Drop size is a by-product of atomization, and atomization is the process of generating drops. This begins by forcing liquid through a nozzle. The liquid’s stored energy along with the shape of the nozzle’s body and tip causes the liquid to emerge as small ligaments. These ligaments then break up further into very small “pieces”, which we refer to as drops, droplets or liquid particles. So, atomization is essentially the breakup of a liquid as it emerges from an orifice.
To get a better visual, picture a spray nozzle attached to a water hose. As you pull the nozzle’s trigger, water spurts out, usually as a dense spray at first that dissipates into droplets the farther it sprays from the nozzle tip. Kind of like the .gif to the side.
While this is, of course, hilarious, it also provides a great visual for how the spray exits the nozzle in a compact sheet, then spreads out and disperses into ligaments and eventually small droplets. If you were to look at these droplets more closely, each one would be a little different in its shape and size. This range of droplet sizes is referred to as the spray’s drop size distribution.
Now, our spray nozzles are far more sophisticated than the one you attach to a hose and each one is fine-tuned to create a very specific spray shape, pattern and drop size distribution. The shape of the nozzle’s orifice is precision engineered to create a certain spray pattern, either a hollow cone, full cone, flat spray or mist (among others). Each of these patterns will also produce a specific drop size distribution critical to the application for which it’s used.
To conclude, when our engineers refer to a spray’s drop size, we’re actually referencing its drop size distribution, or, the intended range of its droplet sizes.
Next in the series: Why Drop Size Distribution Matters for (Almost) Every Application