Microgravity helps to seek out answers and models to refine the processes needed to efficiently burn solid fuel like iron dust. Are we witnessing the raise of a new “Iron Age”? Could we use metal powders rather than petrol to fuel our cars?
Solid fuels are used for burning a match, lighting a sparkler on New Year’s Eve also because the fuel inside the boosters of Ariane and of other rockets. But metals like iron also can burn, in powder form, and are entirely smokeless and carbon free.
Metals might be produced using clean energy, like from solar cells or wind turbines. That electricity is stored as chemical energy in metal powder at energy densities that are competitive with fossil fuels. This has the potential to reduce greenhouse gases emission globally, but a barrier to implementing this technology is the development of combustion systems which will efficiently burn the metal fuels, which needs a solid understanding of their combustion physics.
To understand the physics of metal fuel combustion, a cluster of iron powder must be suspended for about 30 seconds, the time needed to watch and study how a flame propagates. Researchers used sounding rockets and parabolic flights to run experiments in weightlessness and to validate existing models, yielding promising results.
The density of iron particles and therefore the composition of gases in combustion chamber are essential parameters, like in petrol car engine. Microgravity allows for the study of the laws of flame propagation, to optimize parameters in industrial burner designs, and reduce impact on the environment.
These space experiments also help us understand similar phenomena, like the spreading of contagious microbes and forest fires.
In a vote of confidence for the technique a student team at TU Eindhoven in Netherlands worked with industrial partners to design-a-metal combustion facility now installed at Swinkels Family Brewers, subsidized by the Dutch province of Noord-Brabant, used to produce steam for the brewing process.