The promise of metal fuels
We use solid fuels every day: they are used for burning matches, lighting sparklers, and even inside the boosters of rockets, such as the ESA's Ariane. However, metals such as iron can also be used as fuel in powder form, and they are completely smokeless and carbon-free.
As ESA points out in its statement, "metals could be produced using clean energy, such as from solar cells or wind turbines. That electricity is stored as chemical energy in the metal powder at energy densities that are competitive with fossil fuels."
"This has the potential to reduce greenhouse gasses emission globally, but a barrier to implementing this technology is the development of combustion systems that can efficiently burn the metal fuels, which requires a solid understanding of their combustion physics," the statement continues.
Experiments in microgravity
In order to better understand the physics of metal-fuel combustion, the ESA researchers used microgravity conditions to suspend a cluster of iron powder for approximately 30 seconds; the time needed to study how a flame propagates.
The team used sounding rockets and parabolic flights to run experiments in weightlessness. In doing so they were able to validate existing models, bringing us one step closer to metal fuels back down on Earth.
They continue to study the density of iron particles and the composition of gases in the combustion chamber. Once they collect enough data, the researchers believe that metal fuels might be usable in cars internal combustion engine cars and vehicles; this would be an enormous step towards making old vehicles clean.
Source: European Space Agency