Dysons latest thinking - Fanless cooling??

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gotwind

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Post Thu Jan 01, 1970 1:00 am

The famed U.K. product designer James Dyson and h

The famed U.K. product designer James Dyson and his massive R&D team are very smart for sure, oddly Im not a great fan of the Dyson range of vacumn cleaners, they never seem to work that well for me, they suck - badly
Interesting to know other peoples experiences.



This latest fanless fan idea, the Air Multiplierâ„¢ , press released today may have some merit in the wind industry, maybe not - A very clever idea though, and looks cool.
http://www.dyson.co.uk/fans/

How it works here
http://www.dyson.co.uk/technology/airmultiplier.asp

Ben.
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DENNIS A

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Post Thu Jan 01, 1970 1:00 am

Hi Ben

Is there not an electric fan t

Hi Ben

Is there not an electric fan to draw the air into the square cut outs of the base section.

Dennis
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tecon

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Post Thu Jan 01, 1970 1:00 am

I read that too Dennis, "drawn in by an energy-ef

I read that too Dennis, "drawn in by an energy-efficient, brushless motor".

I guess from there they are just feeding the air through ports to stablize/even the flow and eliminate blades?

It would in theory create a slight vacum effect, although I am guessing the percentage of the effect would be quite small to miniscule?

Tim
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daveames

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Post Thu Jan 01, 1970 1:00 am


sounds like a dream job there. imagine hav


sounds like a dream job there. imagine having state of the art facilities and almost unlimited funding where one could go to work and play all day!

yes, a clever bunch dyson has put together. ive had one of his ball vacummes apart (yes and back together again) very well made machine.

the idea here with the "air multiplier" seems to be that we can bring a small volume of air up to a higher speed then feed it through openings in this circular air horn and mix with the surrounding air for a steady low speed higher volume breeze. all sounds very well thought out.

i saw/heard somewhere that his r&d team is filing an average of a patent a day!

cheers, dave
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DENNIS A

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Post Thu Jan 01, 1970 1:00 am

Dave
The fan air would be discharged through

Dave
The fan air would be discharged through a fine slot in the ring then follow the shape and draw in the additional air. This is working on the Coanda principle which has been around for about 100 years and came to light on one of the first rocket planes. This type of air mover has in the past been used with high pressue air or steam. Dyson could not patent the princible only the construction or application.

Dennis
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gotwind

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Post Thu Jan 01, 1970 1:00 am

An interesting insight there Dennis.

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daveames

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Post Thu Jan 01, 1970 1:00 am

dennis/ben,

thanks for that info and

dennis/ben,

thanks for that info and link. sure makes for an interesting read. that proves some of these "old" ideas still have not been explored to their full potential. cool.

thanks, dave
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Fish4Fun

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Post Thu Jan 01, 1970 1:00 am

It took me a little longer than most to figure ou

It took me a little longer than most to figure out exactly what this fan was doing; but once I finally "got it", I was intrigued, if not a bit skeptical, by the idea. I own a Dyson vacuum cleaner, and while it is not "magic", it is very well engineered; so, I really looked forward to having a bit of time to ponder the claims. Basically what we have in the Dyson fan would appear to be a very conventional fan that is carefully designed to be coupled with its surrounding environment in a way that magnifies the effect one might expect from the otherwise fairly ordinary fan. But it is important to note that this is engineering and not some fundamental departure from the laws of physics. Following is a brief mathematical explanation of how this might be achieved.

As mentioned, the Coanda and the venturi effect lie at the heart of the Dyson design. These effects rely on a high velocity stream to "entrain" or mix with a lower velocity stream in a similar direction. The only real distinguishing factor between the effects used in Dysons fan design and a conventional fan are the efficiency and evenness of the flow.

If we assume that the power in the air stream produced by the fan is:

P = C * A * V^3

Where C is the product of the various constants, A is the swept area of the fan and V is the velocity of the air stream, then it is fairly trivial to re-write this as follows:

Po ~ Pi => C * A1 * V1^3 = C * A2 * V2^3 ==> A1 * V1^3 = A2 * V2^3

That is simply to say, as the area of the wind stream increases, the velocity of the wind stream decreases proportionally. This general notion holds for both a conventional fan and Dysons design; what separates the two models is the efficiency with which this proportionality is maintained. Now, Dysons claim of a 15X increase in the wind stream volume is problematic in that there is no clarification about WHERE this increase is measured. But lets leave that alone for a moment and focus on what a 15X increase in air volume means from a velocity point-of-view. Assuming there are no losses associate with the Dyson process, and that an "increased volume of 15X" really means "15X the Area"

A1 * V1^3 = (15 * A1) * V2^3 ==> 15 = (V1/V2)^3 => V1/V2 = 2.466

That is, V1 would be 2.466 times that of V2. This calculation obviously leaves a lot of real-world factors out, and the assumption that "15X Volume = 15X Area" is dubious at best, but the notion that a 15X increase in volume could be achieved with a fairly small decrease in stream velocity is demonstrated, lending credence to the theory behind Dysons fan.

It is a very interesting concept, and would certainly make an interesting conversation piece, but the price tag is pretty steep if one is simply looking to move a bit of warm air around a room. I would be interested to find out if the air stream produced at a specific distance and speed were in fact achieved at a lower electrical power input than a conventional fan, but I suspect making a meaningful comparison would be extremely difficult.

Fish

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Gotwind Ben

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Post Sat Jun 26, 2010 6:26 pm

Re: Dysons latest thinking - Fanless cooling??

Old post, but maybe worth bringing up.
I saw one of these in action today, it worked very well, similar in power to a bladed variety of similar diameter, quite an odd sight really.
After a glass of red wine :P
I wonder if this could be reversed to create power from such a design :?:

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