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."

Comments

Cool, but misleading title

[AKAImBatman]

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.

Re:Cool, but misleading title

[kaszeta]

Gas Turbines are some of the most efficient fuel -> energy converters known to man.

Actually, in terms of the overall thermodynamic efficiency, they aren't all that great. 40% efficiency is *very* good for a Brayton cycle (i.e. turbine engine) system, but is fairly easily done with a large-scale steam system. Microturbines tend to run around 25%, which means that (a) you need a fairly big recuperator to run efficiently (which doesn't seem to be part of the MIT design), and (b) you need to be able to reject a lot of waste heat (so running your laptop on one of these means you'll be blowed 200+ watts out the back).

Not that gas turbines are without their advantages. Their specific power (weight per kW) is very good, so for the same amount of power the engine is very light compared to most other engine types (which is why they use them in aircraft). They also start and stop quickly compared to steam turbine systems. And they can be nicely combined with other systems like a steam system to make a combined cycle, the whole system can be fairly efficient.

But, by themselves, they aren't all that efficient.

exaust

[tubbtubb]

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 . . .

no kidding dept.

[lottameez]

While there are still a few hurdles to overcome...
Ya think?

Geese

[Anonymous Coward]

Do these things still make a horrid mess when they accidentally suck geese in through the intake?

Can we PLEASE STOP linking to this guy's blog???

[sczimme]

In all seriousness, why does /. continue to link to his ramblings instead of to articles that contain real, useful, technical content?

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.

Roland...

[addie]

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

Roland

[Lord_Dweomer]

Yet another Roland story. You know, you'd think that if there was enough outrage about this (which I'm SURE the editors are more than aware of) they would have the common decency to listen to their readership instead of just posting more Roland stories.

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.

1 million rpm?

[museumpeace]

I saw this in TR yesteday and, given my dismal batting average with the /. eds, just let it slide.
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 is

1000000*60*2*pi*0.6/(12*5280) = 3570 mile/hour

and 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 ?

Re:Fear...

[uujjj]

Any Amish /.ers willing to back this up?