Vortex tube

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

The principle of operation

Georges J. Ranque discovered the effect in 1928 and published it in 1933. In 1946, Rudolf Hilsch delivered the first physical systematic publication based on Ranque's discovery. Due to the improvements in Ranque's construction and the value of his work, the vortex tube effect is now known as the "Ranque-Hilsch vortex tube effect".

Construction and operation

Gas under pressure (mostly air) is blown tangentially into a round vortex chamber and thus set into rapid rotation (over 1,000,000 / min). The gas leaves the chamber through differently designed axial air outlets:

  • Cooled air escapes through the narrow hole (on the left in the picture)
  • hot air escapes through the opposite hole with a considerably larger diameter.

The temperature difference is - depending on the structure and gas pressure - over 40  Kelvin . This creates a characteristic whistling tone of around 3  kHz with a volume of around 120 dB .

function

Very high centripetal forces occur in the chamber , which alone cannot achieve the observed separation into an outer warm and an inner cold stream. It is certain that the very loud whistling sound is necessary due to processes that are not yet fully understood, because as soon as it is dampened by coupled absorbing resonators , the temperature difference is reduced to only a few Kelvin.

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

If it is used for cooling on a drilling or lathe for metal cutting, the otherwise necessary cleaning of adhering liquid coolant is not necessary.

The vortex tube only functions to a very limited extent with incompressible media such as liquids .

See also

literature

  • G. Ranque: Expériences sur la Détente Giratoire avec Productions Simultanées d'un Echappement d'air Chaud et d'un Echappement d'air Froid. In: J. de Physique et Radium 4 (7) (1933) 112S.
  • Rudolf Hilsch: The Use of the Expansion of Gases in A Centrifugal Field as Cooling Process. In: The Review of Scientific Instruments , vol. 18 (2), pp. 108-13, (1947). translation of an article in time. Natural science . 1 (1946) p. 208.
  • Rudolf Hilsch: The expansion of gases in the centrifugal field as a cold process. In: Zeitschrift für Naturforschung , Vol. 1 (1946), pp. 208-213
  • HC Van Ness: Understanding Thermodynamics , New York: Dover, 1969, starting on page 53. A discussion of the vortex tube in terms of conventional thermodynamics.
  • CL Stong: The Amateur Scientist , London: Heinemann Educational Books Ltd, 1962, Chapter IX, Section 4, The "Hilsch" Vortex Tube, pp. 514-519.
  • JJ van Deemter : On the Theory of the Ranque-Hilsch Cooling Effect. In: Applied Science Research 3, 174-196.
  • MH Saidi and MS Valipour: Experimental Modeling of Vortex Tube Refrigerator. In: Journal of Applied Thermal Engineering Volume 23, 2003, pp. 1971-1980.
  • RT Balmer: Pressure-driven Ranque-Hilsch temperature separation in liquids. In: Trans. ASME, J. Fluids Engineering 110, June 1988, pp. 161-164.
  1. ^ Mark P. Silverman: And Yet it Moves: Strange Systems and Subtle Questions in Physics , Cambridge, 1993, Chapter 6

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