Laminar flow occurs when a fluid flows in layers that are parallel. There is no disruption causing the layers to combine. When flowing at low velocities, these fluids don’t experience lateral mixing.
Static mixers operate by pumping two streams of fluid through the mixer. The mixer’s blade arrangement changes the flow in ways that mix the two streams. By combining multiple elements, the efficacy of this mixing process improves exponentially.
Two Laminar Flow Issues
Laminar flow offers two problems. You have a high momentum diffusion. This means that momentum easily spreads between different particles. This helps like particles stay together, and different layers of a laminar flow can even travel at different speeds against each other, like sliding a playing card quickly off a deck with one hand while moving the deck itself slowly with the other.
You also have to deal with low momentum convection. There’s little heat transfer between the layers. This helps each layer retain consistency and separation from the next.
Mixing Tanks are Expensive
Both of these characteristics make laminar flow mixing difficult. Combine this with the low speed of laminar flows and your options for effective mixing are limited. Many take the option of putting the laminar flow through mixing tanks with propellers or other moving mixing parts. These tanks are expensive, take up a large amount of space, and require a great deal of upkeep to maintain their moving parts. They also need to be cleaned often to remove build-up on their inner surfaces. This isn’t always the best, or most cost-efficient, option.
In-Line Static Mixers Reduce Costs
For laminar flow mixing, you need to create turbulence. This turbulence provides you with lateral mixing. Rather than relying upon mixing tanks to achieve this, a more elegant solution is that of in-line static mixers. As mentioned above, static mixers are places inside the pipes. They don’t have moving parts, but rather they influence the flow in ways that create lateral mixing. This is especially important for laminar flow mixing, where your options are limited.
Because they lack moving parts, there’s very little need for maintenance or replacement parts costs. Because they fit directly into the pipes through which your laminar flow travels, they also don’t take up any extra space. Multiple elements “stack” with each other, meaning that the influence of a second mixing element is exponential rather than additive.