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Steam Powered Underwater Jet Engine
Bob Vila's Hammer writes "An Australian engineer, Alan Burns invented a very efficient underwater steam powered jet engine. "Steam that is produced from a petrol or gasoline fueled boiler emerges at high speed from a rearward-facing ring-shaped nozzle into a cone-shaped chamber. Shock waves created as the steam condenses are focused by the chamber to blast water out of the back. Besides powering watercraft pretty efficiently, it can also be used as an extremely robust pump. Pretty Cool."
From where would you supply the air for the necessary bubbles? If you're in a submarine that's been submerged for say 2 weeks, is there a stable source of air to inject?
~A'Ëq'i4d)^'$ÊSÈòB
From the article: With no moving internal parts, and no propeller, the engine should be cheap to manufacture.
I especially like the part about no moving parts... Moving parts are good to avoid in all cases, when possible... They wear and need replacement. Nice one!
.: Max Romantschuk
"...shockwaves..." This will be damn noisy for those living under water... Noise pollution will increase to the level that those mammals will be no more able use there sonar capabilities
From more to less likely:
(1) Efficiency could peak at 300HP designs - it may be that any larger becomes horribly inefficient. Since it relies on squeezing compressed air and steam into an open tube, there might be a point at which there simply is to much room for the reaction to take place in given an incoming water velocity.
(2) The design may not be completed - possible design flaws may limit this versions' abilities to scale up.
(3) They may simply not know how big it can scale if their simulator isn't powerful enough to run a detailed simulation of a larger engine.
...aren't they the same thing?
I'd imagine that it is to do with getting the air to mix evenly in such a big chamber prior to coming into contact with the steam. Why not just use several? The article doesn't mention it, but I wonder if there is any difference in efficiency for 10x30HP engines vs 1x300HP engines.
Multiple highly reliable drive mechanisms would be desirable for warships, allowing it to suffer damage to the drive, without becomming dead in the water.
Well, I'm sure somone else has noted this : a nuclear energy source like on a warship would be perfect for supplying the steam. By venting the secondary steam from the boilers directly into the water like this you could easily get ten times the power with the same size engine (though you'd need more higher output reactors) I am sure an engine like this would be EXTREMELY noisy, so the warship would have a set of these steam jets it could fire up when it needs to move somewhere fast, and some quieter source when submarines are a worry. Imagine an aircraft carrier and a few destroyer escorts with flank speeds in excess of 70 knots (it would have to have hydrofoils as well, because otherwise the hull speed would be to limiting. Yes I'm aware it might be decades before a carrier this sexy is built, if ever). Sure it would be vulnerable to torpedoes, but the idea is it could be a MUCH more threatening weapon with this kind of speed. It could patrol a larger area, escape from danger, and have a certain intimidation factor when its located somewhere since it could arrive suddenly, launch a strike force, and depart before the enemy was aware.
As long as were speculating, imagine an even more effective weapon, a ship loaded full of missiles and rocket launched drone strike aircraft (so no human pilots risked. Yes I'm aware that such aircraft might be say, half as effective as human piloted planes but if they cost 1/4 as much to build its a MUCH more effective weapon. It could very well be cheaper to turn out somewhat dumb long range missiles and semi-reusable drones by the thousands, with no additional pilot training needed. The "pilots" would be a group of technicians behind consoles far from the battle, with embedded computing in the planes doing most of the flying, the human being just to pull the trigger. Without all the risks of training pilots and maintaining aircraft (the planes would be stored in sealed containers until needed, with a small set used for training) and the fact that these planes don't need nearly the quality control in manufacturing (if you lose 10% of them in a mission due to shoddy construction but they cost half as much or less to build its definitely worth the trade off) you'd have a better solution than at the present.
