A new study of the discovery was published in the journal Physical review fluids.
Phase changes in water are well understood by most people; heating ice (solid) makes water (liquid), and heating water produces water vapor (gas). Enter the Leidenfrost effect, first described in a 1751 publication, which refers to a phenomenon in which a drop of water placed on an aluminum plate heated to at least 150 degrees Celsius (302 degrees Fahrenheit) will not boil.
As the droplet approaches the plate, water vapor will form between it and the plate, dampening the liquid and preventing it from coming into direct contact with the plate so that it can slide around the surface in the same way as an air hockey puck. Associate Professor Jonathan Boreyko and candidate Mojtaba Edalatpour tried to investigate whether ice cream would have a similar effect.
“There are so many papers out there about floating liquid, we would ask the question about floating ice. It started as a curiosity project. What drove our research was the question of whether it was possible to have a three-phase Leidenfrost. Effect with solid, liquid and steam, “said Boreyko.
They found that to recreate the Leidenfrost effect with ice, the temperature of the aluminum plate had to be at least 550 degrees Celsius (1022 degrees Fahrenheit). Before that temperature, the ice rested on the liquid meltwater layer and kept the bottom in contact with the aluminum plate, causing it to boil at 100 ° C (212 ° F) while maintaining a temperature of 0 ° C (32 ° F). side in contact with the ice. Significantly more energy was required to create the levitation after ove (which brings the temperature difference in this layer.
“The temperature difference that the ice uniquely creates across the water layer has changed what happens in the water itself, because now most of the heat from the heating plate has to cross the water to maintain the extreme difference. So only a small fraction of the energy can be used to produce steam longer, “Boreyko said.
“It’s much harder to float the ice than it was to float the water drop. The heat transfer plunges as soon as the levitation begins, because when the liquid floats, it no longer boils. It floats above the surface instead of touching and touching it, “that makes it boil the heat away. So for heat transfer, levitation is terrible. Boiling is incredible,” Boreyko continued.
You can read more from the survey here.