For the term 'vortex-tube' used in fluid dynamics please see: vorticity
The vortex tube, also known as the Ranque-Hilsch vortex tube, is a
mechanical device that separates a compressed gas into hot and cold
streams. The air emerging from the "hot" end can reach temperatures of 200 °C,
and the air emerging from the "cold end" can reach -50 °C. It has no moving
parts. Pressurized gas is injected tangentially
into a swirl chamber and accelerated to a high rate of rotation. Due to the
conical nozzle at the end of the tube, only the outer shell of the compressed
gas is allowed to escape at that end. The remainder of the gas is forced to
return in an inner vortex of reduced diameter within the outer vortex.
Method of operation To explain the temperature separation in
a vortex tube, there are two main approaches:
= Fundamental Approach: The Physics of Vortex Tubes =
This approach is based on first-principles physics alone and is
not limited to vortex tubes only, but applies to moving gas in general. It
shows that temperature separation in a moving gas is due only to enthalpy
conservation in a moving frame of reference.
The main physical phenomenon of the vortex tube is the temperature
separation between the cold vortex core and the warm vortex periphery. The
"vortex tube effect" is fully explained with the work equation of Euler, also
known as Euler's turbine equation, which can be written in its most general
vectorial form as: where is the total, or stagnation
temperature of the rotating gas at radial position , the absolute gas
velocity as observed from the stationary frame of reference is denoted with ; the
angular velocity of the system is and is the isobaric heat capacity of the
gas. This equation has been published in 2012; it explains the fundamental
operating principle of vortex tubes. The search for this explanation began in
1933 when the vortex tube was discovered and continued for more than 80 years.
The above equation is valid for an adiabatic turbine passage; it clearly
shows that while gas moving towards the center is getting colder the peripheral
gas in the passage is "getting faster". Therefore, vortex cooling is due to
angular propulsion. The more the gas cools by reaching the center, the more
rotational energy it delivers to the vortex and thus the vortex rotates even
faster. This explanation stems directly from the law of energy conservation.
Compressed gas at room temperature is expanded in order to gain speed through
a nozzle; it then climbs the centrifugal barrier of rotation during which energy
is also lost. The lost energy is delivered to the vortex, which speeds
its rotation. In a vortex tube, the cylindrical surrounding wall confines
the flow at periphery and thus forces conversion of kinetic into internal
energy, which produces hot air at the hot exit.
Therefore, the vortex tube is a rotorless turboexpander. It consists of
a rotorless radial inflow turbine and a rotorless centrifugal compressor. The
work output of the turbine is converted into heat by the compressor at the hot
end. = Phenomenological Approach =
This approach relies on observation and experimental data. It is specifically
tailored to the geometrical shape of the vortex tube and the details of its flow
and is designed to match the particular observables of the complex vortex tube
flow, namely turbulence, acoustic phenomena, pressure fields, air
velocities and many others. The earlier published models of the vortex tube are
phenomenological. They are: (1) Radial pressure difference:
centrifugal compression and air expansion
(2) Radial transfer of angular momentum (3) Radial acoustic streaming of energy
(4) Radial heat pumping More on these models can be found in
recent review articles on vortex tubes,. The phenomenological models were
developed at an earlier time when the turbine equation of Euler was not
thoroughly analyzed; in the engineering literature, this equation is studied
mostly to show the work output of a turbine; while temperature analysis is
not performed since turbine cooling has more limited application unlike power
generation, which is the main application of turbines.
Phenomenological studies of the vortex tube in the past have been useful in
presenting empirical data. However, due to the complexity of the vortex flow
this empirical approach was able to show only aspects of the effect but was
unable to explain its operating principle. Dedicated to empirical
details, for a long time the empirical studies made the vortex tube effect
appear enigmatic and its explanation - a matter of debate.
History The vortex tube was invented in 1933 by
French physicist Georges J. Ranque. German physicist Rudolf Hilsch improved
the design and published a widely read paper in 1947 on the device, which he
called a Wirbelrohr. The vortex tube was used to separate gas mixtures, oxygen
and nitrogen, carbon dioxide and helium, carbon dioxide and air in 1967 by
Linderstrom-Lang. Vortex tubes also seem to work with liquids to some
extent, as demonstrated by Hsueh and Swenson in a laboratory experiment where
free body rotation occurs from the core and a thick boundary layer at the wall.
Air is separated causing a cooler air stream coming out the exhaust hoping to
chill as a refrigerator. In 1988 R.T.Balmer applied liquid water as the
working medium. It was found that when the inlet pressure is high, for instance
20-50 bar, the heat energy separation process exists in incompressible vortex
flow as well. Note that this separation is only due to heating; there is no
longer cooling observed since cooling requires compressibility of the working
fluid. Efficiency
Vortex tubes have lower efficiency than traditional air conditioning equipment.
