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Forced induction USING air compressor?


xShodaimex

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I get no joy in seeing myself on Ron's post... is there a photo there, or did I really loose a lot of weight and am now invisible? :huh:

 

Prolaxmus, your statement is flawed in that you discount capacitance storage, and the existence of air amplifiers. If you have a 10:1 amplifier, you can take 1 scfm at Xpsi and convert it to 10 scfm at a lower pressure by inducing ambient air into the stream of the amplifier. It's a concept which allows the use of compressed air to cool panels (vortex coolers), as well as provide huge volumes of low pressure air from a single source of high pressure air. Air Conveying of AGM (the stuff in diapers) is a good source of an industrial application of the technology.

 

All you need to know is how much pressure, and at what flow you will need, for what duration and that will dictate the size of the storage vessel. Making 1300CFM (or even 2600cfm) for 10 seconds off 175 or even the A/C compressor 235psig available would not be difficult. It's a limited boosting time, usually seconds, dictated only by pressure vessel size, and available compression---most people don't have a Davey MC2A in their back yard capable of pumping up air cylinders to 2400psig. But I do know of a surplus Bauer that can do 3600psig if anybody is interested...just buy good tanks!

 

As for the 'Air Car'---that's a joint venture with Atlas Copco, the largest Air Compressor Manufacturer in the world (regardless of what the boys in Davidson NC want to tell you...) Atlas Copco was the company which provided the Pneumatic Utility pressure in Paris back in the day. You know? Where they ran pneumatic clocks before electricity was in common usage.

 

The more you learn, the more you forget! Air power was once as common in Paris as Electricity is today. In fact, the name Atlas Copco is a derivation of Atlas Compagnie Pneumatique Compression. There were guys who worked there for over 25 years in the USA that didn't know that... They have been around as an Air Compressor Company as long as Coors has been making Beer.

 

But I digress...

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OHH, isn't pressurizing the roll cage and monitoring the internal pressure one of the ways to check for structural integrity? Wasn't there a manufacturer that used a compress gas charge in their space-frame for this purpose? (Concept being any drop in pressure from the factory charged pressure indicated a latent failure which needed to be found.)

Edited by Tony D
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Wasn't there a manufacturer that used a compress gas charge in their space-frame for this purpose? (Concept being any drop in pressure from the factory charged pressure indicated a latent failure which needed to be found.)

 

Remember the de Havilland Comet?

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It works upon the same general principle as a steam eductor. If you have ever been on jobsites with Coppus Air Coolers this is a high pressure converted to low-pressure high-flow device. They are used extensively in industrial plants to cool machinery or personnel. A small 12 or 17mm hose feeds a larger annulus that induces ambient air and mixes with it using JT-Effect Cooling to drop the ambient temperature and deliver low-pressure high volume air out it's delivery end. Maybe 8 bar goes to the device, at X SCFM, but it produces 40X the SCFM at 1 psi or lower, at maybe 20C lower temperature than ambient air inducted for the amplification!

 

For the Demand Expander Theory, look here:

Demand Expander White Paper

 

This is how an Eductor Works:

Sorry, Wikipedia Link

 

This is the Device most popular for the automotive application, the Air Amplifier:

Air Amplifier Sales Propaganda Link

 

How the Air Amplifier Works:

Neat Animation Link

 

How consumption and usage is dictated:

Consumption Link

 

Now, that link directly above shows a 1:152 amplification ratio, and that shows that if you have 120psi and can deliver it fast enough, you can with 6 scfm flow make well more air than a 3 liter can consume. The limit on this amplifier is that it can't have more than 2" restriction on the downstream side. There are other amplifiers which don't have this restriction, but knowing the effects of 'ram air' and what 2" of WC Positive pressure can have on torque even that little bit can show some interesting bumps in performance for short-term gains. The smaller the engine the easier these become to employ as storage capacity can be lower. ALSO note that not only does this produce positive pressure, it COOLS the intake charge. While an N/A application can make small gains, using one of these to pre-charge a turbo at 2" WC and radically dropped inlet temperature conditions can really make a difference in turbocharger efficiency, but I digress....

 

To take it further, though, an air booster from Bimba isn't practical for this application, but it is a neat little device for someone needing line boost at point-of-use in an industrial setting:

Bimba Air Booster

 

I will agree with Ron's statement that the original schematic as drawn wouldn't result in any boosting. But some quick-dump solenoids and proper amplification and the general principle does have practical application. I would liken it to me drawing some cavement throwing lumps of uranium ore at a larger pile of ore. No, nothing will happen except cancer...but refined a bit and it makes a "BOOM!" ;)

 

Lastly, and finally, here is a link to the Coppus Venturi Coolers---these things are lifesavers in the tropics or in a steam plant---copius (!) ammounts of cool air come out of these, they have amplification ratios that are outrageous and I know for a fact they will build pressure if restricted---enough to shoot basketballs some distance if you do it right! Or golf balls in the suction end... Generally they give around 9" W.C. static blocked-tight discharge pressures, but like anything with the proper eductor design, sized properly for the flow you expect to make, static pressures can be considerably higher with some loss of amplification. These things are at something like 40:1 and are made to flow, not necessarily pressurize. Drop those numbers by 1/4 and you realize your static pressure should increase by a factor of four, minimum.

Coppus Cooler Link

Edited by Tony D
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  • 2 years later...

Necroposted again!

In the interposing 2 years, if anybody is still dubious on how you make airflow without an impeller, I direct you to your local DYSON distributor, and take a look at their bladeless fans (one freestanding unit of which I have just ordered for my house from the United Airlines Mileage Plus Premium Catalog).... The Dyson uses a small higher pressure compressor and the air-amplification mechanics described above to impell COOLER air in the same manner as a fan---without the noise. They're pretty neat, and I would never BUY one...but getting such an opulent sign of consumerist decadance for merely sitting on my arse in a tin tube 5 miles high....or spending money on a credit card appeals to some recessive Scottish Gene in me somewhere!

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