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Two Tiny Gas Turbines

kdawson posted more than 7 years ago | from the burn-a-hole-in-your-pocket dept.

202

Turbines are in the news this morning. bobtheimpossible writes to point out a BBC article on a Swiss turbine that runs at half a million RPM and generates 100 watts. It's the size of a matchbook. And af_robot alerts us to an even more diminuitive gas turbine on a chip, developed at MIT, that generates 10 watts — plenty for portable electronics — and should run 10 times as long as a battery of comparable weight and cost. A commercial version is 3 to 5 years away.

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Still Mechanical Conversion to Energy (4, Insightful)

ackthpt (218170) | more than 7 years ago | (#16279493)

It's still a mecanical conversion of a compounds to energy, with all the inefficiencies that go with it, including disposal of waste heat. Where's these fuel cells I keep hearing about?

10 props for neat, anyway.

also, can it do this? [asciimation.co.nz]

Re:Still Mechanical Conversion to Energy (4, Funny)

bogie (31020) | more than 7 years ago | (#16279589)

"Where's these fuel cells I keep hearing about?"

Why "A commercial version is 3 to 5 years away" of course...

Re:Still Mechanical Conversion to Energy (2)

God'sDuck (837829) | more than 7 years ago | (#16280087)

"A commercial version is 3 to 5 years away"
Remember: 3 years = 1 of work, 1 of stalling, 1 of resume writing. If you're especially good at stalling or especially bad at resume writing, estimate 5.

Re:Still Mechanical Conversion to Energy (1)

HaeMaker (221642) | more than 7 years ago | (#16279619)

Fuel cells are still very hot (at least in the reformation process).

Not only the heat, but am I going to have to get my notebook smogged?

Re:Still Mechanical Conversion to Energy (4, Funny)

roseblood (631824) | more than 7 years ago | (#16280359)

Fuel cells are still very hot (at least in the reformation process).

Not only the heat, but am I going to have to get my notebook smogged?


Just don't let SONY make these. They will have a rootkit and burst into flames, even when turned off.

Inefficiencies? (1)

the_REAL_sam (670858) | more than 7 years ago | (#16279647)

I hate to say it, but RT*A. It says the device is 95% efficient.

"...The matchbox-sized motor generates the equivalent of 100 watts..." "...and has an efficiency of close to 95 percent..."

Re:Inefficiencies? (1)

ackthpt (218170) | more than 7 years ago | (#16279763)

I hate to say it, but RT*A. It says the device is 95% efficient.

I hate that you had to say that after I already had. What's 5% of 100 watts? Plus you've got the exhaust and what do you do when this little bugger wears out? At 1/2 million RPM I don't think you'll be jogging around with it, either as the gyro effect would be a bit tough on it. These are neat, but still, I don't think they're better than an emergency measure.

Re:Inefficiencies? (4, Informative)

jandrese (485) | more than 7 years ago | (#16279993)

What's 5% of 100 watts?
Um, about 5 watts? That's pretty low heat dissipation all told. Exaust and mechanical stress are definatly a concern though, although with components that small at least the masses will be tiny, even if the RPM is exceedingly high. I wonder about the sound though, is it going to drive dogs insane everytime you turn on your Laptop?

Re:Inefficiencies? (1)

ackthpt (218170) | more than 7 years ago | (#16280173)

Um, about 5 watts? That's pretty low heat dissipation all told. Exaust and mechanical stress are definatly a concern though, although with components that small at least the masses will be tiny, even if the RPM is exceedingly high. I wonder about the sound though, is it going to drive dogs insane everytime you turn on your Laptop?

Sounds more like you may encounter some sort of RFI. With a turbo-charger in an auto, you don't use it right away at max RPM but have a warm up and warm down period (those who have gone through a lot of turbos in a short time probably haven't learned this yet.)

Re:Inefficiencies? (1)

Fordiman (689627) | more than 7 years ago | (#16280013)

"What's 5% of 100 watts?"

5 Watts, which isn't a lot of heat to remove.

Still, I'd think about using it as a power source for vehicles, if I believed they could scale it from 100W to about 125kW. (125kW, given 80% motor efficiency, is about the right amount to get 0-60 in about ten seconds given a load of 1 tonne or 1,000 kg. It's an engineering magic number, so far as I'm concerned).

Re:Inefficiencies? (4, Informative)

Colin Smith (2679) | more than 7 years ago | (#16279899)

Sorry, but bollocks it is. A gas turbine is a heat engine, the efficiency is determined by difference between the temperature at combustion and the exhaust gases. 50% would be excellent for a gas turbine.

 

Re:Inefficiencies? (1)

John Hasler (414242) | more than 7 years ago | (#16280569)

The BBC article is about a _generator_, not a turbine. 95% is quite reasonable for a small generator.

