Generating droplets of different sizes with a single nozzle
Generating droplets of different sizes with a single nozzle lead image
Droplets are an important component of research into nature, the atmosphere, agriculture, and biopharmaceuticals. Creating droplets of a specific size and investigating their fundamental behavior and interactions with other objects is crucial for 3D printing, liquid dispensing in biological and chemical applications, and collisions with surfaces in aircraft icing studies.
However, the performance of many droplet generating systems depends on the level of liquid in the storage chamber. Inconveniently, to change droplet size, the devices must also change their internal nozzles.
Wang et al. demonstrated a device that avoids both of these problems, creating droplets of different sizes conveniently, efficiently, and reliably with the same nozzle. The design is based on a 2-way high-speed solenoid valve, with a pulse voltage to drive the valve open and then immediately closed.
“During the opening and closing process, the fluid flows into the nozzle under the action of pressure to form a liquid jet, which is then broken and ejected from the nozzle to generate droplets,” said author Liping Wang.
To accurately generate the droplets, the driving signal and pressure must be carefully coordinated. By adjusting these two parameters, the team created droplets from 0.7 to 2.2 mm in diameter.
“Under the combination of short pulse signal and high pressure, the droplet size can be smaller than the nozzle size, which is difficult to achieve in many droplet generation systems,” said Wang.
The technology could be used for a wide range of applications that require precise control of droplet size. The team aims to continue studying the formation mechanisms of droplets in the future.
Source: “Experimental investigation on the performances of a valve-based and on-demand droplet generator producing droplet in a wide size range,” by Liping Wang, Weiliang Kong, Peixiang Bian, Fuxin Wang, and Hong Liu, AIP Advances (2022). The article can be accessed at https://doi.org/10.1063/5.0107610 .
