at the DLR's space propulsion facility in Lampoldshausen in Baden-Württemberg.
Rotating detonation rocket engines fundamentally differ from conventional rocket engines. In traditional engines, the fuel burns continuously at constant pressure. In contrast, RDREs use a rotating detonation wave in the combustion chamber, which converts the fuel explosively. According to the scientists involved, this technology could use fuels more efficiently. Additionally, the shorter combustion region offers the potential to build engines that are lighter and more compact. For space travel, this could mean lower fuel consumption, higher payload capacities, and reduced launch costs.
Water cooling enables longer test runs
Previous European rotating detonation rocket engines were mostly operated uncooled and ran for only a few seconds. This made it difficult to precisely capture the heat flows in stationary operation. Therefore, TU Dresden developed a water-cooled variant that works with the fuel combination of hydrogen and oxygen. The component was additively manufactured using Laser Powder Bed Fusion (LPBF), also known as metal 3D printing.
The project included two test campaigns. In the first, an uncooled RDRE from DLR was used. The second campaign focused on the larger, water-cooled combustion chamber from TU Dresden. The focus was on temperature measurements to capture the thermal loads on the structure.
Nine test runs over a total of 80 seconds
“The central challenge, besides developing the cooled combustion chamber itself, was to analyze the high thermal loads under various operating conditions,” explains Christian Bach, head of the research field of space transportation systems at TU Dresden. As an excellence university, it is one of the most powerful research institutions in Germany. “For this, we used three different methods for temperature and heat flow measurement. In total, we tested the water-cooled combustion chamber in nine test runs with a total duration of about 80 seconds, with individual combustion phases lasting up to ten seconds.”
According to Bach, the results show that water cooling via a cooling jacket enables longer operation and at the same time provides extensive data from stationary operation. “For the hydrogen-oxygen fuel combination, these data, as far as known from publicly available sources, had not been collected before,” says Bach.
Foundation for future engine development
The tests are intended to form the basis for a detailed investigation of the operating behavior of rotating detonation rocket engines and to gradually make the technology usable for rocket applications. From the perspective of the project consortium, RDREs could make space travel more economical through higher efficiency and lighter construction.
The NEDSERD project is supported by the Federal Ministry for Economic Affairs and Energy.
