Vortex tube: The vortex tube, also known as the Ranque – Hilsch vortex tube. It separates compressed air into hot and cold streams. It has no moving parts. This device can produce cooling only up to 0.5 TR. Pressurized air is injected tangentially into a swirl chamber. There it acquires RPM of 100000. There is a conical obstruction at the right end of the tube. only the outer portion of the compressed gas is allowed to escape at the right end. The remaining gas is forced to return in an inner vortex of reduced diameter. This is ‘cold’ air and leaves from the left end (where nozzles are fitted). Minimum -500 C can be achieved by Vortex tube refrigeration.
SAMPLE SPECIFICATIONS FOR A VORTEX TUBE
Tube Diameter 25 mm
Length of tube 500 mm
Material Stainless steel
Pressure of air 7 bar
Number of nozzles 8
Vortex RPM generated 100000 RPM
Lowest temperature achieved -70C
Cooling Capacity 0.5 TR.
1. Cooling during machining
2. Spot cooling of electronic components and electronic equipment’s
3. Body cooling of the workers in mines.
4. Hot air can be used for drying purposes.
ADVANTAGES OF VORTEX TUBE
(i) Maintenance free (no moving parts)
(ii) Simple in design
(iii) No controls
(vi) Light weight
(viii) Durable because of stainless steel tube
(ix) Adjustable temperature
(x) Instant cooling
(xi) Uses air as a refrigerant
(xi) Initial and maintenance expenses are also less, where compressed air is readily available
(xiii) Skilled labor is not required.
DISADVANTAGES OF VORTEX TUBE
(i) Low COP
(ii) limited capacity
(iii) Only small fraction of the compressed air is available as cold air.
(iv) Use is limited as it requires compressed air and hence needs an air compressor.