Detonation represents a supersonic combustion wave characterized by a shock wave driven by the energy released from closely coupled chemical reactions. This dynamic form of pressure gain combustion efficiently transforms chemical energy into thrust, making it highly valuable in aerospace applications.
For decades, researchers have sought to exploit detonation to enhance thermodynamic cycle efficiency and elevate the performance of propulsion systems.
Since the 1950s, several detonation engine designs have emerged, including pulse detonation engines, oblique detonation engines, and rotating detonation engines.
However, these designs face significant challenges, such as poor thrust continuity, high starting Mach numbers, and insufficient performance gains, which limit the widespread application of detonation propulsion technology.
Recently, an innovative solution has been presented by Dr. Haocheng Wen and Prof. Bing Wang from Tsinghua University. They proposed a new concept for detonative propulsion, called the Ram-Rotor Detonation Engine (RRDE), which is expected to overcome the limitations faced by existing detonation engines, promising to revolutionize the future of detonation propulsion.
“The original intention of developing this new engine is to improve the structures of rotating detonation engines,” said Dr. Haocheng Wen, “this concept is also inspired by the ram-rotor compressor.”
The ram-rotor detonation engine (RRDE) stands out as an innovative propulsion technology, integrating a rotating rotor with helical symmetric blades and a stationary casing. This advanced engine design allows a combustible mixture to undergo critical stages: compression, detonation combustion, and expansion through variable cross-sectional channels between the blades, resulting in highly efficient thrust generation.
Recent investigations included both theoretical and numerical analyses of the RRDE. Researchers developed a theoretical model to understand how propulsion performance is influenced by factors like inlet velocity, rotor rim velocity, and equivalence ratio. Notably, for a stoichiometric hydrogen/air mixture, the RRDE can achieve a total pressure gain exceeding 3.
Additionally, they performed numerical simulations based on the typical structure of the RRDE, which provided insights into the engine’s characteristic flow field and propulsion capabilities. The simulation outcomes reveal that the detonation wave can be stabilized and remain fixed within the blades due to the specific configuration and can adjust to changes in parameters like the equivalence ratio within certain limits.
“Our study primarily verifies the performance benefits and operation feasibility of the RRDE,” said Dr. Haocheng Wen.
The authors highlight that the RRDE offers several advantages, such as its simple and compact structure, high efficiency, and adaptability to various flight Mach numbers.
However, they also openly recognize that there are many challenges associated with the implementation of the RRDE that need to be addressed, including the stabilization of the detonation wave, issues with supersonic boundary layer interference, the use of high-speed rotors, and thermal protection, among others.
“Our team is conducting ongoing research on key scientific and engineering issues in RRDE,” said Prof. Bing Wang.
They are optimistic that the RRDE could provide high-performance propulsion for supersonic vehicles in the future.
Journal reference:
- Haocheng WEN, Bing WANG. Primary investigation on Ram-Rotor Detonation Engine. Chinese Journal of Aeronautics, 2024; DOI: 10.1016/j.cja.2024.05.016
