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Jet Engine on a Chip
Roland Piquepaille writes "Today, our handheld devices are powered by batteries, which are heavy and inconvenient. Fuel cells are just arriving on the market as a replacement. But there is a new contender: micro gas turbine engines under development at the MIT. Engineers there shrunk jet engines to the size of a coat button. And their blades which span an area smaller than a dime can spin a million times per minute and produce enough electricity to power your PDA or your cell phone. While there are still a few hurdles to overcome, these micro turbine engines should be operational in two or three years, with commercial products available four years from now. These micro jet engines also have the potential to free soldiers or travelers from carrying heavy batteries. The engineers even think their engines on a chip could be used in poor countries to bring electricity there. This summary gives you the essential details about a technology which promises to free us to carry extra fuel instead of batteries."
Engineers there shrunk jet engines to the size of a coat button
Naturally the Department of Homeland Security will declare that people with 4 or more buttons on their coat are 'terrorists'
Trolling is a art,
1. That's pretty damned cool. Gas Turbines are some of the most efficient fuel -> energy converters known to man.
2. Saying that a Gas Turbine == a Jet Engine is a bit misleading. It's a bit like saying "Scientists have shrunk an electric motor to 4 nanmometers", then before you even finish thinking about all the MEMS devices, you read "Scientists have produced a 4 nanometer electric genertor for use in making power for MEMS devices." Still very cool, but not the same thing.
Javascript + Nintendo DSi = DSiCade
What about the exaust?
I can't wait to get kicked out of a snooty coffee shop because my dual core G5 laptop was asphyxiating the customers . . .
Fantastic! Glad to see a post by you Roland! You see, I really enjoy absolute shit, so I am glad to see another of your presumably bought and paid for fluff stories.
I used to bulls-eye womp-rats in my pants
http://science.slashdot.org/search.pl?query=Rolan
How many years now have we been hearing about miniature turbine power sources? Too many. Just because some kids at MIT did it doesn't mean it's even close to being commercially viable, and even if it is viable doesn't mean anybody will adopt it. That aside, I do think it's a great concept and I hope it DOES eventually get adopted, especially if they can make the turbines run on vegetable oil :)
-73, de n1ywb
www.n1ywb.com
While there are still a few hurdles to overcome...
Ya think?
Yeah? Well I think you're overrated too.
If the fuel is a clean hydrocarbon, the exhaust will be CO2 and H2O. Using batteries pollutes too, you just don't see it right there because it's either at the power plant where your battery charger got it's energy from, or it's in the chemical pollution of used dead batteries, or both.
This is exactly true. Roland Piquepaille submits fluff stories to /. over and over and over just to generate traffic to his blog. Slashdot ... come on. You can do better.
KARMA TAG! You're it.
There was a bit of calculator one-up-manship in some of my classes, so I always wanted to connect a little model airplane engine to a little generator and use it to power my calculator during exams. Besides the roar of the non-mufflered engine (dropping in RPMs during every keypress as it consumes more power), there would be the smell half-burnt gas coming out of that little two-stroke. The intimidation factor alone would have skewed the curve in my direction.
So, wow, my silly dreams could become reality!
HIV Crosses Species Barrier... into Muppets
I read somewhere that farting releases methane. May be these micro-jet engines can be powered by far gas. On an airplane, the PDA can be inserted in a pocket on the seat and just a fart will power the PDA micro-jet ;-)
TSA Drone: "What do you have in that bottle?"
You: "Oh, it's just some gasoline for my laptop."
Sure...this technology will be a GREAT laptop power source for travelers...
Do these things still make a horrid mess when they accidentally suck geese in through the intake?
This matters a lot, because small turbines suffer much more from viscous flow losses and heat-transfer losses than large ones. If a 50 W microturbine is 10% efficient, its waste heat will amount to 450 watts; if it is 5% efficient, the waste heat will be 950 watts! This could easily lead to them being banned from commercial aircraft, because the extra heat load and oxygen consumption would drive A/C loading too high (not to mention the discomfort of adjacent passengers).
Sustainability and energy independence essay
Beats blaming it on the dog I guess... :)
A goal is a dream with a deadline
Compare with traditional rechargable batteries.
First, there is the one-time environmental cost of manufacturing the batteries. Making a battery requires fuel for mining equipment, transporting the materials, running the manufacturing equipment, and producing the electrolyte.
Second, there is the energy required to charge the battery. This energy comes from the power grid. Ultimately, it comes from burning fossil fuels in power plants. This energy must be transmitted via wires to an electrical outlet, turned into DC by a rectifier, and finally, used to charge the battery.
