Vortex tubes, Injection, Turbos, Cold air. *concept

[tr8er]

So 97_Luder posted his 3D Printed carb horns, and it had a unique feature to reduce turbulence.  Fins to spiral the intake air.  Which I believe was a good idea, and it got me thinking about vortex tubes.

 

explanation of a Vortex Tube:  http://www.newmantools.com/vortex.htm

 

Effectively, this is a means of cooling air with nothing more than compressed air.  You can get down to the -40's with commercially available products.  

 

 

 

It is my understanding that cold air is denser, therefore holds more oxygen in a given volume.  Thus, if you can cool the air going into the engine, you can increase power, and efficiency.  Now the need arises for compressed air.  Installing a compressor would not likely create a net gain.  Possibly on performance, but certainly not efficiency as this compressor will rob power from the engine.  Fortunately some gear heads have already figured this need for compressed air out.  And that is where the Turbo comes in.  Installing a turbo will produce pressurized air, and could, in theory, drive a vortex tube.  A vortex tube creates hot and cold air from regular air.  Dump the hot air, and send the cold air into the intake manifold.  With injection, and a robust management system, I see this working.  You would be sending freezing cold air into the pressurized turbo'd intake, or just run non turbo intake, utilizing the turbo exclusively for the vortex tube.  Depending on the amount of compressed air needed, a larger turbo may be required.  

 

I'm going to guess more than one of you find fault in this, so please point them out.  I don't know much about turbos, or injection.  But I've long had a thing for the vortex tube design principle.  

 

 

Quick explaination from Newman tools website:

 

Operation

Any fluid that flows and rotates about an axis such as a tornado, is called a vortex. A vortex tube creates a vortex and separates it into two air streams-one hot and one cold. Figure 1 shows how a vortex tube works. Compressed air enters a cylindrical generator which is proportionately larger than the hot (long) tube. The generator causes the air to spiral. The spiraling air is forced down the inner walls of the hot tube at speeds reaching 1,000,000 rpm. At the end of the hot tube, a small portion of this air exits through a needle valve as hot air. The remaining air is forced back through the center of the incoming air stream but at a slower speed. The heat in slower moving air is transferred to the faster moving incoming air. This super-cooled air flows through the center of the generator and exits through the cold air exhaust port. 



Temperature Separation Effects

The Vortex Tube Creates two types of vortices: free and forced. In a free vortex (like a whirlpool) the angular velocity of a fluid particle increases as it moves toward the Center of the vortex-that is, the closer a particle of fluid is to the center of a vortex, the faster it rotates. In a forced vortex, the velocity is directly, proportional to the radius of the vortex-the closer the center, the slower the velocity. 



In a vortex tube, the outer (hot) air stream is a free vortex. The inner (cold) air stream is a forced vortex. The rotational movement of the forced vortex is controlled by the free vortex (hot air stream). The turbulence of both the hot and cold air streams cause the layers to be locked together in a single, rotational mass. 



The inner air stream flows through the hollow core of the outer air stream at a slower velocity than the outer air stream. Since the energy is proportional to the square of the velocity, the cold air stream loses its energy by heat transfer. This allows energy to flow from the inner air stream to the outer air stream as heat creating a cold inner air stream.

 

 

[ggzilla]

Just be carefully that the air goes straight through the carburetor's venturis for accurate metering.

[smoke]

It's interesting for sure. It gets into a complex area really. There is no argument the hot air costs some power even on a naturally aspirated car. Guys still pack the the sides of their intake with dry ice at the track to avoid heat soak. As you said, hot air the molecules are further apart, thus holding less power than a really cold charge. This really makes a HUGE difference on a turbo engine, the compressed air on a run of the mill turbo engine is normally 250 to 300 degrees and gets much higher in some applications. Which is why we use intercoolers and then try to turn the intercooler into a block of ice before a pass.

 

A couple of things to keep in mind though, if that was set up before the throttle blade, the air would need to be straightened out before hand. Also, the none wide open parts to your driving may be effected in a bad way. Anyone who has had a car or truck that has a carb icing issue know about this. BUT, with injection, as you mentioned this is not going to be much of a concern. I feel it may hold some benefit to an NA engine, but I personally don't think it would be much of one. Not enough to justify the effort. Still would be kinda fun to do. 

