Vortex tube

The vortex tube, also known as Ranque - Hilsch vortex tube is a device with no moving parts, the gas can be in a hot and split a cold stream.

The vortex tube was invented in 1933 by French physicist Georges J. Ranque. The German physicist Rudolf Hilsch improved the design and published a highly regarded publication.

Construction and operation

Pressurized gas (usually air) is injected tangentially into a swirl chamber, set in rapid rotation ( about 1.000.000/min ) and leaves the chamber through differently shaped axial outlets:

• Through the narrow bore (pictured left) was observed from cooled air
• Through the opposite hole with considerably larger diameter hot air comes out.

The temperature difference is - depending on the structure and gas pressure - at about 40 Kelvin. This produces a characteristic whistle of about 3 kHz with an enormous volume ( about 120 dB).

Function

In the chamber, very high centrifugal forces that can not accomplish alone the observed separation in a warm outer and an inner cold stream. What is certain is that the very loud beep means not yet fully understood processes is necessary because once this is attenuated by absorbing coupled resonators, the temperature difference is reduced to only a few degrees.

Vortex tubes have very low compared to conventional cooling methods efficiency, however, are used for inexpensive spot cooling, when compressed air is available and the noise is tolerable. Commercial models for industrial applications can generate a temperature gradient of about 45 Kelvin.

If it is used for cooling at a drilling or rotary machine for metal cutting, eliminating the otherwise necessary cleaning of adhering liquid coolant.

With incompressible media such as liquids, the vortex tube works only severely limited.