Talk:Vortex tube

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SEVERE PLAIGERISM!

This entire article, even including formatting, was ripped from [1]. I'm not sure exactly how to do this, but someone should at least cite it...

-Leif

Actually , it's the other way around :) Look at the small print at the bottom of the page you referenced. Duk 16:40, 1 Mar 2005 (UTC)


Contents

[edit] Questionable claim

I question this claim under the references:

    • Van Ness, H.C. Understanding Thermodynamics, New York: Dover, 1969, starting on page 53. A discussion of the vortex tube in terms of conventional thermodynamics, which is able to explain it completely.

For this to be true in 1969 is very unlikely as there are many papers in the 1990s that cannot even claim this. I haven't read the reference in question, however, so I cannot disbute it directly. X2-PB 10:29, 19 August 2005 (UTC)

I don't think it's unreasonable to remove the text, at least on the simple grounds that it does not substantially aid the reader in understanding the topic. -- Taral 19:59, 12 September 2005 (UTC)

Please give some references that claim it is not understood. The point is that it does not contradict the laws of thermodynamics. GangofOne 00:41, 13 September 2005 (UTC)
It is true that it doesn't contradict the laws of thermodynamics, but those laws do not explain the mechanism behind the temperature separation within the tube. This is the point I was making. The latest authors atribute the effect to a number of different causes and it is likely that it is the result of a summation of different mechanisms all occuring at once. X2-PB 12:09, 9 October 2005 (UTC)

[edit] Link to Slashdot discussion?

Is the link to a Slashdot discussion really relevant? I don't think it's "encyclopedical"... or else we would go around adding Slashdot links to Wikipedia articles in whatever subject they discuss there. I suggest removing it. -- LodeRunner 22:23, 12 September 2005 (UTC)

I agree. Let's archive the link to the Slashdot discussion here. After all, it's just another discussion  Quicksilver 05:06, 9 October 2005 (UTC)

[edit] References

The Scientific American article reference is apparently from the 1960 book by that title (out of print since 1972), compiled by C.L. Stong and published by Simon and Schuster. Stong served as editor of the Amateur Scientist column from 1954 until his death in 1977. If anyone has access to a copy of the book, a complete, correct citation for the article would be appreciated. A new anthology of Amateur Scientist articles from the 1920's to 1999 is now available on CD ROM, published by Tinkers Guild (2002) ISBN: 0970347626. Available from Amazon.com  Quicksilver 05:06, 9 October 2005 (UTC)

Done. No one should be without a copy of this excellent book. -- Derek Ross | Talk 20:27, 9 October 2005 (UTC)


There's a date discrepancy between the article and the Reference about Rudolf Hilsch's article. The article states 1945, the Reference 1947. Which is correct?  Quicksilver 05:15, 9 October 2005 (UTC)

The referenced article is a translation of the original. The translation was indeed published in 1947, but I don't know about the original. Itsallgroovy 15:21, 15 January 2007 (UTC)

[edit] how it works

So, how does it work? --DavidCary 07:20, 6 January 2006 (UTC)

the outer vortex spins toward the "hot" end of the tube, picking up energy from the inner vortex which is returning from the hot end and going toward the cold end, there are plenty of theories why the inner vortex loses energy while the outer vortex gains it when the law of conservation of angular momentum means the inner one should gain energy, the easiest to understand is an ultrasonic "hum" forms from the vortices moving at arguably a million RPM, and it is this "hum" that shuffles higher energy molecules out to the outer vortex and lower energy molecules to the inner vortex due to the difference in sound moving through warmer and/or colder materials. But like I said, Theory, in reality.... no one REALLY knows how these damned things work, lot of good ideas, but in the end it's a mystery, especially since the phenomenon doesn't occur with water, although that might be more of an issue with thermodynamics, or viscosity, or a thousand other laws of reality. --Munky--68.124.106.93 00:16, 4 February 2006 (UTC)
I believe it does work with water, or atleast there is evidence that it does, but because of the higher viscosity of water it means that a water vortex tube has to be pretty huge.WolfKeeper 23:32, 24 October 2006 (UTC)
It works with water to a very small extent. I believe the maximum temperature seperation is only a few degrees whereas, with air, a variation of over 60 degrees can be achieved. It is thought that the heating effect reported with water is actually due to a different mechanism altogether. The main reason that the mechanism (for air) is not known for certain is that is is the result of a combination of a number of different mechanisms, some of these are laminar, some are turblent. It is possible, however, to accurately model the effect using CFD codes and so, with enough research, it may be possible to exactly discover the presice mechanism(s) causing the effect. X2-PB 19:25, 1 June 2007 (UTC)
I didn't see specs on performance (if they exist). What diameter & length would be required to get the 45°C Δt quoted? Trekphiler 16:55, 26 July 2007 (UTC)