In other words, here's the energy path for the turbine:
Fossil fuel ---> Combustion ---> Turn turbine ---> Generate DC power
And for the rechargable batteries:
Fossil fuel ---> Combustion ---> Turn turbine ---> Generate AC current ---> Transform to high voltage ---> Transmit down wires ---> Transform back to low voltage ---> Rectify to DC power
Which do you think is more efficient?
"Each disposable cartridge would pack as much energy as a few heavy handfuls of lithium-ion batteries."
We don't really want to carry larger and larger packages of energy on our person. As it is, we are seeing accidents like this one due to today's ordinary lithium-ion batteries. And I recently got a recall notice from Verizon about the kind of batteries used in my cell phone, so this isn't an isolated incident.
When someone tosses a 9V battery in their pocket and it gets shorted out by a coin, they are startled, yell, and pick the hot coin out of their pocket.
When a cell phone battery acts up, Shelley Kaehr got a handful of battery acid and set fire to the floor.
Multiply that by "a few heavy handfuls" and you start to get the possibility of really serious personal injury.
What we need are breakthroughs on the power consumption side, not ever-increasing power supplies
"How to Do Nothing," kids activities, back in print!
"Hey, what is that?"
"WHAT?"
"I said, what is that"
"MY NEW JET-POWERED MP3 PLAYER"
"cool , what are you playing?"
"I'M NOT SURE"
"There is more worth loving than we have strength to love." - Brian Jay Stanley
In all seriousness, why does
Yes, this is probably off-topic (as in "not about tiny turbines") but it is still relevant. At least give us the option to ignore him.
I want to drag this out as long as possible. Bring me my protractor.
Can we please stop posting directly to stories on this guy's weblog? It's embarassing for Slashdot. The real news link you're looking for is:
here
For as much as I love Slashdot, there exists little recourse for people who want their input on the site to be heard, even when its on as large a scale as the current hatred of Roland posts.
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Long-term storage of hydrogen is still a bit of a problem. Hydrogen has a tendency to penetrate ANYTHING you try to store it in, resulting in hydrogen embrittlement. In short, anything you store hydrogen in (esp. pressurized hydrogen) will eventually become weakened by the hydrogen permeating it.
retrorocket.o not found, launch anyway?
Hmmmmm, the last thing I would want to happen, is to go into a restaurant/bar/nightclub with a PDA in my trouser pocket, stand up, and have everyone notice there's a damp patch somewhere personal.
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1. That's pretty damned cool. Gas Turbines are some of the most efficient fuel -> energy converters known to man.
You will also notice that (in general) the smaller the gas turbine, the less efficient.
I have been to multiple talks on these engines, I used to work for one of the industry colaborators on the project as an aerodynamicist. These engines are no exception to that rule. The turbine on these engines hardly extracts enough work to run the compresser when you are running the combuster just below the melting point of the engine.
Also (addressing the summary, not the parent post), these things have been "2-3 years away" for at least 6 years.
"I'll have a Guinness, no wait, make that a Coors Light" -Grad student I work with, who shall remain anonymous...
Well, IAAEE (I am an electrical engineer) and I'm gunna have to say that the turbine is going to have to transform its output voltage somehow anyway. Not that transformers deplete much power at all, but still, it is almost certainly more efficient to use a transformer after the turbine than screwing with the turbine to produce different voltage / frequencies. Also, the tiny turbine is going to have to rectify to dc power also. AC power is the "natural" form of electricity produced by power plants. It always requires an extra step to get dc. Finally, there is an economy of scale involved. A small turbine is simply not going to be as efficient as a large one. I would expect one that small to be nowhere near as efficient as a power plant. I would expect that the difference in efficiency of turbines would more than equal out the benefit of avoiding transformation (which is a very efficient process, for good transformers at least).
The important question is actually, which one weighs more? Which one is cheaper to use? Seriously, who cares about the environmental effects. We have millions and millions of big engines in the form of cars, a few hundred thousand small gas turbines aren't going to matter much.
I submitted this story last night, and it didn't get posted.
I don't see the rationale for that, as long as they file a flight plan for their coat.
What's top speed for a London Fog?
sigs, as if you care.
A better TR article blasts "hydrogen hype" but in fact H2 would be about the best fuel for these little buzzers:
- a fuel spill will dissapate very rapidly
- the byproduct, in answer to the questions posted re pollution is just water.
