Hilsch vortex tube

[Guest]

Vortex Tube - From Gyroscope.com -

There you have it! No news to me, sadly....

[Ted Ewert]

A vortex tube is an interesting device. It graphically illustrates the properties of a vortex.
"Modern" physics has a hard time explaining why a temperature variation occurs between the inner and outer parts of the vortex. This is because most physics is taught using the Newtonian model which is based on linear motion. Nothing moves in a straight line in the natural world, it's all curved motion.
All curved motion consists of two forces: centripetal and centrifugal. Again, "modern" physics even denies the very existence of centrifugal force (calling it a phantom force), further hamstringing themselves in the process.
Nevertheless, Nature doesn't listen to physicists and follows her own eternal laws. Her law of duality is present in all of creation. It is the fundamental property of the universe. A vortex is also a fundamental phenomenon, showing us the preferred configuration of all energy.
A hurricane is a good example of a vortex. The centrifugal part of the Hurricane is the part that takes up the vast majority of it's volume. It consists of all the clouds we see spinning in a giant pinwheel from satellite pictures. The centripetal part is the core, which is usually seen as an indentation in the center of the storm.
Although these forces vary greatly in volume, they are absolutely equal in strength. Centrifugal properties include expansion and heating while centripetal properties are primarily implosive and cooling. The volume difference is obvious when viewing a hurricane or a tornado. A tornado is less obvious until you realize that what you see, the opaque vortex extending from the clouds, is only the center of the tornado. The outside centripetal portion is invisible since it only consists of wind. The reason you see the centripetal portion is because of the pressure drop and consequential condensation of the water vapor therein.
In a Hilsch tube the same thing occurs. The outer part of the vortex is expanding and heating. This portion contains the greater volume of air and heats up. The inner part condenses and cools. In the Hilsch tube you'll find that this innermost flow actually rotates counter to the outer flow. This flow has a small volume of air and is cool.
Creating a vortex is easy enough. However, just like spinning a top, it's all about speed. Until a top gets up to a certain rotational speed, it doesn't work so well. It wobbles and moves around, and when it slows down enough, it falls over and doesn't work at all. This is the same with a vortex. A slow moving vortex won't exhibit the same degree of it's properties that a fast moving vortex will. A slow moving vortex in a Hilsch tube won't separate the temperatures worth beans. Speed is everything. That's why they use compressed air. A decent Hilsch tube is rotating at around a million RPM. That's fast. You will be hard pressed to get those speeds with any fan.
You need high pressure air blowing through a small aperture at the periphery of the cylinder, at 90 degrees to the radius. The rotational speed of the vortex will increase exponentially towards the center axis. This is enabled through virtually frictionless coaxial zones that form between the outer and inner regions. Cylinders of air move at different speeds right next to each other with no turbulence created at their boundaries. This is a very important aspect of a vortex, and one many people don't understand. This property also allows a flow of gas or liquid through a pipe with very little resistance, even at high speeds, as long as rapid rotation is maintained. High volumes of air can be moved through a pipe half the usual specified diameter for a normal flow.
Anyway, vortex's are very interesting things and well worth the exploration.



Ted

[Vortex]

Vortex Tube construction details

So what would the best ratio of small hole diameter vs. big tube diameter and tube length be? Why do we need adjustable valves? To adjust the time the air has to separate into hot and cold flows?

This video looks great, especially the cold air "flame"
YouTube - Rank-Hilsch vortex tube

Jetijs,

It's kinda hard to find design details on vortex tubes.
I once came upon a government document study in 1967 on improving vortex
tubes but it cost $60 + $6 handling, only available on paper.

Yes, the adjustment at the Hot End allows the air to stay within the tube
longer and thus you can dial in/out the cold/hot side exit temperatures.

Since energy can not be destroyed, then one should be
able to simply use the equation to determine the exit PSI of each end
of the tube knowing the inlet PSI and Temp, exit temp of cold & hot sides.

A nice document for reference is here.
EXPERIMENTAL RESULTS OF A VORTEX TUBE AIR SEPARATOR
FOR ADVANCED SPACE TRANSPORTATION
Has a design by American Institute of Aeronautics and Astronautics

Another source for details, on Page 428
Analysis Of Heat And Mass Transfer

I'm very interested in this also in relation
to the air engine, but right now don't have time to experiment.
Randy

[Alana]

Hi all,

I know the vortex tube is fascinating. But please note: the COP of this tube is very very low. For example a typical vortex tube and compressor arrangement achieves a Coefficient of Performance of around 0.08 when operated as a domestic refrigerator. Whitout the power for compressing the COP is at about 0,2. Isn't that frustrating?

Regards
Alana

[Vortex]

Hi all,

I know the vortex tube is fascinating. But please note: the COP of this tube is very very low. For example a typical vortex tube and compressor arrangement achieves a Coefficient of Performance of around 0.08 when operated as a domestic refrigerator. Whitout the power for compressing the COP is at about 0,2. Isn't that frustrating?

Regards
Alana

Alana,


There are many types of designs, some better than others and some really bad ones.

This is good information to have, but the context required.
Could you please point us to where you obtained these figures.

My interest involves the use of both the hot and the cold outputs.

Thanks
Randy

[Vortex]

More designs

There's Magical ratios between the cold tube
length and the hot tube length as well as a ratio for the diameter.
The ratios are out there to be found. I've seen them, I just didn't think it would
be very hard to find them so I didn't save them.

Nice design image on Page 3
Text includes diamentions, Plus equations
1, 2 and 4 nozzles data chart

Design Image

Very crude images of multiple designs, I've not seen these designs before on Page 16,
Length ratios given 1/10 and ??1/30?? (I think)

Source link: American Institute of Aeronautics and Astronautics - Electronic Library Search Results
for this Design link

Design Measurements : scroll down, chart has links to details.