[edit] Heat Pump

The definition of a heat pump is a device which uses work to move heat from one resevoir to another. The vortex tube, however, uses neither work nor heat transfer in its system. Given this, and the recent modifications to this article, I question whether or not the vortex tube is a heat pump.

In order for it to run, it needs a compressor to blow the air into it. That takes work. If you run a tube from the cold pipe leading from the vortex tube, then you can use that tube to cool things. Meanwhile the hot pipe can be used to heat things. Hence it is a heat pump.WolfKeeper 23:29, 24 October 2006 (UTC)
You beat me to it, Wolfkeeper. I was about to say the same thing. I'll just add that without a pump to compress the input gas, a vortex tube is just a pipe with a hole in the side. -- Derek Ross | Talk 23:49, 24 October 2006 (UTC)
These arguments show two glaring misconceptions about thermodynamics. One, you claim that the compressed air requires work. This is true, it does require work to compress air. This means that there is a compressor linked up to this tube compressing air, and that the compressor is doing work on the air before it enters the vortex tube. The tube itself exerts no work on the air.
Really? So you are seriously claiming that energy due to the pressure of the hot and cold sides of the vortex tube is exactly equal to the energy of the supply? I find that difficult to believe. I think that the hot side of the vortex tube is hotter than the cold side is cold. That's because of waste heat generated due to viscosity in the tube. So work has been done there at the very least. And from the reversibility of the Carnot cycle we know that it cannot exceed the efficiency of the Carnot cycle (otherwise you could build a perpetual motion machine). In practice, the vortex tube is *very* inefficient, so it doesn't get anywhere near that point.WolfKeeper 05:41, 28 October 2006 (UTC)
Two, you claim that because "the hot pipe can be used to heat things" and the cold pipe can be used to cool things, there is heat transfer. This is not heat transfer into or out of the system. You seem to be mistaking heat with temperature. Yes the temperature at the inlet and the two outlets is different, but the overall heat of all the air in the control volume of the vortex tube remains constant. This is the thermodynamic definition of heat transfer.
Also, if the hot air were to heat another system, that would be after it was out of the system of the vortex tube. You can't consider effects of what the mass does once its out of the system (or before it's in the system, from your compressor argument) to be heat transfer or work done while in the system.
But we don't have to let the air exhaust to atmosphere and thus leave the system. We just have to pipe it from the ends of the vortex tube (after it's heated/cooled the external reservoirs via conduction through the walls of the vortex tube) and feed it back into the pump inlet. That makes the system much easier to analyse and removes your objection about mass leaving the system. Now only heat and work can enter and leave the system: the former entering/leaving via the cold/hot end walls of the vortex tube; the latter via the pump. -- Derek Ross | Talk 05:33, 28 October 2006 (UTC)
69.174.226.202 if you want to be really anal about it, the vortex tube isn't in itself, on its own, a heat pump, but you can add the cold sink heat exchanger, the hot source heat exchanger and plumbing to mix the hot and cold airstreams back together again before going through the air pump and the vortex tube, and then it is. But everybody knows all that, "so quit buggin' me man".WolfKeeper 05:46, 28 October 2006 (UTC)

I've revised the into to remove pro/anti heat pump claims. Let's find good references and cite them properly before re-adding (I don't have access the current references or I would look myself). --Duk 20:21, 9 November 2006 (UTC)