Re:Inefficiencies? (1)

Moofie (22272) | more than 7 years ago | (#16280671)

Generators can be powered by gas turbines. As the parent poster said, gas turbine efficiency is related to intake and exhaust temperatures, and 95% efficiency is pretty unrealistic.

Now, efficiency is one of those numbers that people play fast and loose with, so who knows what they actually mean...

6000C combustion? (3, Informative)

Overzeetop (214511) | more than 7 years ago | (#16279931)

That's what it would take for a carnot cycle to be 95% efficient (give or take) with a room temperature heat sink. Is it really burning this hot, or is the article full of shit? (or is my thermo just that rusty?)

Re:6000C combustion? (1)

Fordiman (689627) | more than 7 years ago | (#16280153)

I'd say so. With such a tiny combustion chamber, it's entirely possible that the system can be at 6000C without problem. It's like the reason you don't get burned from an inch away from a cigarette butt; it's freakin' hot, but there's not enough thermal mass to heat much.

Re:6000C combustion? (1)

amorsen (7485) | more than 7 years ago | (#16280967)

With such a tiny combustion chamber, it's entirely possible that the system can be at 6000C without problem.

Which materials do you propose lining the combustion chamber with?

Re:6000C combustion? (1)

billstewart (78916) | more than 7 years ago | (#16281269)

The glass beads we trade to the natives are getting ever more shiny

At 6000 degrees? I'd certainly expect them to be shiny, if they haven't evaporated altogether :-)

Re:6000C combustion? (1)

syphax (189065) | more than 7 years ago | (#16280181)

I just posted the same. Most likely answer: Journalist heard 95% (probably efficiency for some part of the system, likely the electronics), wrote 95%. Alternatively, both of our memories of thermo suck.

Re:6000C combustion? (2, Insightful)

WARM3CH (662028) | more than 7 years ago | (#16280197)

This is a gas turbine: flow of gas turns the rotor. The similar thing that is used in dams to generate electricity. It is not a machine that burns the gas so it is has nothing to do with carnot cycle.

Re:6000C combustion give me a break (1)

radl33t (900691) | more than 7 years ago | (#16281121)

It combusts the fuel with air to form the products that expand through the turbine. Yes it is certainly subject to Carnot limits and it is not 95% thermally efficient. There are no materials that can do 6000 deg C. (For reference this is the temp at the surface of the sun...) This is absurd. The 95% number is clueless.

Re:6000C combustion? (3, Insightful)

John Hasler (414242) | more than 7 years ago | (#16281155)

A gas turbine is a heat engine and is limited by Carnot efficiency. However, the machine described as being 95% efficient in the BBC article is not a gas turbine. It's a generator.

Re:6000C combustion? (0)

Anonymous Coward | more than 7 years ago | (#16281193)

Very nice. But shouldn't the gas be accelerated somehow before it hits the rotor? Carnot cycle gives here maximum theoretical efficiency of heat transformation into kinetic energy of the gas.

Re:6000C combustion? (3, Informative)

Overzeetop (214511) | more than 7 years ago | (#16281321)

That's true, but my (poor) memory seems to recall that no thermodynamic cycle can exceed the Carnot efficiency - it is the theoretical limit. A turbine does have a cycle, though I can't remember the name offhand - it's been almost two decades, and I don't do any thermo in my line of work. ...Okay, google is my friend. The answer is the Brayton cycle, and the effeciency appears to be 1-T1/T2, which is identical to the effiency of the Carnot cycle, presuming theoretical gasses and adiabatic conditions (neither of which exist in turbines). So the answer is still about 6000 Kelvin (not celcius, and extra , which is a good bit above the melting point of most materials. From Wikipaedia: The chemical element with the highest melting point is tungsten, at 3695 K (3422 C, 6192 F). The often-cited carbon does not melt at ambient pressure but sublimates at about 4000 K; a liquid phase only exists above pressures of 10 MPa and estimated 4300-4700 K. Tantalum hafnium carbide (Ta4HfC5) is a refractory compound with a very high melting point of 4488 K (4215 C, 7619 F) I'm banking that this isn't running at 6000K.

Re:6000C combustion? (1)

DieByWire (744043) | more than 7 years ago | (#16281381)

This is a gas turbine: flow of gas turns the rotor.

Correct.

The similar thing that is used in dams to generate electricity. It is not a machine that burns the gas so it is has nothing to do with carnot cycle.

This is a fuel burner - there may be some confusion as to where they're claiming 95% efficiency.

A dam converts potential energy into electricity without combustion, hence it's high efficiency. The article is about a machine that burns fuel - that's where the flow of gas that turns the turbine comes from.

Turbine engine engine efficiency is most definitely connected to compression and combustion temps. That's *one* of the main reasons todays jet ( i.e., turbine) engines are so much more efficient than older engines - better turbine materials can withstand higher temps.

