Chinese scientists say they have developed new type of rocket engine driven by explosive shock waves
- The continuous rotating detonation engine promises to be more efficient than conventional rocket engines and could help power hypersonic plans
- The technology was first proposed in the 1950s and a team from Tsinghua University is hopeful they have found a way to reduce the engine’s weight
A research team in Beijing says they have built a new type of rocket engine powered by explosions.
The continuous rotating detonation combustion engine, developed by Professor Wang Bing and colleagues from the school of aerospace engineering in Tsinghua University in Beijing, is driven by explosive shock waves spinning like a tornado faster than the speed of sound.
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The idea of an engine powered by explosion was proposed by Soviet scientists as early as the 1950s to launch rockets into orbit.
This type of engine would be more efficient than a normal rocket engine and many prototypes have been built over the years, but most had a cylindrical combustion chamber that made the engine too heavy for real-life applications.
Wang’s team said that they had got around the problem by reducing the cylinder to a disk.
The new layout was previously considered too difficult to build because it required a complete redesign of nearly all components, but tests have proved the technology worked, Wang and his colleagues wrote in a conference paper published on cnki.net, China’s largest online research platform last month.
Fuel burns much more efficiently when detonated, and an explosion-powered rocket could lose 50 per cent fuel compared with normal rocket engines, according to Wang’s team.
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But the detonations risk damaging components and need to be controlled.
In a traditional detonation engine with the cylinder design, fuel and air was injected into a space between two round walls and ignited.
Explosive shock waves spin the walls around and trigger more explosions.
The cylinder walls allowed the shock waves to develop.
But starting and maintaining the unstable process in the disk was much more challenging due to the limited space, said the researchers.
Their experiment suggested that the key components must follow some extremely strict design requirements. For example, a tiny change in the location and direction of a fuel injector means the engine will not start.
Putting many different components into the tight space was another challenge. The researchers said that they did not even have room for bolts to join some critical parts and instead, they stuck the components together by friction.
In January, Wang’s team conducted the first test flight of their air-breathing continuous rotation detonation engine.
The engine, mounted on top of a two-stage rocket, used a cylinder design, according to photos released by Tsinghua University.
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The engine ignited at high altitude and provided additional thrust for the second stage rocket.
In a paper published in 2020, the team said that they planned to combine the denotation technology with a scramjet to power a space plane that can arrive in near-earth orbit at hypersonic speed.
The scramjet, an air-breathing engine that only works at extremely high speeds, would use the high-speed exhaust from the detonation rocket engine to get started earlier and work more efficiently.
It remains unclear how much thrust the disk-shape engine can generate and when it would go for a flight test. The team could not be reached for comment.
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Other countries, including Russia, the United States, France, Poland and Japan, have developed numerous detonation engines in recent years but most of their tests were conducted on the ground.
In August last year, Japan’s national aerospace agency Jaxa tested a non-breathing detonation engine mounted on a sounding rocket in space.
