Thermodynamics
> Entropy and the Second Law > Entropy
DCS#
4F10.30
HILSCH-RANQUE
VORTEX
TUBE
APPARATUS
Hilsch-Ranque vortex tube
202-11-B
compressed air supply
201A
thermocouple probe with digital
display
ask John
DESCRIPTION
Connect the hose to the compressed
air supply
and open the valve all the way. The tube separates the faster and
slower moving molecules in the incoming airstream and sends them to
opposite
exits. Use the thermometer to show that colder air comes out the
short end of the tube and warmer air comes out the long end. Tc
< 0° C is easily obtained.
NOTES
The air enters the tube
directed
tangentially
and follows a vortical path with faster moving molecules at the outer
radii
and slower ones at inner radii. The hot air exhaust is at the
circumference
of the tube and the cold air exhaust is at the center.
The airflow at the hot air
outlet is
adjustable.
Opening up the valve reduces the fraction of air ejected from the cold
air exhaust and lowers its temperature. Closing it down results
in
less but hotter hot air.
REFERENCES
R. Hilsch, The Use of the
Expansion of
Gases
in A Centrifugal Field as Cooling Process, The Review of Scientific
Instruments,
vol. 18(2), 108-1113, (1947).
C. L. Stong, The "Hilsch" Vortex Tube,
The
Amateur Scientist, Scientific American, 514-519.
J. J. Van Deemter, On the Theory of
the Ranque-Hilsch
Cooling Effect, Applied Science Research 3, 174-196.