If they're claiming 95% efficiency, they must be referring to only the power out of the turbine versus the power into the turbine section. I don't remember any of the formulas for turbine engine efficiency, but the entire cycle efficiency is absolutely a function of compression and combustion temp. One of the big balancing acts in jet engine design is upping the compression ratio without having the high pressure escape out the front of the engine, which is a 'compressor stall' - a jet engine version of a backfire.

Re:Inefficiencies? (2, Informative)

syphax (189065) | more than 7 years ago | (#16280139)

RTF Textbook [wikipedia.org] Unless I'm missing something, this turbine is a heat engine, just like any other turbine. Heat engines' max. efficiency is 1 - T(cold)/T(hot), where T = absolute temperature (Kelvin or Rankine). At T(cold) is likely room temp (~300K), if this thing is 95% efficient, T(hot) must be around 6000K. That's... hot.

Fuel cells aren't much more efficient (1)

Colin Smith (2679) | more than 7 years ago | (#16279703)

50% if you're lucky, with corresponding 50% heat to get rid of.

 

Re:Still Mechanical Conversion to Energy (1)

Smidge204 (605297) | more than 7 years ago | (#16279751)

These devices are claimed to operate at close to 95% efficiency. Even if that wasn't the case, efficiency doesn't seem like that big a deal when you consider the device of the same size and weight of a battery will provide more than ten times the energy.

=Smidge=

Re:Still Mechanical Conversion to Energy (1)

purpledinoz (573045) | more than 7 years ago | (#16279755)

I wouldn't want this on my laptop, even if it can power it for 10h straight (which would be awesome for the long overseas flights that I have to take on occasion). I would imagine a gas turbine exploding would be worse than exploding lithium batteries.

My turbine asplode! (1)

ackthpt (218170) | more than 7 years ago | (#16279875)

I would imagine a gas turbine exploding would be worse than exploding lithium batteries.

To say nothing of using one of these for dental work, as alluded to in the article. My dentist uses sand, it's a bit annoying, but doesn't rip your face apart with shrapnel if there's a malfunction.

Re:My turbine asplode! (0)

Anonymous Coward | more than 7 years ago | (#16280261)

My dentist uses a laser. The drill is just for coarse shaping work.

Comparason to battery is flawed (1)

EmbeddedJanitor (597831) | more than 7 years ago | (#16279957)

It is all very well saying that this device cranks out more juice than a battery of the same size, but the comparason is a bit flawed.

A battery stores all its fuel + waste products onboard. A turbine needs a bunch of extra peripheral stuff to store its fuel and waste products. Come back when you have a wholse solution.

Re:Still Mechanical Conversion to Energy (1)

Doc Ruby (173196) | more than 7 years ago | (#16280723)

Even the chemical reactions at the center of all these fuel->energy devices are "mechanical". The Swiss turbine is in the cm^3 scale, yet claims 95% efficiency (presumably from the energy content of the fuel delivered to the power of the spinning rotor). Fuelcells operate on catalytic mechanisms for separating electrons from molecules, mechanics at the nanoscale. But the highest fuelcell efficiency I've seen claimed is only about 60%, from fuel to DC current. I wonder what kind of efficiency could be gained from manufacturing the Swiss motor from MEMS. And whether IBM's fast-rotating molecular arrays could be harnessed for even more efficient "fuelcells" at the nanoscale.

While 95->99.999% efficiency might seem a small gain for so much R&D investment, consider that the Swiss turbine has to lose efficiency generating DC to compare with the fuelcells. And consider how much energy could be saved by reducing the waste in vast arrays consuming lots of fuel across the world, from industrial to mobile to micromedical.

Warning (2, Interesting)

Supersonic1425 (903823) | more than 7 years ago | (#16279517)

Do not shake.

Actuallly should be pretty tough (2, Interesting)

wsanders (114993) | more than 7 years ago | (#16279587)

If the trend is anything like hard disk drives, the device should get tougher as the dimensions get smaller.

I'd hate to see one of these things throw off a blade while it's powering your iPod on the subway, though.

Re:Warning (2, Informative)

Anonymous Coward | more than 7 years ago | (#16279665)

You would have a hard time shaking it as the 500,000rpm turbine would act like a Gyroscope.
I would worry about dust, sand, bugs and other small bits getting pass the air inet.

http://en.wikipedia.org/wiki/Gyroscope [wikipedia.org]

gyroscope? (2, Interesting)

Burlap (615181) | more than 7 years ago | (#16279563)

at half a million RPMs, what kind of damage would happen to this thing if it was put in, say, an MP3 player for a jogger?

