China Builds World’s First Boron Ramjet Engine To Launch Underwater Weapons At Supersonic Speeds

Scientists in China have constructed the revolutionary engine which they envisaged just 2 years ago. Initially meant for hypersonic weapons, it would be modified for use underwater to reach its targets at extremely high speeds and over a long distance.

It was in 2022 that researchers with the National University of Defence Technology (NUDT) in Changsha, Hunan province thought of employing this engine underwater. They added that cross-medium vehicles powered by such an engine could move at supersonic speed in air and in water to target aircraft carriers at speeds of over 200 knots.

The engine achieved 90% combustion efficiency in submarine mode during lab tests and its use could transform future warfare, said the research team. No country has the capability to counter such a weapon yet.

The engine is primarily fueled by boron, used in scramjet engines on a few Chinese hypersonic weapons. When boron comes in contact with oxygen, it burns intensely, accelerating the missile to over 5 times the speed of sound.

However, the biggest difficulty researchers faced was igniting it underwater.

For this, they modified the design by optimising the injection volume of water vapour in the combustion chamber and also the ratio of other ingredients in the fuel like aluminium and magnesium, which allows boron to burn more intensely in vapour.

During tests conducted in a lab, stimulating an underwater environment, they found that a yellow tail flame was seen near the outlet of the engine’s nozzle, per the project team headed by Professor Huang Liya, in a paper published in the Journal of Propulsion Technology.

The test showed that the engine worked smoothly and remained stable. The collected data showed that its exhaust jet velocity was over Mach 3, and its combustion efficiency was 87%.

Also, when the amount of boron was increased in the fuel, its specific impulse rose to 4712 newton-seconds per kg, one-third more than SpaceX’s latest Raptor rocket engine.

The team also said that boron has a wide range of applications for propulsion systems of cross-medium vehicles.

They concluded that the engine achieved stable operation and they will increase the content of boron in the fuel formula to enhance its performance further.

References: Lumi News, SCMP