A set of bearings however will be an awsome thing to handle the gyroscopic reaction torques as you wave your jet powered cellphone about. You turn the corner, the phone does not. I don't have my old physics books handy but the linear velocity of a point on the tip of a blade isand is changing direction 180 degrees about 2000000 times a minute. The F=MA to pull this constant direction change will be staggering unless M is damn near zero.And aren't you just all breathless, when the "batteries die", to take your cellphone to the out-of-work airline mechanic who got re-trained at a watch factory ?
SLASHDOT: news for people who can't concentrate on work or have no life at all and got tired of yelling back at the TV.
They've been working on this since 1993, and in 1997 they said they'd have it working in three years. In 2004, they say they'll have it working in three years.
It doesn't work yet. They can fabricate the individual parts, but it doesn't really generate power.
It's not an unreasonable idea, but if this was going to work, there should already be little gas turbine powerplants a few inches long, machined out of metal by standard techniques. The smallest turbines available weight around 1.5Kg, and are used for model aircraft, and they don't have to run for very long. There's a "microturbine" industry, but they mean 10KW units taller than a man.
Little turbines are hard. Automotive turbines and light-plane turbines have been attempted many times, but have never been cost-effective.
Sustainability and energy independence essay
Beats blaming it on the dog I guess... :)
A guy goes to dinner with his girlfriend's family, and finds he is a bit windy about the arse. Anyway, he is sitting down at table, and the family dog is lying down behind his chair, so he figures he'll try a little experiment. So, he shifts his weight to his left cheek, and squeezes out a fairly quiet fart.
The mother looks up at the noise, and says "Baron!" (this being the dog's name). Encouraged, the guy lets out another one, quite a bit louder this time.
Again, the mother looks up, and exclaims "Baron!" in a more urgent tone.
By now the guy figures he's got carte blanche for whatever trouser stunts he wants to pull, so he let's rip with all his might, and lets one go that sounds like the curtains are being ripped in half!
At this, the mother stands up, panic-stricken, and shouts "Baron! Get away from that man before he shits all over you!"
Call me old fashioned, but I like a dump to be as memorable as it is devastating - Bender
is that many of the physicists working on the problem don't understand fluid mechanics at such a small scale. The viscous forces are huge compared to the inertial forces, and you have a completely different set of physics.
That's why you don't see very many working concepts of small aircraft (the kind that fit in the palm of your hand) with what most people recognize as wings. They're usually equipped with small flat-plate type wings, or a ribbon-like system like on a cuttlefish.
And the reason that many folks that do happen to understand the physics don't try and do things at such small scales is that the problem is difficult. Not impossible, but difficult.
As a person with a background in fluid mechanics, I don't see how the approach in the article will ever work well or efficiently. It might work, but it's not using the kind of principles that you need. (The whole point of my post is that you can't scale a device down without adjusting or remaking how it does what it does. The physics change.)
Remember, even the worst farts aren't 100% methane
The sun is a mass of incandescent gas... ^H^H oops sorry... wrong comment.
Here's the lowdown on fart gas content, for those interested in such things:
(source: Facts on Farts)
What is fart gas made of?
The composition of fart gas is highly variable.
Most of the air we swallow, especially the oxygen component, is absorbed by the body before the gas gets into the intestines. By the time the air reaches the large intestine, most of what is left is nitrogen. Chemical reactions between stomach acid and intestinal fluids may produce carbon dioxide, which is also a component of air and a product of bacterial action. Bacteria also produce hydrogen and methane.
But the relative proportions of these gases that emerge from our anal opening depend on several factors: what we ate, how much air we swallowed, what kinds of bacteria we have in our intestines, and how long we hold in the fart.
The longer a fart is held in, the larger the proportion of inert nitrogen it contains, because the other gases tend to be absorbed into the bloodstream through the walls of the intestine.
A nervous person who swallows a lot of air and who moves stuff through his digestive system rapidly may have a lot of oxygen in his farts, because his body didn't have time to absorb the oxygen.
According to Dr. James L. A. Roth, the author of Gastrointestinal Gas (Ch. 17 in Gastroenterology, v. 4, 1976) most people (2/3 of adults) pass farts that contain no methane. If both parents are methane producers, their children have a 95% chance of being producers as well. The reason for this is apparently unknown. Some researchers suspect a genetic influence, whereas others think the ability is due to environmental factors. However, all methane in any farts comes from bacterial action and not from human cells.
Damp patch? You're worried about a damp patch??
I'd be more worried about having blades rotating a million times a minute right next to my genitals!