Requesting Small Sternwheeler hull design and analysis help

Discussion in 'Boat Design' started by phrogjlf@yahoo, Nov 18, 2014.

  1. phrogjlf@yahoo
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    phrogjlf@yahoo JL Frusha

  2. gonzo
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    gonzo Senior Member

    That needs a compressor and a high pressure boiler.
     
  3. phrogjlf@yahoo
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    phrogjlf@yahoo JL Frusha

    10 atmospheres. ~150 PSI. The compressor helps increase efficiency, using it as both a fluidic lubricant and a stirring mechanism to aid the condensation of the steam, but is not absolutely necessary. It works off implosion, rather than expansion. Steam condenses on contact with the water, creating a low pressure zone that sucks the water in from ahead of the restriction. I have a pdf of almost the complete patent, drawings and several variations. Same principle as the Newcomen atmospheric engine, in the early 1700s. Been studying this booger since I first heard of it, about 20 years ago. Parts of the patent date to the late '80s, while the 1st serious patent dates to 1991.

    Bleed a small portion of the steam off, to drive a small motor, which powers the compressor and a generator (or alternator), a water make-up pump, and use the rest for propulsion. As an aside, there should also be steam for the proper use of steam whistles... ;)

    Name has changed several times and it is almost completely out of the news. Just the need for a compact, efficient, modestly powerful outboard made me think of it. Pipe dream.

    Now all I need is a winning lotto ticket for the Grand Prize, a foundry, a machine-shop, unlimited supplies, and a few dozen assistants... :D
     
  4. johnhazel
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    johnhazel Senior Member

    Odd that, after 20 years of study, you describe it as Newcomen based principle and yet the link you gave says "..based on the principle of the aeronautical ramjet engine.."

    but it does have condensing steam creating a reduced pressure.....

    Actually it seems more based on a pulse jet principle with the smooth inlet and sharp edged outlet of the entrance cone acting like a fluid diode coupled with the shock waves of the collapsing steam pockets. V1 buzz bombs used actual flapper valves.

    Either way this is a good example of scamming for some military research grant money.

    Can you imagine what an underwater pulse jet would do for stealth?
    And if that's not loud enough there is the corrosion scraping system to run the peroxide combustor they propose.

    I have a passive acoustic homing torpedo to shoot at this...
    They sure wont hear it coming.
     
    Last edited: Nov 26, 2014
  5. WindRaf
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    WindRaf Senior Member

  6. phrogjlf@yahoo
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    phrogjlf@yahoo JL Frusha

    The water moves as does air, through a ramjet. That action is similar, but the difference is how. A ram-jet uses combustion to add heat and expand behind a restriction, rather than imploding and drawing more in. A ram jet pushes against the restriction, and out the back, this thing pulls water into the front.

    From a practical perspective, the end result is forward motion, with a fluid moving through the thing, by the action of all the working fluids.

    It still depends on a heat differential, so the source of the steam isn't really relevant. Without a working model, and an underwater microphone setup, I would have no way to know if the motor is silent, or not, but, since there is no combustion within it, I would expect it to be silent. Definitely quieter than an ICE.

    Personally, I would think using an arc, to melt the Aluminum, would be more efficient than using multiple chemical reactions, but the cost of Aluminum is the prohibitive yardstick... The Al/H2O reaction releases Hydrogen, as well as creating steam, so these reactions were studied in an attempt to get cheap Hydrogen for fuel cells. Again, the cost of Aluminum is too high to make it practical.

    Fortunately, we can use a flash-boiler, instead of relying on an expensive chemistry experiment. UN-fortunately, this thing is not available, so we'd have to make it ourselves. :(
     
  7. johnhazel
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    johnhazel Senior Member

    A ramjet depends on having more gas volume leaving the tail pipe than it does entering. Your collapsing steam is doing the opposite.:( Let's just pay no mind to all that.

    Instead, could you explain how the collapsing steam only pulls on the water in front of it? And then, if you please, tell how the steady state propulsion, where the steam bubble is constant sized since new steam is replacing the collapsing steam, How does this constant volume pull on any of the water around it?

