Making a splash on cryogenic surfaces

On a rainy day, a classic physical property is on display: droplet splashing. How liquids splash is not just important for keeping one’s clothes dry, but for applications from inkjet printing to spraying crops to rapidly cooling surfaces, where the high impact velocity of a splash can introduce inefficiency and fluid loss.

Zhenyue Yuan and Xiong Wang designed an experiment to investigate how droplets splash on cryogenic surfaces, an important substrate for low-temperature manufacturing and space exploration. They found that while hyper-cold surfaces did not change how droplets splashed, in general, smaller droplet sizes produced smaller splashes.

“Droplet splashing is a fundamental phenomenon in our life and also in industry,” said Wang. “It is widely studied by researchers at room temperatures and high temperatures, but in cryogenic conditions, it receives limited attention.”

The researchers designed a cryogenic apparatus that used liquid nitrogen to keep its surface near -195 °C. Then, an attached syringe needle dispensed uniform droplets of ethanol, deionized water, or aqueous propylene glycol solution onto the surface while an imaging system captured the splash at 10,000 frames per second. Finally, the team used their experimental data to develop a model predicting the impact velocity of different droplets in cryogenic conditions.

They found that a liquid’s viscosity, surface tension, and density dominated its splash behavior as seen at warmer temperatures, since freezing takes orders of magnitude more time than a splash. They also determined that smaller droplets generate smaller splashes, and larger droplets require lower impact velocities to splash less.

The team hopes their results can help engineers design more efficient systems that lose less mass to splashes.

Source: “Droplet splashing dynamics on cryogenic surfaces,” by Zhenyue Yuan and Xiong Wang, Physics of Fluids (2025). The article can be accessed at https://doi.org/10.1063/5.0303826 .