Why isn't this done already? Well, in the 1970s and earlier where most of the present airplanes were designed, communications technology and computers were not good enough or reliable enough. Today, most of the money is spent on operations and on a couple of new aircraft. Also, the current leadership is made up of pilots, who don't want to be replaced by scrawny pasty faced techs sitting at control stations. Finally, there's a current bandwidth problem : military communication satalleits don't have the capacity for the hundreds or thousands of video links needed.
am wondering how you get this engine started?
:)
That's the exact same thing I was just wondering. The best way for me to find out is to go build one and try it! I'll be sure to make a website once I do it, and after that, I'll try to stand up to the litigation from Pursuit Dynamics
Seriously though, it looks like there's a small venturi at the exit of the steam chamber which would focus the steam backwards and start the process. Also, if you don't have steam pressure (any time the boiler is off overnight), the water will flow in the steam supply line. When you start it, the steam probably pushes the water out, generating a small current that builds as the engine starts working.
- "Nobody came out that night, not one was ever seen. But Old Man Stauf is waiting there, crazy sick and mean!"
This sounds amazing:
* Cheap to produce
* Incredibly robust (no moving parts)
* Efficient (although they don't give any numbers)
* Safe(r) for the environment
* Multiple uses (pumps)
* Scales well in a small package
Without seeing any numbers, it sounds like it beats the pants off of outboard engines. My 70HP Evinrude has been rebuilt twice because of sand-suckage, and standard jet impellers are too inneficient.
So what's the catch? I want to see some real numbers. If there's no catch, then I hope and think this thing will revolutionize the small-craft market.
Water emerging from the engine is no more than 3 or 4 C warmer than the water it draws in, so there is no danger of scalding.
:
It always amazes me to see how technoscientists can draw conclusion so fast as far as it goes in their direction. A difference of 3 or 4 degrees is ENORMOUS ! It can totaly change an ecosystem or current and exchange mode localy.
The boats usualy cruise in the same places
- Big commercial boats have to cruise in well defined corridors when they comme along the coast
- Personnal jetspeed motorcycles (and such) usualy cruise from 0 to 300 meters on the coast
- What about small closed gulfs seeing their nautic population multiplied by 3 or more during the summer.
When you think that coral is dying in some places in the world because the global temperature raised by about 0.5 C or because such or such current has changed is way, I can let you immagine what a disaster on a local level could cause a 3 to 4 C increase !!!
Now, I am not saying that 3 C différence out of the engine will make such a difference on the global level. But saying that such a difference will not be a problem seems a little to fast conclusion to me without any further study...
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If something can go wrong, it will ! (murphy's law)
Well, matching speeds with the fighter may be a little beyond conceivable tech After all, instead of doing that why not just give the aircraft enough range to reach anywhere in the world from a few bases on land, or VTOL capability? It would definitely be easier. Yes I suppose its conceivable to build a nuclear powered hydrofoil carrier thats basically a scaled up racer, but almost unbelievably expensive. But it would certainly help if the carrier were closer to the speed of the fighter, perhaps.
Sure, both this and supercavitation are cool, but they aren't going to play well together. The whole point of supercavitation is that it keeps (liquid) water away from the hull. This guy pretty much needs to inhale as much water as it can get.
You might be able to get away with mounting a ring of jets around the hull near the aft along with (or in place of) the control surfaces, but I'm guessing you'd still get into trouble with the extra turbulence.
I can't conceive how it will function as a primary power source because of the mechanics that would be necessary to start the process.
In the same manner, you won't have a "neutral" since it probably can't be turned off and on rapidly for docking maneuvers, et al. Perhaps it could use buckets like a jetski (or any jet aircraft using clamshell reversers), but I wonder how well it reacts to a high backpressure created by such a device....
Maybe we'll get to see some of that great KABOOM action when these things explode or when two boats collide!
One thought though, if you're doing 90 knots underwater when the sea is full of debris [slashdot.org], you might want really good maps and a kick ass gps+VR rig to guide you through the canyons, because I doubt sonar will be able to image for you fast enough.
