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| Flames and flame suckers and eaters |
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| NickG:
Hear hear Jack, nice speech for all of us like minded people. Bill, I guess it's easier to control the efficiency of the stirling, wasting as little heat as possible must be the starting point, then it must be largely down to the conduction of the heat - as you said there are ways of improving that, I believe different gases can be used also. The actual concept and the cycle of the stirling must be quite high efficiency though? eg, low temperature differential engines can run on very small differences in temperature - i know they give little power but the fact that they can take such a small amount of energy and turn it into motion is impressive! Sounds interesting with the magnet but the downside would be the friction it creates for the sliding valve and you may get friction latching - the valve may stay stuck longer than required as it's opened by a light spring. That could be solved by other methods of driving the valve though. Nick |
| John Hill:
--- Quote from: BillTodd on March 26, 2011, 12:30:41 PM --- --- Quote from: madjackghengis ---So, to start it off, many have asked about flame propagation, and how flames enter the cylinder, --- End quote --- I've just been it the 'meditation' room thinking about this: Since the plasma is conductive and moving it might be possible to improve the inlet with a ring magnet - thus forming a sort of plasma conduit (yes, I can feel the tips of my ears getting pointy as I type ;) :borg: ) The magnet could also help to seal a steel valve sheet over the hole. Once inside the cylinder, good highly polish surfaces would help to keep the plasma hot (by reflecting those energetic photons back into the centre) while the valve closes. Bill --- End quote --- Bill, you could fit a magnet or two to the flywheel with a coil to generate a pulse at the right time to energise a coil around the inlet port.. :scratch: |
| John Hill:
There must be scope for a tuned draught tube. If there were seperate inlet and exhaust ports a tuned tube on the exhaust would suck the last of the 'cold' gas out and enhance the sucking of hot gas/plasmas in. I should stop having these dreams and make a basic one first... :lol: |
| andyf:
Might the explanation for improved running when the engine has warmed up be simply that when the inlet port and valve it are cold, the hot gases (flame + air) are cooled down a bit as they are drawn in, but after a while the flame heats up the valve and port area so this cooling on the way in doesn't occur? Just a thought from a simple soul.... Andy |
| madjackghengis:
Hi all, good to hear all the differing ideas, and perspectives, I will say, Andy, the port area definitely warms up, and that certainly is a big factor, based on observation, and in my last engine, I did taper the port to supply the smallest contact area with the air going in, and believe the statement made by the fellow who designed the "poppin" was dead on with regard to design correctness on that. I've taken a small butane torch, and aimed it up the port while the alky flame was running the engine, expecting to get more energy out of it, but had little effect at all. In analysing it, I think I was also pulling in cool air via the Bernoulli effect, and I think John's idea of a tuned tube with a pressure fed burner would be effective in matching the natural pulse effect of the engine with a timed pulse flame, and would probably improve the efficiency of the engine. I've been considering a two or four cylinder engine with two cranks, and the heads close together, so with their timing 180 out they could use a common flame being sucked back and forth, with a manifold length to provide a timing effect from the flow length and port diameter. I've also considered a V twin with each cylinder on its own crank pin, and the timing of the two being similar to the previous example, but offset by the cylinder angle, and with a "Y" shaped manifold, with the flame flipping back and forth within the manifold from port to port. These flame eaters were the direct precursers for internal combustion engines, and it is so often said the primary reason for the worst of the pollution is the compression allowing the high temperatures, so if we could come close to achieving thermal efficiency with an external burner, we would eliminate the worst of the pollution, and still have the energy. That remains the Stirling's prime attraction I think. cheers, Jack |
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