Re:gyroscope? (1)

Overzeetop (214511) | more than 7 years ago | (#16279633)

Or, more interestingly, how much resistance will you get when trying to rotate it cross-axis.

Also, at 500k rpm, what kind of damage will it do if/when it fails.

Re:gyroscope? (1)

Andrewkov (140579) | more than 7 years ago | (#16281067)

Also, at 500k rpm, what kind of damage will it do if/when it fails.

That's what I was thinking .. Having that in your front pocket when it shreds the casing and escapes could cause serious personal damage.

Re:gyroscope? (4, Funny)

BoberFett (127537) | more than 7 years ago | (#16279651)

Imagine how tough it will be to bend over and tie your shoe with that thing on your hip. That could be a workout on it's own: The Gyroscopic Abdominzeratertron.

Re:gyroscope? (0)

Anonymous Coward | more than 7 years ago | (#16280085)

But imagine how cool it will be when a dog tries to chase you and you open the exhaust port of your iPod and jet pack up into the clouds to safety.

That would easily offset the shoe typing problem.

Re:gyroscope? (4, Insightful)

necro81 (917438) | more than 7 years ago | (#16279895)

Probably not very much. In the picture, you can see the rotor is about the size of a match and probably weighs less than a gram. This means that its moment of inertia isn't all that large (moment of inertia goes like radius squared, in this case, r is on the order of 10^-3 m). Even at 500,000 rpm, the amount of kinetic energy stored in the rotor probably isn't large enough to be a major concern. The relative bulk of the stator probably would be enough to contain it, should it catastrophically fail.

The same is true of the gyroscopic motion - the reactive force is a function of the applied force and the angular momentum. If the moment of inertia of the rotor is very small, the reactant force is likewise small.

Also keep in mind that this device has a designed power output of 100 W, which is at least one, if not two, orders of magnitude greater than what you'd need for an mp3 player.

Re:gyroscope? (1)

TubeSteak (669689) | more than 7 years ago | (#16280287)

Also keep in mind that this device has a designed power output of 100 W, which is at least one, if not two, orders of magnitude greater than what you'd need for an mp3 player.
So how many Amps does it put out?

Can I use one to power an electric motor in a remote control vehicle?
Or to charge a super capacitor in a remote control vehicle?

Re:gyroscope? (1)

Krystlih (543841) | more than 7 years ago | (#16280691)

Isnt that redudant, using an gasoline turbine to power an electric motor? I mean you're converting Gas into electricity via the turbine, then converting the electricity into kinetic energy via the electric engine. Wouldnt it be more efficent to have a gas motor power the remote control vechicle?

Re:gyroscope? (0)

Anonymous Coward | more than 7 years ago | (#16281151)

'bout 8 and a third amps, assuming a 12 volt laptop power supply.

Re:gyroscope? (1)

mspohr (589790) | more than 7 years ago | (#16281289)

voltage * current = watts

Your questions really relate to power (watts), and amperage only one aspect of power.

Dupe with no more info (4, Interesting)

ryanov (193048) | more than 7 years ago | (#16279577)

Two postings now and the obvious question is still not answered... where the hell are you supposed to get the fuel for these things? How are they supposed to be refilled? Still nothing.

Not the first portable gas devices! (3, Insightful)

MadRocketScientist (792254) | more than 7 years ago | (#16279675)

Refillable butane lighters have been around for quite a while, I'd imagine this technology would have a similar refueling mechanism.

Re:Dupe with no more info (1)

dheltzel (558802) | more than 7 years ago | (#16279811)

where the hell are you supposed to get the fuel for these things?

They are gas turbines, silly, eat a bean burrito and you're golden!!

"Cluster"? (1)

bigattichouse (527527) | more than 7 years ago | (#16279597)

Not to play up to the running "beowulf cluster" gag... but could you use a slew of these to run your house?.. backup gen with 10 or 20 of these?

Re:"Cluster"? (1)

Overzeetop (214511) | more than 7 years ago | (#16279869)

Try 100 or 200 for a house with low power demand and a segregated backup panel for limited circuits. I'd need 960 of these to fully backup my house (all electric). Heck, you need twenty just to fire up the old lady's hair drier.

Re:"Cluster"? (1)

JazzyJ (1995) | more than 7 years ago | (#16279955)

Personally I'd be far more worried about the exhaust fumes and whether or not I'd still be alive to enjoy the electricity they are providing.

Sure would keep ya toasty (and probably dead) in the winter tho!

Re:"Cluster"? (1)

Overzeetop (214511) | more than 7 years ago | (#16280001)

No, they just reside outside in their own enclosure, just like anormal backup. A little wart on your house next to the electrical entrance. Of course, I didn't see what either ran on (maybe I missed it) - if it's hydrogen then you're golden, if a little soggy over an extended period. High carbon HCs, then you're not so good.

