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PoWaKiD42
07-13-2007, 01:06 PM
Hi, i didint know in wich forum to put my question but i chose put it here, because it envolves steam, its a 'jet' engine, but with steam...

http://www.newscientist.com/data/images/ns/cms/dn3321/dn3321-1_843.jpg

pauluk
07-21-2007, 02:55 PM
Hi,
My gut feeling is that it won't work due to the amount that the steam contracts when it condenses. Saturated steam at 100 psi has a volume 237 times greater than the water it came from. I can't see how the implosion of the steam as it condenses could be used to produce a high pressure stream of water. But then again I might have totally missed something. I would have thought that looking at the principals of a steam locomotive injector might be a better way to go. You can then choose between a high velocity low pressure jet or a low velocity high pressure jet, or something in between.

Regards

Paul

rickharris
12-09-2007, 12:01 PM
I also instintivly feel the answer is no it doesent work or at least not for the reasons given.

A water ram jet aught to be possible though - perhaps a sort of water piston Stirling engine/V1 doodlebug type ram jet. sort of like this:

http://picasaweb.google.com/rickharriss/WaterRamJet/photo#5077660197186628146

Concept not yet proven but the front has a vane type valve allowing water in, the the displacer moves air above the water column from hot to cold (plenty of cold in the average river!) causing the water column to be expelled through the rear of the jet pipe.

As the air cools more water is sucked in thorough the front valve to repeat the cycle. The displacer is either driven from a turbine off take in the water jet or a relatively small electric motor as the displacer need not be heavy.

merl
01-01-2008, 12:22 AM
looking at the device shown above I see a couple things that look like they might add upto somthing and a couple things that don't.
The restriction at the inlet seems wrong because the intake water in this situation could not be compressed by mearly drawing it in through the intake plenum so a certain amount of forward thrust would be negated at that piont.
At the next stage the intake water enters an area of "loose water" or water with a lower cohesion because of the air bubbles.
It would seem that because the itake water is entering this "area of lower density" that it may be able to gain a certain amount of velocity and produce some thrust at least untill it encounters the "area of steam condensetion"
It would seem that the location of the condensing activity within the structure would be critical to its operation.
If the condensing area is too far back inside the exit tube it would likly draw a collum of water in from the exit end and create a stall of the entire system if you're lucky( an explosion if you're not)
If you could tune the whole thing to produce a strong "eductor " effect I could see were this would work but, just how well.....?
It would be an interesting project though.