Two Tiny Gas Turbines 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.
Re:Warning (Score:2, Informative)
I would worry about dust, sand, bugs and other small bits getting pass the air inet.
http://en.wikipedia.org/wiki/Gyroscope [wikipedia.org]
Re:Inefficiencies? (Score:5, Informative)
6000C combustion? (Score:4, Informative)
Re:Inefficiencies? (Score:5, Informative)
Re:Inefficiencies? (Score:3, Informative)
Re:Power generation (Score:2, Informative)
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.
Article close to pure crapola! (Score:5, Informative)
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.
This is a DARPA spinoff (Score:3, Informative)
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.
Re:6000C combustion? (Score:4, Informative)
Re:Article close to pure crapola! (Score:3, Informative)
Methinks some slashdotters have reading comprehension problems. The BBC article which mentions 95% is about a Swiss generator, not a turbine. 95% is quite reasonable for a small generator. The article only mentions turbines in passing, noting that one could be used to drive the generator.
Re:Uncontained turbine failure = bad Ju Ju (Score:3, Informative)