    Maybe now you are ready to take a look at the pulse jet concept again? If not take a look again at the link you gave. How do you explain the animation showing pulses in both ends of the drive?

    Yeah, troublesome, that issue of no working model....:rolleyes:
     
    Last edited: Nov 26, 2014
  8. Rurudyne
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    Rurudyne Senior Member

    I remember reading about these and, yes, they would work ... but the problem that I can see is the need for steady water to a boiler because unlike Rankine cycle engines there's no recovery of the working fluid. If the water you run in is relatively clean that's not much of an issue ... but even then I'd want a boiler where cleaning out accumulated muck would be easier.

    Now, that said, if you were already using steam one of these might possibly be good for a bow thruster set up as these are used intermittently.
     
  9. johnhazel
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    johnhazel Senior Member

  10. johnhazel
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    johnhazel Senior Member

  11. phrogjlf@yahoo
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    phrogjlf@yahoo JL Frusha

    It's not mine and it is an old design that is not being exploited commercially. Just because some graphics artist doesn't understand the difference between a steady-state ram jet, a pulse jet and a steady-state implosion, doesn't mean I have to explain the differences.

    Experiments show that it works, science describes how. An artistic rendering is just that, and not necessarily accurate. If you look at the design, you can see that the steam entering the water-jet uses the Venturi Effect, to create a direction of initial flow. A ram jet has to have that flow to begin with. The implosion of the steam (spontaneous condensation) is a natural phenomenon. The reduced pressure zone pulls in more water. The mass of water flowing in, as well as the restriction create a tendency to continue flowing in one direction. My best guess to the screwy description, and animation as a pulse jet is that it was compared to the pop-pop type toy steam boats.

    As I said, this relies on implosion... A reduction of volume, rather than expansion, so it actually functions in the opposite way that a ram jet does. Rather than forcing expanding fluid out the rear, it pulls water into the front. If you actually take the time to look, BOTH are somewhat funnel-shaped. A ram jet has the larger opening facing aft, while this has the smaller opening facing aft. A ram jet pushes more out, this pulls more in, working in exactly the opposite fashion.

    Moot point. I don't have one, would need a foundry, a machine shop and funds that I don't have to make a one. The whole reason I even brought it up was the power requirement, comparing trolling motors, electric outboards and gasoline outboards. This thing itself is roughly the size of a trolling motor and more efficient than either. It STILL needs a source for steam. It may be able to function on compressed air, but not as efficiently.

    Not my monkey, not my circus. IF, however, you would be so kind as to fully fund the endeavor, I COULD build a self-contained unit, roughly the size of a large outboard unit, IF I scavenged a large outboard for the structure. I have no idea what the final cost would be, but I'd have to set aside almost everything else, while I do so.
     
  12. Rurudyne
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    Rurudyne Senior Member

    Incidentally, that pulse jet tech was invented to use mainly as a mixer.
     
  13. gonzo
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    gonzo Senior Member

    How is that jet going to work in your sunk in the mud scenario?
     
  14. phrogjlf@yahoo
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    phrogjlf@yahoo JL Frusha

    NONE of them, no matter what, are going to work if she's high-and-dry, or the lower-unit is in the muck. The one, absolutely Sternwheeler-like hull function I need is the transition, up to the transom, and to elevate the drive above, or at least, even with the lowest point of the hull.

    I don't want anything other than chine logs to extend below the hull line. I have to keep stuff out of this muck.

    Another thing this steam jet doesn't have is reverse... The lower-unit would have to rotate 360* to give that function to it.
     

  15. gonzo
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    gonzo Senior Member

    An outboard can be tilted half out of the water and still push the boat. A jet drive like you show, will suck mud and debris and stop working in short time. If you really have to go in water so shallow all the time, a conveyor belt type drive may be an option. Look on youtube for snowmobiles going over water. There isn't any option that beats a propeller for efficiency, but a belt will actually push on the mud. The other option is an airboat. They go over mud, grass and on the road too.
     
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