The one everyone finds at some point.

and for Grins on Page 6 (no vertex tubes):
200 meter diameter ring vortex from Mt Etna formed
because no solid boundary was nearby
(only looks like a cigarette smoke ring, but 200 M!)

Randy

[Jetijs]

Hi all.
Today I messed around with the vortex tube a bit. I made a simple tube like this:





The tube is 40mm in diameter and 300mm long.
I tried to apply pressurized air to the tube, but all the air just flows out of the hot air side and nothing flows out of the small cold air hole. In fact, the small cold air hole creates suction. I don't have the cone on the hot side, could this be the problem?
Thanks,
Jetijs.

[gmeast]

some old references

There's Magical ratios between the cold tube
length and the hot tube length as well as a ratio for the diameter.
The ratios are out there to be found. I've seen them, I just didn't think it would
be very hard to find them so I didn't save them.

Nice design image on Page 3
Text includes diamentions, Plus equations
1, 2 and 4 nozzles data chart

Design Image


Very crude images of multiple designs, I've not seen these designs before on Page 16,
Length ratios given 1/10 and ??1/30?? (I think)

Source link: American Institute of Aeronautics and Astronautics - Electronic Library Search Results
for this Design link

Design Measurements : scroll down, chart has links to details.

The one everyone finds at some point.

and for Grins on Page 6 (no vertex tubes):
200 meter diameter ring vortex from Mt Etna formed
because no solid boundary was nearby
(only looks like a cigarette smoke ring, but 200 M!)

Randy

Hi all,

These are some old reference images I found from my archives. The pictures show some basic relationships I think.

Greg

[Vortex]

Jetijs,
Most smaller designs of vortex tubes use a chamber for the inlet air which is larger than both hot/cold exits sizes.
I believe all designs reduce the hot tube size at the exit end via a few different methods.
Cold exit is always shorter than the hot exit in length by a certain ratio.
Which has nothing to do with attaining hoses to both or either end of the
vortex tube.

The image at this link shows what I've spoken about.
The inlet chamber is larger dia. than both hot/cold exit tubes.
The cold tube is always shorter, in this image, the cold is smaller dia. than
the hot tube. The hot tube is restricted in dia. at the end .. which is not for adjusting the hot/cold flow. That reduction in the dia. of the hot tube causes the vortex to turn inwards upon itself, the center vortex which travels towards the cold exit.

The YouTube - Rank-Hilsch vortex tube you posted and admired was only
a total length of about two widths of the air gauge used in the video.
The rest of the stuff in the video was added to the ends of the vortex tube.

Think smaller. Your vortex tube looks nice, but man it's really large.

It's only an opinion and observation
Randy

[Jetijs]

Thanks Greg, Randy
For starters I will install a cone on the hot end of my tube. Then, if nothing works, I will try the big inlet chamber idea

[Jetijs]

Ok, I installed a cone on the hot end. But this did not improve anything. All the air still flows out of the hot end holes and the cold end hole still sucks air in. Maybe I need to restrict the air flow from the hot side to some degree?

[Vortex]

As far as I understand how it works, the cone is part of a valve for adjusting / restricting
the hot air flow which controls the hot/cold temperature ratios by not allowing the hot air to freely exit the tube.
This cone/valve does not cause or create the vortex, that I'm aware of.

The narrowing of the hot tube before the cone/valve causes the vortex
moving toward the end of the hot tube to reverse direction and travel back
up the hot tube in the center vortex towards the cold exit.

image of vortex tube.
Reduce the end of the hot tube as seen in the image.
You can always make restriction hole bigger later, but not smaller.
I'd try about 1/2" diameter larger than your cold diameter size first.

What is the diameter of your cold hole?

That's my best guesses.

Randy

[Jetijs]

The diameter of the cold hole is 10mm. I installed an adjustable valve on the hot side holes so that I can restrict the hot side flow. Now if I restrict the hot side flow, a low appears also on the cold end. So far I tried many different levels of restriction, but no great results so far. The input compressed air is a bit cold, but I can put my finger in the input air flow and it feels just cool. If I now put my finger on the hot side, the finger feels just ambient temperature. If I put my finger on the cold end, I can feel freezing sensation. So there is a little temperature difference on both sides, but nothing spectacular. I don't have a thermometer at this time, so I can't give you exact results.
I still do not have a tube on the cold end hole, will glue it on and do some more testing.
Thanks,
Jetijs.

[Stealth]

From what I've found is that the length of the pipe and the valve adjustment is the most critical combination to achieving the right balance for operation. If you can determine a difference in temperature, then you can't be far off in this balance. These things are intricate in their operation.

[gmeast]

my old hilsch vortex tube

Hi all,

Here are some pictures of an old Hilsch tube I made about 10 years ago. It's my first and only attempt at one of these things. I can't believe I was able to actually find it after all of this time.

The hot end with the conical diffuser wafts out air at 103 F to 110 F. The cold end exhausts at about 38 F to 40 F until the compressor heats up then it won't get colder than about 48 F to 50 F. The hot end really doesn't change that much once it's tuned up.

Thanks,

Greg

vortex tube is 10 5/8 in long overall. The body is 3/4 pipe, cold is 1/4 pipe, diffuser is a 3/4 pipe coupling with a double-ended cone suspended in the center by 2 wire pass-through spokes (ends shown bent over)


closer view of the hot end conical diffuser. Diffuser is adjustable for tuning for changes in supply pressure ... just screw it in for less annular area/flow or screw it out for more annular area/flow.