Peculiar Fluid Dynamics Creates Hot and Cold Air

We’re fascinated by things with no moving parts or active components that work simply by virtue of the shape they contain — think waveguides and resonators for microwave radiation. A similarly mystical device from the pneumatics world is the Hilsch Vortex Tube, and [This Old Tony] decided to explore its mysteries by whipping up a DIY version in his shop.

Invented in the 1930s, vortex tubes are really just hollow tubes with an offset swirl chamber. Incoming compressed air accelerates in the swirl chamber and heads up the periphery of the long end of the tube, gaining energy until it hits a conical nozzle. Some of the outer vortex escapes as hot air, while the rest reflects off the nozzle and heads back down the pipe as a second vortex inside the outer one. The inner vortex loses energy and escapes from the short end as a blast of cold air – down to -50°C in some cases. [Tony]’s build doesn’t quite approach that performance, but he does manage to prove the principle while getting a few good-natured jabs into fellow vloggers [AvE] and [Abom79].

We’ve covered vortex tubes before, but as usual [Tony]’s build shines because he machines everything himself, and because he tries to understand what’s making it work. The FLIR images and the great video quality are a bonus, too.

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Brain controlled fluid simulation

Here’s another video demo of [Eric]’s Besmoke interactive fluid simulation that we covered earlier. It was put together for the BIL Conference last weekend. This time around he’s strapped the iPhone to his head (complying with California’s handsfree laws). To make things interesting, he’s also added OCZ’s Neural Impulse Actuator to provide brainwave input.

Besmoke – fluid dynamics

Besmoke is a fluid dynamics engine. It is compatible with any multitouch system, as well as the accelerometer in an iPhone. It also accepts audio input. The audio input can turn it into a fancy music visualizer that would even work with live or acoustic music. Different frequencies cause fluid to be injected from different “emitters”. There’s great info on his page, including the papers that he based this off of. We’ve covered [Eric]’s work before with his election party light system.