They are commonly used for inexpensive spot cooling, when compressed air is
available. Applications
= Current applications = Commercial vortex tubes are designed for
industrial applications to produce a temperature drop of up to 71 °C. With no
moving parts, no electricity, and no Freon, a vortex tube can produce
refrigeration up to 6,000 BTU/h using only filtered compressed air at 100 PSI.
A control valve in the hot air exhaust adjusts temperatures, flows and
refrigeration over a wide range. Vortex tubes are used for cooling of
cutting tools during machining. The vortex tube is well-matched to this
application: machine shops generally already use compressed air, and a fast
jet of cold air provides both cooling and removal of the "chips" produced by
the tool. This completely eliminates or drastically reduces the need for liquid
coolant, which is messy, expensive, and environmentally hazardous.
See also Helikon vortex separation process
Maxwell's demon Windhexe
References = Further reading =
G. Ranque, Expériences sur la Détente Giratoire avec Productions Simultanées
d'un Echappement d'air Chaud et d'un Echappement d'air Froid, J. de Physique
et Radium 4(7)(1933) 112S. H. C. Van Ness, Understanding
Thermodynamics, New York: Dover, 1969, starting on page 53. A discussion of the
vortex tube in terms of conventional thermodynamics.
Mark P. Silverman, And Yet it Moves: Strange Systems and Subtle Questions in
Physics, Cambridge, 1993, Chapter 6 Samuel B. Hsueh and Frank R.
Swenson,"Vortex Diode Interior Flows," 1970 Missouri Academy of Science
Proceedings, Warrensburg, Mo. C. L. Stong, The Amateur Scientist,
London: Heinemann Educational Books Ltd, 1962, Chapter IX, Section 4, The
"Hilsch" Vortex Tube, p514-519. J. J. Van Deemter, On the Theory of the
Ranque-Hilsch Cooling Effect, Applied Science Research 3, 174-196.
Saidi, M.H. and Valipour, M.S., "Experimental Modeling of Vortex Tube
Refrigerator", J. of Applied Thermal Engineering, Vol.23, pp. 1971–1980,
2003. Valipour MS, and Niazi N, "Experimental
modeling of a curved Ranque–Hilsch vortex tube refrigerator", International
Journal of Refrigeration, vol.34(4),1109-1116,
.(http:dx.doi.orgj.ijrefrig.2011.02.013) M. Kurosaka, Acoustic Streaming in
Swirling Flow and the Ranque-Hilsch Effect, Journal of Fluid Mechanics,
1982, 124:139-172 M. Kurosaka, J.Q. Chu, J.R. Goodman,
Ranque-Hilsch Effect Revisited: Temperature Separation Traced to Orderly
Spinning Waves or 'Vortex Whistle', Paper AIAA-82-0952 presented at the
AIAA/ASME 3rd Joint Thermophysics Conference
Gao, Chengming. Experimental Study on the Ranque-Hilsch Vortex Tube. Eindhoven
: Technische Universiteit Eindhoven. ISBN 90-386-2361-5.
R. Ricci, A. Secchiaroli, V. D’Alessandro, S. Montelpare. Numerical
analysis of compressible turbulent helical flow in a Ranque-Hilsch vortex
tube. Computational Methods and Experimental Measurement XIV, pp.
353–364, Ed. C. Brebbia, C.M. Carlomagno, ISBN 978-1-84564-187-0.
A. Secchiaroli, R. Ricci, S. Montelpare, V. D’Alessandro. Fluid Dynamics Analysis
of a Ranque-Hilsch Vortex-Tube. Il Nuovo Cimento C, vol.32, 2009, ISSN 1124-1896.
A. Secchiaroli, R. Ricci, S. Montelpare, V. D’Alessandro. Numerical simulation of
turbulent flow in a Ranque-Hilsch vortex-tube. Int. J. of Heat and Mass
Transfer, Vol. 52, Issues 23-24, November 2009, pp. 5496–5511, ISSN
0017-9310. N. Pourmahmoud, A. Hassanzadeh, O.
Moutaby. Numerical Analysis of The Effect of Helical Nozzles Gap on The
Cooling Capacity of Ranque Hilsch Vortex Tube. Int. J. of Refrigeration, Vol. 35,
Issue 5, 2012, pp. 1473–1483, ISSN 0140-7007.
[1] M. G. Ranque, 1933, “Experiences sur la detente giratoire avec production
simulanees d’un echappement d’air chaud et d’air froid”, Journal de Physique et
le Radium, Supplement, Vol. 7, No. 4, pp. 112–114.
[2] R. Hilsch, 1947, “The Use of the Expansion of Gases in a Centrifugal
Field as Cooling Process”, The Review of Scientific Instruments, Vol. 18, No. 2,
pp. 108–113. [3].J Reynolds, 1962, “A Note on Vortex
Tube Flows”, Journal of Fluid Mechanics, Vol. 14, pp. 18–20.
