From: ham789@netzero.net   
      
   On 5/2/2013 12:32 AM, Morris Dovey wrote:   
   > On 5/1/13 10:44 PM, mike wrote:   
   >   
   >> Oh, Morris...say it isn't so!!!   
   >> You've gone over to the dark side.   
   >> You had a wonderful, easily reproduced solar dwelling heater.   
   >   
   > It’s still there. It’s being reproduced. The goals I set for myself have   
   > been achieved, and people are welcome to use (or not use) what I   
   > learned. Additional improvements are possible, but the project I   
   > undertook is completed. :-)   
   >   
   >> I tried to read your links, but couldn't get the videos to play.   
   >> I did skim the MHD book. I'm not the slightest bit interested   
   >> in reliving math experiences from 50 years ago...but there were   
   >> some interesting statements glossed over.   
   >   
   > Agreed - some even intentionally. :-)   
   >   
   >> MHD seems to work with a uni-directional flow of ionized material.   
   >> If you're sloshing it back and forth, there are all kinds of   
   >> issues with reversing the flow of massive ions. And there's the   
   >> tiny detail of superconducting magnets. And the 0.2Volt output.   
   >   
   > “Sloshing” isn’t strictly inaccurate, but in order not to lead anyone   
   > astray, let’s be clear that what’s oscillating is an ionized gas with a   
   > substantial push at one end and a (synchronized) substantial pull at the   
   > other end.   
   Would be interesting to see the theory.   
   I'm concerned that the operation might be extremely sensitive to the   
   temperatures at each end and the middle.  You need physical dimensions   
   and masses to be well tuned to maintain the oscillation.   Solar input   
   is not known for stability.   
   I think you're talking about a LOT more than a pipe with hot water in it.   
   If you table the MHD issues and just build the pipe, does it oscillate?   
   You should be able to calculate the mechanical energy available from the   
   mass of the supercritical water.  Put some lossy compressible   
   material in the end caps to simulate taking energy out and see how that   
   affects the system.   
   Sounds like an evening project.   
   >   
   > I’m interested in using supercritical water for a number of reasons   
   > which include cost and availability, its super-solvent characteristics,   
   > and its R-constant (from PV = nRT). Especially I’m interested in the   
   > dP/dT behavior (the change in pressure relative to a change in   
   > temperature) in the operational temperature range.   
   >   
   > Some of this stuff seriously offends my intuition. Just the idea of   
   > completely dissolving a substantial quantity of (for example) common   
   > table salt into a gas is a bit ‘creepy’ - and that’s not the worst of   
   > the creepyness. :-)   
   >   
   > Superconductivity isn’t part of the design.   
   >   
   > Yes, an oscillating flow does require design consideration - but an   
   > oscillating flow is still a flow in one direction followed by a flow in   
   > the opposite direction. If the magnetic field remains constant, then the   
   > result will be AC, and if the magnetic field is reversed at the end of   
   > each “stroke” the result will be pulsed DC (as if AC had been fully   
   > rectified) - yes?   
      
   I'm trained as an electrical engineer.  I know just enough about physics   
   to be dangerous.  I don't have the answers, but I do know enough to ask   
   questions ;-)   
   Here's my concern about that...   
   If you have a plasma flow in one direction, the charges are "bent"   
   in response to the magnetic field.  Given enough distance, you can make   
   all of them hit the collection plates...EXCEPT...   
   If you let charge/voltage accumulate on the plates, they also repel the   
   incoming charges.  That's why the paper discussed 1000AMPS at 0.2V.   
   Sounds like big numbers, but it's only 200W.   
   You have to hold the voltage down, or increase the magnetic field.   
   Getting that 0.2V converted to 12V or 120V efficiently is a non-trivial   
   task.   
      
   Consider the sloshing.  I have no idea the waveform, so I'll just talk   
   about it as a sine wave.  For a significant portion of the time, the   
   rate of flow is small and producing almost no power.  If you look at the   
   amount of power you can get out of a sinewave with peak value of 0.2V,   
   I think you're talking about something like 40%.  Strike one.   
      
   The ions have mass.  Consider an ion in the middle of the stream.   
   With a DC field, you can get the ion to the collection plate...eventually.   
   If the direction is changing, the ion gets sloshed around in the center   
   of the plasma and never makes it to the collector.  Depending on the   
   frequency of oscillation and the mass of the ion and the distances, it   
   may or may not make a huge difference in how many ions can be collected.   
   Strike two?   
      
   Reversing the magnetic field each cycle sounds easy, until you do the math.   
   The magnet is an inductor.  If it's not a superconductor, it has lots   
   of resistance.  And the magnetic field represents substantial stored energy.   
   You have to dissipate that energy and put it back in the other direction   
   every cycle.  I can't think of a way to do that other than resonance.   
   So, you have a sinusoidal magnetic field that drops the efficiency more.   
   Although, that may mitigate the issues with having to change the direction   
   of the ion flow.  The devil is in the details.   
   It may be more efficient to generate AC and use a transformer to get   
   higher voltage to rectify by conventional synchronous rectifier technology.   
   Strike three?   
      
   My guess is that, by the time you get it working, you'll find   
   that all the little details have reduced the efficiency too far to be   
   useful.   
   And simplicity and ease of maintenance will be far in the rear-veiw mirror.   
      
   I'm not blind to the fact that, if everybody thought like me,   
   there would be no technological advances at all.   
   Who, in their right mind, would even consider making explosions   
   that push things up and down making things go round and round   
   fueled by stuff not yet invented...with chains and levers and rods   
   and unimaginable complexity? ;-)   
      
   If you have a novel idea that's never before been considered, your   
   chances of success are very small.  If your "idea" has been   
   worked on for a century by the best minds available, success seems   
   remote indeed.   
      
   Probably the reason I got fired from my last job...   
   I stood up in the executive staff meeting and drew a tiny circle   
   and a huge circle on the whiteboard.   
   The market wants features we can't produce, despite years of   
   concentrated development.  We don't even have a theory that   
   predicts success.  Best I'd done was show them a "trick"   
   to double the output.  And it had nothing to do with technology.   
      
   We're the number one investor in our technology.   
   We're the small circle.   
   Investment in the competing technology is the big circle.   
   Who do you think will win?   
      
      
   [continued in next message]   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)