Power generation (2, Interesting)

harryk (17509) | more than 7 years ago | (#16279611)

I think it's neat that it can output upto 100watts of energy, but at what Amperage and Volt? Could I use a couple of these things to say... act as a battery charger for an electric car?

Re:Power generation (5, Interesting)

Overzeetop (214511) | more than 7 years ago | (#16279807)

At 95% efficiency (a dubious claim, imho, given that the cold sink temp is presumably room temp), it would be a good source for constant charging and potential peaking current. You'd need a good number, though, at roughly 8 to the horsepower.

I think the future might be in portable power and backup devices - having a refillable, continuous 7-15kW power supply in a breadbox. With the right gear ratios, it could put out sinusoidal 60hz power for AC backup, though synchronizing the signals and preventing drift across the array would be a task in itself.

not very relevant (1)

Phantom of the Opera (1867) | more than 7 years ago | (#16279853)

Power is voltage times current (amperage)
    P = I*V
A transformer can alter the voltage (and thus current) to any desired level (of course it cannot up the power).
A transformer is nearly 100% efficient at this.

Re:not very relevant (1)

harryk (17509) | more than 7 years ago | (#16279925)

Perhaps I'm asking the wrong question, but what I'd like to know is could I use a couple of these things to recharge my electric vehicle, or supply enough power to power the electric motor. Probably not, but here's to being hopeful that it could act as a charging system to the say the least.

Re:not very relevant (1)

zippthorne (748122) | more than 7 years ago | (#16280605)

You need to describe your vehicle better. If you've got something roughly the size of mid-size sedan, you'll need somewhere on the order of 30 kWe to operate it. So one 100 We generator could provide enough energy over a full day to operate the vehicle for about five minutes.

On the other hand, if you've got one of those spindly, death-trap solar racers, you get two and a half hours of daily operation from a single generator.

(assuming 100% conversion efficiency all around.)

efficiency of the small (1)

Phantom of the Opera (1867) | more than 7 years ago | (#16280735)

Efficiency can be a function of size in some cases. For example, cyclone separators [wikipedia.org] become far more efficient when small.

If you have a tiny turbine, there is going to be less of an area for air resistence to its turning, for example. Dust would become an issue at that point, though.

The chemistry is a challenge. Complete combustion usually requires a hot enough environment, but for a tiny turbine, it might be sufficient to have a catalyst to achieve good combustion.

The article did not mention the efficiency achieved but 10 wats is tremendous for such a small thing. But to give an idea, gasoline has about 30 MegaJoules per liter. This translates to 30 KJ per ml. That means that a mililiter would power the 10 watt turbine for about 8 hours. To give you an idea, a typical cigarette lighter holds 25 ml.

Re:Power generation (2, Informative)

Lumpy (12016) | more than 7 years ago | (#16280217)

it generates 100 watts. 20 amps at 5 volts. 10 amps at 10 volts 1 amp at 100 volts or .1 amp at 1000 volts.

Take ypur pick, you can generate from 0.001 volts at insane amps or millions of volts at nearly no amps.

Watts are universal and translate to all voltages.. anyone with a very basic background in electricity or electronics knows this.

fill them up? (1)

joe 155 (937621) | more than 7 years ago | (#16279613)

"one tankful of fuel drives the generator for about 10 hours at peak 100 watt performance"

they talk about putting these in mobile phones, but I wonder if they are gas powered how they will be re-filled. I wonder if we will end up in a situation where we have to wait for the gas man to come each morning if we run out

Re:fill them up? (1)

Knuckles (8964) | more than 7 years ago | (#16280601)

That's what you get after stamping out the smokers. Worthwhile locations have shops stocking butane gas refillers for cigarette lighters on every corner.

half a million RPM (0)

Anonymous Coward | more than 7 years ago | (#16279621)

Half a million RPM .. wow sounds fast! Hmm .. but actually .. if we look at the "velocity" .. it's probably not that fast..

Hmm the MIT one .. you can probably stop this thing with your finger .. probably there'll be an angry sharp sting style pain .. but I doubt there'd be a cut (10 watts right? .. what's the potential though).

F=ma

I could be wrong though .. someone run the numbers..

Exhaust? (1)

MankyD (567984) | more than 7 years ago | (#16279623)

Is it safe to use engines like this in enclosed spaces? An airplane is a great example, but even my office with sealed window could be a problem. Anyone have more details? Similarly, it says it can run 10 hours, but how much fuel is that? My car engine could run all year if I left it hooked up to a gas pump.

Re:Exhaust? (1)

imsabbel (611519) | more than 7 years ago | (#16279701)

Dont underestimate the energy of chemical reactions.
With 100W at 95% efficiency, it doesnt output more CO2 than a human breathing.

