Views: 503 Author: Site Editor Publish Time: 2017-05-19 Origin: Site
As interest in nano-technology and the ever-increasing demand, Nano-printing and coating demand will also increase, which need to be deposited on the surface of tiny drops of liquid. Now, researchers from Tsinghua University in Beijing, has developed a new theory describing surface Nano-droplets on impact deformation and rupture.
The findings are published in the publication "physical fluid", you can help researchers improve the quality of printing and coating of nano. For example, spray coating, drop impact surface is smaller and faster, the better the quality of the coating, Department of engineering mechanics of Tsinghua University Professor Chen Min (phonetic) said. However, in some impact speed, the droplets will burst and spatter, damage the coating.
Therefore, in order to improve print and spray technology, we need to better understand cause droplets on impact deformation of surface conditions, and how they can rupture. However, because the Nano-liquid drop experiments are very difficult, researchers need to rely on computer simulations.
Chen and his team used a technique called molecular dynamics simulation, in which they simulate each of the molecules constituting a drop of. About 12,000 units of each droplet of about 8.6 nm in diameter, and to strike the surface of hundreds of meters per second.
Collection occurs when a computer simulated water molecules hit the flat surface. "We have developed a model to describe the deformation process, the other describing the decomposition process," Chen said.
"The model improved the team's previous work, but split model is brand new. "Split model combining theory and simulation results, provide a formula, researchers can use this formula to calculate the drop when broken. According to Chen, in the application of the model is ready to use.
But there is a limitation is that the model is validated only for nano-droplets rather than work for larger droplets.
"Due to decomposition of droplet in micro and nano-scale is different," study co-author Li Buxuan (phonetic) said. This model also applies to the so-called Newtonian fluid, such as water. Researchers are trying to develop the model of non-Newtonian fluids, such as oil or corn starch and water (sometimes called Oobleck) viscous mixture.
For example, for 3D printing polymer and biological materials (such as human tissue and organs) will require non-Newtonian model. The model applies describes how water droplets collide with aircraft and ice, it is a security risk. These droplets suspended in clouds is usually in the range of 20 to 50 microns, is greater than the simulation of water droplets. However, Chen said, their model is useful, because not many people know how these droplets hit the aircraft.
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