China’s magnesium-powered scramjet breakthrough nearly doubles thrust at Mach 6
The team found that the use of magnesium was able to nearly double scramjet thrust at high speed and altitude.
Chinese researchers have reportedly developed a new type of afterburner for scramjet engines that could achieve Mach 6 at altitudes of 98,425 feet (30 km). According to the team behind it, this was achieved by cleverly incorporating magnesium powder into the hot exhaust gases produced by burning conventional jet fuel.
Magnesium was chosen because it is a highly reactive metal that ignites explosively without needing atmospheric oxygen. This is important for engines like scramjets, which tend to burn kerosene in the presence of oxygen from the atmosphere to generate huge amounts of thrust.
Since they are also designed to operate at very high speeds (typically hypersonic), conventional kerosene combustion reaches a limit, producing exhaust gases mainly consisting of carbon dioxide (CO₂) and water vapor (H₂O).
Under these conditions, magnesium can take advantage of these “waste gases” and burn vigorously when injected, creating extra thrust using energy that would otherwise be wasted.
Using magnesium to boost scramjets
The new afterburner injects the magnesium powder downstream into these hot gases (around 2780.6°F, or 1527°C). This results in secondary combustion, where the magnesium reacts with the water vapor and CO₂ to produce more heat and thrust.