The speed of sound in air is over five hundred miles and hour. I don't know what it is in air but if you assume that it is half again as fast in either direction, then it cannot be less than two-hundred and fifty miles per hour, nor more than seven-hundred and fifty miles per hour at the high end.
If things are workable at the low end, the high end is fine. Therefore, the low end is the 'danger zone.' Assuming an active sonar range of one mile. Now, submariners don't like using active sonar, it's analogous to a soldier standing in an empty field at night and shouting, 'shoot me!!'
Be that as it may, working with the assumption that the submariners use it, it is fairly safe to assume that any system they use for detecting objects in their path would be used to provide the most proactive solution to the problem of not running into things possible.
Basically, if you were doing 90 knots when you turned on your sonar system, in a place with potential hazards at close range, you might not like it, but assuming you spent all your time pinging like crazy, it is safe to assume that you would have advanced warning on objects in the distance because your sonar data would let you catalog them before they became a threat to you.
Note also that GPS systems use radio waves which don't work well at all when transmitted through water.
Be that as it may. It is of course true that VR-goggles and GPS techology are both very cool.
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"Yeah. It smells, too..."
since the water is only 3 or 4 degrees warmer after it exhausts from the blast chamber, would trout that has been killed by being sucked up by the engine be in one piece and good to eat if you turned around and began to scoop up your trail of dead sucked up fish? It would be the simplest fishing trip since the invention of dynamite
No. Its described as 'macerating' anything solid it takes in. Basically, you'd get trout soup out of the other end. But then what would you expect - the thing works by injecting a stream of steam into water at faster than sound speeds. That's gotta be worse than just knocking em on the head with a shockwave or two...
Two points.
1. The speed of sound in water is actually faster than in the air (it is related to density).
2. Pay attention to the anticipated speed that they feel can be accomplished with the engine. 90 knots is faster than most torpedoes (ignoring the rocket propelled supercavitating ones). The users of this engine may not care too greatly about being noticed since they can outrun just about anything which could attack them.
You also couldn't reverse the thing the same way you reverse a normal vessel
But with an engine that small and no mechanical or electrical linkage needed to the actual engine - just turn the whole thing around.
You could use it like an outboard/sterndrive affair
On tug craft you could use several to replace the current bucket prob designs.
On large ships you could use banks of these along the hull. If they can orient them then you can spin the vessel in its own length, move it sideways, offset the forward and stern banks to assist the turning. Stopping would be easier as a big stern prop is horribly ineffecient in reverse, but turning the engine pods around would not effect them (Probably - not sure if reverseing the water flow over them may make them less effecient). Want to avoid a collision, just turn them sideways under way and shove yourself out of the way sideways.
The beaty IMHO is this thing is so simple all you need is a pipe and valve to regulate the steam from a central boiler, and a control system to turn it.
This could potential make for very agile vessels.
Well, not exactly. As you can see in the drawings, they add air bubbles to the mix where the Giffard Injector doesn't.
My theory is that the steam mixes with the bubbles, and given the low caloric density of air, these will expand rapidly, leading to a volume increase and therefore providing extra boost. Further down, they mix with cold water and become cool again, but then it's already out of the jet. Should make for interesting current patterns...
The speed of sound underwater is actually about 3-5 times that in air, coming out to a few thousand miles per hour. The sonar is still certainly faster than the sub. :)
:)
The problems with using sonar at those speed, I think, would be due to other factors, such as:
1) Sound waves are scrambled by the medium more easily than light waves (minor temperature or salinity variations are enough to throw the wave path widely off).
2) The noise and turbulence of a high speed submarine itself creates significant disturbances.
Submarines are generally navigated using charts and inertial navigation, not sonar. It's quieter, although inertial navigation is never perfect. Submarines have to surface from time to time to get a navigational fix, usually.
Also keep in mind that a submarine is not a jet fighter, and is not going to pull a 40 G turn to do nap-of-the-submarine-canyon swimming, no matter what kind of drive system you slap on it.