[4]. T. T. Cockerill, 1998, “Thermodynamics and Fluid Mechanics of a
Ranque-Hilsch Vortex Tube”, Ph.D. Thesis, University of Cambridge,
Department of Engineering. [5] W. Fröhlingsdorf, and H. Unger,
1999, “Numerical Investigations of the Compressible Flow and the Energy
Separation in the Ranque-Hilsch Vortex Tube”, Int. J. Heat Mass Transfer, Vol.
42, pp. 415–422. [6] J. Lewins, and A. Bejan, 1999,
“Vortex Tube Optimization Theory”, Energy, Vol. 24, pp. 931–943.
[7] J. P. Hartnett, and E. R. G. Eckert, 1957, “Experimental Study of the
Velocity and Temperature Distribution in a high-velocity vortex-type flow”,
Transactions of the ASME, Vol. 79, No. 4, pp. 751–758.
[8] M. Kurosaka, 1982, “Acoustic Streaming in Swirling Flows”, Journal of
Fluid Mechanics, Vol. 124, pp. 139–172. [9] K. Stephan, S. Lin, M. Durst, F.
Huang, and D. Seher, 1983, “An Investigation of Energy Separation in a
Vortex Tube”, International Journal of Heat and Mass Transfer, Vol. 26, No. 3,
pp. 341–348. [10] B. K. Ahlborn, and J. M. Gordon,
2000, “The Vortex Tube as a Classical Thermodynamic Refrigeration Cycle”,
Journal of Applied Physics, Vol. 88, No. 6, pp. 3645–3653.
[11] G. W. Sheper, 1951, Refrigeration Engineering, Vol. 59, No. 10, pp.
985–989. [12] J. M. Nash, 1991, "Vortex Expansion
Devices for High Temperature Cryogenics", Proc. of the 26th
Intersociety Energy Conversion Engineering Conference, Vol. 4, pp.
521–525. [13] D. Li, J. S. Baek, E. A. Groll, and
P. B. Lawless, 2000, “Thermodynamic Analysis of Vortex Tube and Work Output
Devices for the Transcritical Carbon Dioxide Cycle”, Preliminary Proceedings
of the 4th IIR-Gustav Lorentzen Conference on Natural Working Fluids at
Purdue, E. A. Groll & D. M. Robinson, editors, Ray W. Herrick Laboratories,
Purdue University, pp. 433–440. [14] H. Takahama, 1965, “Studies on
Vortex Tubes”, Bulletin of JSME, Vol. 8, No. 3, pp. 433–440.
[15] B. Ahlborn, and S. Groves, 1997, “Secondary Flow in a Vortex Tube”, Fluid
Dyn. Research, Vol. 21, pp. 73–86. [16] H. Takahama, and H. Yokosawa, 1981,
“Energy Separation in Vortex Tubes with a Divergent Chamber”, ASME Journal of
Heat Transfer, Vol. 103, pp. 196–203. [17] M. Sibulkin, 1962, “Unsteady,
Viscous, Circular Flow. Part 3: Application to the Ranque-Hilsch Vortex
Tube”, Journal of Fluid Mechanics, Vol. 12, pp. 269–293.
[18] K. Stephan, S. Lin, M. Durst, F. Huang, and D. Seher, 1984, “A Similarity
Relation for Energy Separation in a Vortex Tube”, Int. J. Heat Mass
Transfer, Vol. 27, No. 6, pp. 911–920. [19] H. Takahama, and H. Kawamura, 1979,
“Performance Characteristics of Energy Separation in a Steam-Operated Vortex
Tube”, International Journal of Engineering Science, Vol. 17, pp.
735–744. [20] G. Lorentzen, 1994, “Revival of
Carbon Dioxide as a Refrigerant”, H&V Engineer, Vol. 66. No. 721, pp. 9–14.
[21] D. M. Robinson, and E. A. Groll, 1996, “Using Carbon Dioxide in a
Transcritical Vapor Compression Refrigeration Cycle”, Proceedings of the
1996 International Refrigeration Conference at Purdue, J. E. Braun and E.
A. Groll, editors, Ray W. Herrick Laboratories, Purdue University, pp.
329–336. [22] W. A. Little, 1998, “Recent
Developments in Joule-Thomson Cooling: Gases, Coolers, and Compressors”, Proc.
Of the 5th Int. Cryocooler Conference, pp. 3–11.
[23] A. P. Kleemenko, 1959, “One Flow Cascade Cycle”, Proceedings of the 10th
International Congress on Refrigeration, Pergamon Press, London, p. 34.
[24] J. Marshall, 1977, “Effect of Operating Conditions, Physical Size, and
Fluid Characteristics on the Gas Separation Performance of a
Linderstrom-Lang Vortex Tube”, Int. J. Heat Mass Transfer, Vol. 20, pp. 227–231
[25] s.chhimpa ,Dr. vikas bansal "application of vortex tube in
refrigeration " External links
G. J. Ranque's U.S. Patent Detailed explanation of the vortex tube
effect with many pictures Oberlin college physics demo
Articles On Vortex Tube