vortex tubes

Hi Tommy,

I've used and studied vortex tubes but found that there are more applications than explanations regarding it. Wikipedia sums it up nicely (vortex_tubes).

How much pressure? As much as you have! The higher the pressure, the greater the temperature difference between the hot and cold end. Whether this is true at all pressures, I don't know since I've never experimented that far.

With regards to temperature, manufacturers claim that it can go as low as -40°C at the cold end.

Perhaps you could try visiting some manufacturer's websites:

exair

arizonavortex

Please go to Spirax Sarco site - Spirax Learing, Check Modules 4.1 thru 4.3 on Flow Meters. Here you will find all related description on working & all formulas you can ever think of. Trust these will answer all your question.

We purchased ours from Exair and use them to keep our computers cool as they are in sealed cabinets and would quickly overheat without them. In our application, 60 psi works best with the following variables: cooling unit size and type, cabinet size, ambient temperature, and the amount of heat generated by the pc.

Important tip. Make sure that the air supplied is filtered and dried.( That wasn't meant to rhyme. :) )

I knew about them but I never tried one. Wikipedia is saying that cascaded vortex tubes can be used for reaching cryogenic temperatures. Does anyone have knowledge on this? I think it's quite a challenge as most likely the cold output is low pressure and for cascading them a new compression is required which rises the temperature...

I believe we had a forum on this about a year ago. I did my Bachelor's project on this topic about 40 years ago...

I think the best way to think of it is this: A stream of air is injected tangentially off center. the cylindrical shape of the tube causes this air to follow a spiral path. The air molecules came in with the same average linear velocities, so those molecules that happen to be nearer the center must initially have higher angular velocities than those near the outside. Frictional forces will try to slow down the high RPM molecules near the center and speed up the low RPM molecules farther out, to approach a single mass with the same RPM everywhere. This transfers energy from the center towards the outside; slow molecules = cold; fast molecules = hot.

Unfortunately, unless you already have a large supply of compressed air available, and can ignore the cost of compressing the air, they are expensive to run, and they are noisy. For most small cooling jobs, I like the Peltier effect devices better (although their efficiencies are also rather low, at least they are silent, except for a cooling fan).