Images of from a high-speed camera reveal a microbead formation process during the vapor explosion of liquid metal dropping into a pool of water.
The explosive reaction of a liquid metal dropping into water has been captured with high-speed cameras by researchers from King Abdullah University of Science and Technology (KAUST), Saudi Arabia. The images reveal how the explosive formation of water vapor around the liquid metal influences the shape of the metal as it hardens . For certain metals, perfectly-shaped microbeads are created during the powerful reaction with water.
Immersion of hot liquids in other liquids is not uncommon, even outside of the laboratory. An example is hot lava from a volcanic eruption encountering water reservoirs or flowing into the sea. This interaction can lead to dramatic reactions when vapor layer forms around the liquid metal. The vapor layer can become unstable and quickly expands into hot clouds of water and ash, noted Siggi Thoroddsen from the KAUST High-Speed Fluids Imaging Laboratory, who also led the research team.
“This happened when the Icelandic volcano Eyjafjallajökull erupted in 2010 and grounded airplanes all over Europe," he said.
The researchers studied related reactions in the lab using a metal alloy known as Field’s metal, which melts at low temperatures of around 60 degrees Celsius. With experiments conducted at 550 degrees Celsius metal temperature, the transfer of energy between the metal and the water is very violent. KAUST Ph.D. student Nadia Kouraytem wore a full protective facial mask and a fire-resistant lab coat during these experiments. High-speed cameras captured the explosive process at speeds of up to 50,000 frames per second.
The images obtained were dramatic and showed an explosive reaction that tore the metal apart. In the case of Field’s metal, small spherical microbeads formed during the process.
During the reaction, the metal transitioned through several stages with increasing ferocity. While initially only a small part of the metal interacted with the water, over a longer period increasingly more of the metal was exposed and took part in the reaction until the disintegration of the liquid metal into small beads.
The unusual microbead formation occurs due to the low melting temperature. Metals with a higher melting temperature (such as tin) solidify faster because their higher solidification temperature is reached more quickly upon cooling so that there is less time for the material to disintegrate. An example is the porous structures seen in solidified lava from volcanic eruptions.
In the case of Field’s metal, the beads are highly uniform, and it will be interesting to study their creation processes further, noted Thoroddsen.
“In future experiments, we want to better control the original drop, change its size and impact velocity. This should further probe the instabilities of the vapor layer that forms around the metal,” he said.
 Kouraytem, N., Li, E. Q. & Thoroddsen, S.T. Formation of microbeads during vapor explosions of Field’s metal in water. Physical Review E 93, 063108 (2016).
Michelle D'Antoni | Research SEA
Glass's off-kilter harmonies
18.01.2017 | University of Texas at Austin, Texas Advanced Computing Center
Explaining how 2-D materials break at the atomic level
18.01.2017 | Institute for Basic Science
An important step towards a completely new experimental access to quantum physics has been made at University of Konstanz. The team of scientists headed by...
Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...
Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.
While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...
Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales
Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...
Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.
As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...
19.01.2017 | Event News
10.01.2017 | Event News
09.01.2017 | Event News
19.01.2017 | Earth Sciences
19.01.2017 | Life Sciences
19.01.2017 | Physics and Astronomy