Re:Exhaust? (1)

MustardMan (52102) | more than 7 years ago | (#16280307)

How exactly does the energetic efficiency automatically tell you something about the amount of CO2 being put out?

Re:Exhaust? (1)

MankyD (567984) | more than 7 years ago | (#16280463)

What he/she is saying is that 100W at 95% efficiency gives you the CO2 output. (95% efficiency would mean ~105.3 Watts worth of chemical energy is required. 1 watt = 1 joule/second.) Whether or not they actually did the math or know what type of fuel is being used is a different story, but it is, in theory, possible to figure it out.

mod 04 (-1, Troll)

Anonymous Coward | more than 7 years ago | (#16279625)

momentum? (1)

Sebastopol (189276) | more than 7 years ago | (#16279629)

so do these things act like gyroscopes? i realize it is a small mass, but a super high rpm generates a big L. hate to have one powering my ipod, i could only jog in a straight line...

Ear plugs? (3, Insightful)

jo42 (227475) | more than 7 years ago | (#16279745)

Will these devices come with ear plugs or noise blocking head phones?

Re:Ear plugs? (1)

neovoxx (818095) | more than 7 years ago | (#16281363)

Any noise generated by these engines would likely be well beyond the human hearing range, negating the need for any sound dampening.  My main concern would be protection from the turbine blades.

Always (1)

eclectro (227083) | more than 7 years ago | (#16279881)

A commercial version is 3 to 5 years away.

Why is is all this stuff always "3 to 5" years away?? Blisterpack these things and get them out to market already.

Reversal of use (3, Interesting)

LParks (927321) | more than 7 years ago | (#16279921)

So our portable energy used to come from batteries, and now its becoming gas-powered. And our large vehicle engines used to all be gas powered, and now it comes from batteries. Interesting reversal.

melting motors? (1)

cmclaren (813300) | more than 7 years ago | (#16279933)

The process begins with a tiny combustion chamber where fuel and air mix and burn at the melting point of steel.

..which is about the same melting point as silicon

Heat? (1)

Zach978 (98911) | more than 7 years ago | (#16279939)

Wouldn't this thing get pretty hot in my pocket?

None have run yet? (2, Interesting)

sidles (735901) | more than 7 years ago | (#16280063)

It takes a lot of reading to realize that none of these sub-centimeter turbines has actually run yet. Perhaps the laws of combustion physics prevent this? There's a reason why candle flames are the size they are ... see Michael Faraday's classic lecture The Chemical History of a Candle [bartleby.com] .

Oblig.. (1)

le0p (932717) | more than 7 years ago | (#16280071)

Imagine a Beowulf clust..I think you know the rest.

Material fatigue? (2, Interesting)

qwertphobia (825473) | more than 7 years ago | (#16280077)

What happens after one of these has been used off and on for a few years and the materials start to fatigue? Have we all seen the videos of the CD-Roms spun on a Dremmel tool until they explode? Hint: convert 500k (or 1M) rpms into linear velocity at the outside radius of the turbine.

Re:Material fatigue? (1)

Cthefuture (665326) | more than 7 years ago | (#16280297)

Well lets see:

Assuming a 5 mm diameter (could be slightly larger or smaller, I dunno) at 500k RPM that's about 4.6 MPH on the outside. Also consider the parts would have very little mass and could probably be blocked with nothing more than a thin sheet of aluminum.

ie. less than 5 MPH, no real risk there unless maybe a tiny bit of metal went in your eye but as I said this should be trival to shield.

Of course my math might be wrong as I'm in a hurry, please double check me.

Re:Material fatigue? (1)

JesseL (107722) | more than 7 years ago | (#16280665)

Assuming this has a 20mm diameter turbine, at 500KRPM it will have an angular velocity of 130 meters/second at the outside edge. While this is enough velocity to put your eye out if it was too close to a turbine disintegration, it would be trivially easy to make a suitable scatter shield.

Uncontained turbine failure = bad Ju Ju (1)

russ1337 (938915) | more than 7 years ago | (#16280167)

Ever seen the results of an uncontained turbine failure on a jet engine? Just make it 100 times smaller 10 times faster and in your pocket.

Re:Uncontained turbine failure = bad Ju Ju (1)

Knuckles (8964) | more than 7 years ago | (#16280703)

Take an elephant make it 100 times smaller and you've got a rabbit?

Re:Uncontained turbine failure = bad Ju Ju (1)

shis-ka-bob (595298) | more than 7 years ago | (#16280707)

I did see the results of a turbo pump failure & heard about the results of a time of flight chopper failure. These were blades of 10s of centimeters. They were considerably larger than the turbines being described, but both were potentially lethal. I also saw a much smaller pump fail & it made a bang & turned the insides blades into scrap metal but didn't do anything dangerous. The amount of kinetic energy is proportional to product of the mass and the the square of the radius, so little turbines become a lot safer than big turbines. All of these turbines are probably designed to run about as fast as material strength will allow, so overdriving them can be catastrophic. (e.g., the blade flies appart.) But if these are sub centimeter and in descently heavy containers, they ought to be safe. I just don't have any intution about the needed shielding & if I want to carry that in my pocket.

