In an effort to meet future demand for hypersonic flight, Chinese scientists have created the world’s first detonation engine that runs on regular jet fuel. Wind tunnel tests of the prototype have confirmed the engine’s potential to propel aircraft to speeds of up to 20,000 km/h, or Mach 16.
Image source: AI generation Grok 3/3DNews
The rotary detonation engine (RDE) developed in China was upgraded to an oblique detonation engine (ODEW) design. About four years ago, a similar engine was created in the United States, at the University of Central Florida. The American development demonstrated the potential of the approach, ensuring continuous operation of the engine in an aerodynamic chamber for 3 seconds. The fuel was a mixture of hydrogen and oxygen.
Chinese scientists have taken a step forward by demonstrating that the ODEW engine can run on ordinary kerosene. It is safer, simpler and more reliable, which could be a breakthrough in hypersonic propulsion and expand the possibilities of air and space travel.
In a series of experiments at the JF-12 wind tunnel in Beijing, known as the Hyperdragon, which simulates high-speed flight conditions at altitudes above 40 km, researchers from the Chinese Academy of Sciences (CAS) achieved stable oblique detonation wave regimes using RP-3 jet fuel – common commercial kerosene.
The results, published in the Chinese Journal of Experiments in Fluid Mechanics, show that the combustion rate of the ODEW prototype was 1,000 times faster than that of traditional jet engines. The engine operated reliably at speeds ranging from Mach 6 to Mach 16, where conventional jet engines struggle to operate.
Due to wind tunnel limitations, the Chinese ODEW engine only sustained continuous operation for 50 ms, equivalent to about 150 meters of flight at Mach 9. However, this was enough time for the researchers to get a full picture of the engine ignition process and the self-sustaining shock wave. A special feature of the design was the 5 mm protrusions on the inside of the detonation chamber, which created an amplifying effect – they served as a kind of points for self-sustaining detonation of the fuel.
ODEW engine combustion chamber prototype. Image source: Chinese Academy of Sciences
According to the developers, the combustion chamber of the new engine is 85% shorter than that of a ramjet engine, which allows for a significant reduction in the weight of the aircraft and an increase in the flight range. For decades, hypersonic engines have been powered by hydrogen or ethylene, and although this fuel ignites quickly, it requires special storage conditions. On the other hand, RP-3 kerosene, while having a higher energy density and ease of logistics, has long ignition delays, which makes it difficult to start the engine in flight. The developers got around this limitation by injecting a pre-compressed and heated fuel-air mixture into the combustion chamber.
The project is part of China’s ambitious plan to create a plane by 2030 that can fly anywhere in the world in an hour. For example, from Shanghai to Los Angeles in just half an hour. This technology could also allow reusable space planes to fly in the atmosphere and in orbit. At Mach 16, a relatively small rocket booster would be needed to propel the space plane into orbit on its own. There are still many technological challenges, but scientists promise to begin testing prototypes in flight by the end of this year.