[tr8er]

I'm guessing the gains will be minimal.  But the folks who are packing ice on their inter-coolers could get all their jollies, and perhaps get far colder air without all to the dry ice humbug.  Dry ice is fun an all, but having this built into the engine and managed appropriately could fine tune the temperature and maximize one more aspect of combustion.  considering the part is cheap, the efficiency gain could quickly pay for the part.  (only after R&D of course).

[smoke]

I say it's worth some further thought.

[datzenmike]

This example works at 100 PSI not one or two Bar. A good inter cooler would be simpler and more efficient. Interesting, probably not too practical.

[smoke]

BUT............if you where running 100 pounds of boost, awesome.

[datzenmike]

That will be the day. Still for a race car application where even 0.5% more power is an edge it might.

[tr8er]

The pressure capacity of a turbo is one thing I did not have a firm grip on.  Sounds like a huge step to get 100psi from a turbo.  This sounds like a buzz kill on the concept. 

 

Vortex tubes are so fucking bad-ass though.   

[smoke]

It can be done, but yeah, it's nutty. Some of those Cummins they drag race and sled pull run 150 plus psi.

[datzenmike]

Well that's 100 PSI in but hot air is bled out so what's the cold air pressure out? Might be manageable.

[smoke]

6

[DanielC]

You cannot get something for nothing.  There is no such thing as perpetual motion.  It will take more energy to compress the air, than the power gains from using the compressed air to eventually cool the inlet charge.  Compressing the air heats it up.  You also get additional heating of the air, if you use a turbocharger, because of the temperature of the exhaust turbine, that drives the compressor wheel.

 

Yes, in some cases a turbocharger can capture some lost energy from the exhaust gasses.  But there is a price to pay for that.  The exhaust is hotter at the engine, and there is more back pressure.  But in some cases, the intake manifold pressure can be higher than the exhaust manifold pressure, and the turbo is capturing the heat energy in the exhaust gasses. 

 

If you are going to use a turbocharger to compress air, so you can cool it again, it seems to me that is just a additional pumping loss for the engine, without any gain.  Keep in mind, if you take air, at ambient temperature, and compress it, before is is useful for cooling, you have to get it back close to ambient temperature again.   Then you can allow the air to expand, and give you some cooling.

[tr8er]

Daniel, you are right in concept.  The interesting thing about vortex tubes is their ability to divide air into hot and cold as a product of centrifuge.  The cold air output is typically 70% of the input volume.  It is a particularly efficient way of producing cold air.  That said, I'm not proposing you get something for nothing.  It's just a question of if you get enough for what goes in.  

 

I'm thinking 100psi inlet, with 70% cold output would be able to so what is needed with plenty to spare.  Now we just need to utilize the tesla pump turbocharger and we are good to go!

[datzenmike]

What about volume? At 7 PSI boost on an L20B that's about 325 cubic feet per minute.(at 6K) 

[Parkinglotslider521]

I grasp the concept, but what i don't get is the 100 psi to work. I can't see that being a set in stone pressure. Wouldn't the input pressure needed vary upon the size of the vortex tube? Because (correct me if i'm wrong, because i could be very wrong) if my thinking is true, this seems comparable to turbocharger concepts. A larger turbo takes longer to spool, but has higher flow capabilities, whereas a smaller turbo is the opposite. In theory wouldn't you be able to scale down the V.T. which would make it useable with less pressure? obviously it wouldn't flow as much air, but if you ran piping from the cold side to an intake manifold with a regular throttle body, i'm sure the -40 degree air would have some positive effect on cooling the rest of the incoming air. Even if it only dropped the intake temps from 140 to 70, that's one helluva gain imo. 

 

But like i said, i could be the equivalent of a window licker in this thread. I have no knowledge on this, just basing my thinking along the lines of things i do know.

 

One last thought: would it be possible to put a nozzle at the vortex chamber to speed up the incoming air?  like a nozzle that's on a rocket motor? If so wouldn't you need less pressure to generate the vortex? I'm going to do more research, this is one of those rare very technical seeming things that doesn't turn my brain into goo when i think about it.

 

Edit: I cant see this working without miltiple units. The most badass unit Newman tools shows cools inlet air 76 degrees from its original temp, but only consumes 100cfm. so it would only output 70cfm with 100psi of air that would need to be cooled for any major gain. i don't see it being practical.