Re:Uncontained turbine failure = bad Ju Ju (1)

nixkuroi (569546) | more than 7 years ago | (#16281023)

"Ever seen the results of an uncontained turbine failure on a jet engine? Just make it 100 times smaller 10 times faster and in your pocket."

This gives a whole new spin to the advice ol' grandad gave when he told me to "wear a helmet".

Re:Uncontained turbine failure = bad Ju Ju (2, Interesting)

dschuetz (10924) | more than 7 years ago | (#16281143)

Ever seen the results of an uncontained turbine failure on a jet engine?

Have you ever seen the results of a *contained* failure? A while back, as the Boeing 777 was just coming into commercial use, PBS ran a long special (or maybe a series of episodes, I forget) about the plane. They showed how they wrapped the engine in some kind of special kevlar blanket, then tested it by shooting something into a fully spun-up engine.

The outsides of the engine (the whole chamber) sort of bulged out maybe 6-12", then compressed back down to normal size. And that was it. It looked like something out of a cartoon, where (say) Bugs Bunny might swallow a lit stick of dynamite, then his stomach would bulge suddenly as it exploded, then he'd burp out a small puff smoke and be done with it. Really very cool, actually.

Anyway, I'd expect they could do something similar with this, too. Plus, even though it's spinning faster, the mass of the spinning parts is probably pretty infinitessimal, so even a total catastrophic failure at 1 million RPM might not be cause for concern. (as compared to the mass of the fan blades in a massive jet engine).

Would you buy one? (2, Interesting)

bmetz (523) | more than 7 years ago | (#16280299)

I honestly wonder who these are for. I wouldn't use a cell phone or a laptop with a gas turbine in them. The noise, the vibration, the fumes, the refill process; even in the most ideal circumstances I am too spoiled by 'good enough' battery technology.

I'd like to see more work on battery technology and more pervasive conductive surfaces so every place I set my laptop and cell phone down helps charge it.

Re:Would you buy one? (1)

radl33t (900691) | more than 7 years ago | (#16281299)

This just in... batteries suck.

Significantly different technology is required to undue this. Power conversion/storage is a big area of research, why can't multiple solutions be pursued simultaneously? Given the undeveloped state of microturbines, I find it unlikely you are in a position to comment about their operation under 'ideal' circumstances. It is possible right now to build a reciprocating (e.g. piston) engine to power your laptop with no perceptible vibration or sound beyond that of the DC fan in your laptop.

It's Cool... (1)

gyrogeerloose (849181) | more than 7 years ago | (#16280309)

...but I'm still holding out for Mr. Fusion.

Old News..... (1)

IHC Navistar (967161) | more than 7 years ago | (#16280385)

This is old... I'm not sure about being ols SlashDot news, but it is old news in general. I saw programs about this EXACT turbine on the History Channel about 6 years ago.

What people should spend the research dollars on is trying to figure out why people keep recycling old news as 'new' news and figure out how to put that to an end. *THEN* they can proceed with whatever they want.

Not a Turbine (1)

John Hasler (414242) | more than 7 years ago | (#16280449)

The BBC article is about a generator, not a turbine. The article merely mentions in passing that it could be powered by a turbine.

Article close to pure crapola! (4, Informative)

Ancient_Hacker (751168) | more than 7 years ago | (#16280539)

An efficiency of 95% ! ?

The best large gas turbines do about 35%.

And efficiency drops very quickly with size-- you see friction goes down as the square of the size, while power goes down as the cube. Somewhere between the size of a sausage and a hot dog, all the turbine power is going into overcoming friction.

And the biz about 1 million RPM is pure hokum-- the worlds record is a bit below that, and that was with a tungsten alloy rotor in a vacuum chamber.

Methinks some press agent was drinking while on duty.

Re:Article close to pure crapola! (2, Interesting)

Big_Breaker (190457) | more than 7 years ago | (#16281385)

Efficiency is often quoted as a % of Carnot efficiency, which is the efficiency limit for a pure heat engine and it's around 35%-40% depending on temperature. I think turbines are subject to a lower limit which happens to be around 90-95% below Carnot.

Anyway - who cares? Efficiency in small devices is MEANINGLESS. What matters is power and energy density by volume and weight. This has both in spades.

Batteries are incredibly efficient, but you need to generate the power to charge them somehow. They also (generally) have very poor power and energy density by weight and volume. Supercaps are great with power density and some press releases claim enormous increases in energy density but we haven't seen it yet.

