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| vtsteam:
Brass Machine thanks!! I think I'd favor a conventional boiler for stationary models, too. I have a few I'd like to get working some day. I hope this thread will at least be interesting, even if the results don't pan out. |
| vtsteam:
So to conclude -- the big problems I've been thinking about in monotube boilers are tube damage from overheating, tube damage from excess air, control and stability problems in steam production, cost inefficiency, exotic materials requirements, and system complexity. What I'm tending to favor to try to mediate the problems are: 1.) a horizontal design 2.) a parallel flow or random flow design 3.) a heat exchanger located largely past the combustion area 4.) reduction of excess air 5.) wood fuel 6.) a relatively constant load style of electric generation These are not the common choices in monotube construction or design today, in fact added together they are pretty much the opposite of conventional wisdom. It is not the way to do things if the greatest value of heat exchange and temperature is desired from a monotube. However, it might actually be a practical response to the conditions and assumptions I gave in the first post, and so efficient in that sense. In other words, it might be good enough for who it is for. |
| R.G.Y.:
Beeing a boat man I think the horizontal design will have a lower CofG, for a longer coil as in steam hydroplan racers. :mmr: |
| vtsteam:
Yes RGY, that's very true. :beer: And it can also be longer if it is horizontal and still fit tween decks. Which can mean easier heat conversion over a longer length of heat exchanger. On a slow boat, though, we need a stack, so lose some of that layout advantage (unless there's a blower). Fast boats like racers use ram air to provide oxygen to the burner, flow through the exchanger, and to clear exhaust. |
| fcheslop:
http://www.modelboatmayhem.co.uk/forum/index.php?topic=24568.0 http://www.modelboatmayhem.co.uk/forum/index.php?topic=15817.0 There maybe some info in these threads and E T Westburys Experimental Flash Steam book is pretty good I did play with flash steam in the early 80s before the advent of cheap electronics and found for marine use a simple figure of 8 worked well. Good luck best wishes frazer |
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