Vorsana

A rotating disk in water will produce an array of spirals radiating from its center. These spirals are swirling flow, like tornados in the water, driven by disk momentum transfer. Water against the disk is advected, or transported in the fluid, radially outward in a boundary layer, but the boundary layer drags on the water above the disk. At the same time the water is advected around the disk axis of rotation, also dragging on the water above the disk. The outcome of all of these intersecting twists is swirling flow out from the disk axis of rotation, feed coming from the water above the disk. The curved vortex is a large scale coherent structure in turbulence.

Now imagine another disk opposite, rotating in the opposite direction, and you have von Karman swirling flow (s = -1). The large scale coherent structures now are like spokes in a wheel because the spiral bends from each disk cancel out. Boundary layers against each disk flow radially outward, and between the disks is a shear layer, where the coherent structures exist. But now there is no way to feed more water in between the disks to keep the flow going. So what you have is a closed system.

Most of us are accustomed to thinking of turbulence as chaos, i.e. total disorganization which is no benefit at all to anything. But here there is organized turbulence in coherent structures. The tornado and the hurricane are other examples of organized turbulence. Harnessing organized turbulence for fluid separation is what we do at Vorsana, Inc, going beyond closed systems to open systems.

The Navier-Stokes equations, which are the foundation of fluid dynamics theory, are relics from the steam age which are unreliable in three dimensions, i.e. in nearly all real-world applications. Nonlinear fluid dynamics is very unpredictable, as is attested by the impossibility of predicting the weather. The “butterfly effect” (a butterfly in Hong Kong causes a hurricane in Houston) is an often-cited illustration of nonlinear fluid dynamics, or chaos theory. There is even a $1 million prize offered by the Clay Mathematics Institute to anyone who can prove the existence and smoothness of Navier-Stokes in three dimensions. It is one of the seven great unsolved problems of mathematics. If we can’t predict the weather, how can there possibly be a totally predictive Theory of Everything in particle physics? So scientists, lacking a reliable mathematical tool for modeling turbulence in all but the simplest cases, have turned to brute force computer simulations to get a clue.

Much investigation has been done on the case of closed system von Karman swirling flow, particularly in liquid sodium magnetohydrodynamics studies. The closed system is typically a cylinder having counter-rotating end caps. The aspect ratio (ratio of disk separation to disk radius) of the setup is typically high in these studies, allowing for a large so-called recirculation flow from the cylinder wall (shrouding wall) back between the disks to the axis of rotation. Extremely high turbulence (Re ~ 10⁶) is produced near the shroud. Because closed systems have no mass flow in and out, they have little direct applicability to pollution control. However, the discovery of high turbulence at the periphery, where disk shear meets recirculation flow, suggests that there must be some way to improve scrubbing by improving mixing in a different way than the conventional methods of spraying or jetting the scrubbing solution into the flue gas. The proprietary McCutchen Scrubber does that, using an open system.

Open systems are flow-through setups. Mass flows in, and mass flows out, continuously. The McCutchen Scrubber uses von Karman swirling flow in an open system to effect good mixing for better scrubbing and to strip out the nitrogen ballast in flue gas. So carbon dioxide is captured and scrubbed at the same time, in very high turbulence and with long residence time in the processing zone, in a process driven by mechanical means. Radial counterflow between the disks continuously takes flue gas in at the axis, expels nitrogen and water vapor out at the axis, and collects carbon dioxide, fly ash, mercury, NOx and SOx at the periphery. The radial vortices of von Karman swirling flow act as sink flow conduits for light fractions, such as the nitrogen in flue gas.

At Vorsana, Inc. we have also developed proprietary technology for applying open system von Karman swirling flow to other important fluid separation tasks, such as extracting fresh water from reverse osmosis reject brine or seawater, separating out hydrogen sulfide, water vapor, mercaptans, and other junk from the methane in natural gas, and stripping volatiles and dissolved non-condensible gases in municipal or industrial wastewater.

Organized turbulence is our hope for a solution to the global climate change crisis. If a forcing regime is put in place, driven by cheap mechanical energy, the fluid fractions will naturally separate themselves, spontaneously. The forcing regime then collects the effects and keeps the process going continuously.

The difference between this and the old-fashioned approach of micromanaged chemically-based systems for pollution control can be compared to the difference between top-down total control tyranny, often proved to be a failure in human government for generating prosperity, and the concept of freedom under strict and wise law, which allows the people to generate prosperity spontaneously and provides a coherent structure for collecting the tiny individual contributions.