These turbines are shrunken versions of proven technology. It seems very credible and promising. At small sizes and high RPM things like air bearings work BETTER. And those RPM records are for large rotating masses. These are tiny and easy to hold together. Translate 500k RPM into a linear m/s measure for a cm diameter turbine and you'll understand better. The edge doesn't even break the sound barrier (though it does approach it).

This is a DARPA spinoff (2, Informative)

Animats (122034) | more than 7 years ago | (#16280543)

DARPA has been funding this kind of thing for years. Small turbines [m-dot.com] have resulted. DARPA was originally trying to develop bird-sized unmanned aerial vehicles. [wikipedia.org] That R&D program produced some flyable devices, but they didn't have the low cost and 2-hour endurance DARPA wanted.

DARPA-funded work at MIT resulted in some microturbine parts [memagazine.org] back in 1997. Progress has been slower than expected, but it's happening.

The microgenerator thing was intended as a military application. The idea is to have something small, maybe even wearable, a soldier can use to recharge all the battery-operated gear. Battery recharging in the field, where power outlets are rare, is getting to be a huge hassle in the US military. Current technology is to put power outlets on everything with wheels and an engine, but that creates its own headaches.

Not for laptops (2, Funny)

Shotgun (30919) | more than 7 years ago | (#16280555)

New battery? Must be for laptops!!

'Cmon? Does everything have to be "a new way to power your laptop"? First, who the hell wants a 500,000 RPM anything sitting in their lap? The high squeal resonant frequencies will be hell once it is about two weeks old. I'll pass, and I'll ask the stewardess to shut down the guy trying to use one next to me. Second, what happens when the enterprize standardizes on this thing, and you have a cubicle farm of laptops spew CO2 (and a small component of CO) into the closed office atmosphere. I'll pass, and I'll use the Worker's Compensation claim to its max if I survive the asphixiation.

The guy says that he was surprised that designing the combustion chamber turned out to be easy, but the bearings were hard. He expected it to be the other way around. Well, no shit, Sherlock? Stationary components are easy and moving parts are hard. That applies to all mechanical systems. Duh? Someone else justified the high RPM in a previous post, noting how small the rotor will be. The gyroscopic forces trying to pull the laptop from your hands when the taxi rounds the corner will indeed be small, but the forces on the rotor bearings in relation to their size will be huge. The laptop may not rip from your hands, but it will get quiet (which the taxi driver will appreciate).

How about putting one of these in a container the size of a breadbox, and mounting it above a septic tank in a small village or country farm. Have it charge a battery as it feeds off the methane produced?

Re:Not for laptops (1)

object88 (568048) | more than 7 years ago | (#16281341)

First, who the hell wants a 500,000 RPM anything sitting in their lap? The high squeal resonant frequencies will be hell once it is about two weeks old.

I don't know a lot about resonant frequencies, but I can't imagine that you'll end up with many audible frequencies in the range of human hearing from a turbine running at 500kHz. CRT monitors used to squeel at a very high pitch-- let's say 10kHz just for the sake of argument-- and they were running at ~80kHz refresh rates? Where's that put the squeel of a device running at 6.25 times the frequency?

one more reason (1)

c0reboarder (885528) | more than 7 years ago | (#16280689)

yay, one more reason to burn oil... awesome!

See this test platform (1)

afternoon_nap (640340) | more than 7 years ago | (#16280765)

I think this was an original test platform for the smaller turbine: see here [hamsexy.com] .

10 watts -- plenty for portable electronics? (1)

constantnormal (512494) | more than 7 years ago | (#16280983)

I guess that "portable electronics" does not include notebook computers. I see that the power brick for my G4 iBook provides 65W and the power adapter for the new MacBook Pro provides 85W.

And I can't wait to read the headlines of the first bunch of software developers, found dead from carbon monoxide posoning after a long weekend of burning the midnight oil (or kerosene, butame or propane). Personal oxygen supplies may become the next big thing in office equipment.

Does it twist your arm? (2, Interesting)

cohomology (111648) | more than 7 years ago | (#16281291)

The rotor of the Swiss turbine must be pretty beefy. How much angular momentum does it have at 500,000 RPM? If you've ever played with a large gyroscope, or twirled a bicycle wheel while holding onto its axle, you can see the problem. If you try to change the direction of its angular momentum vector, the thing will twist around an axis perpendicular to both its angular momentum vector, and the direction of the torque you apply. If this thing is in a laptop, spinning around an axis parallel to the floor, and you walk around a corner, the laptop could flip in a very surprising way.

Go45t (-1, Offtopic)

Anonymous Coward | more than 7 years ago | (#16281377)

[gay-sex-accees.com]? code.' Don't my resignation and the bottom
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