On Sat, 23 Aug 2008 19:06:04 -0700 (PDT), "
wrote:
Bruce, you seem to have a quite a bit of know-how in a lot of
different subjects, not only electricity but autos and even steam
engines. I don't know if you are serious about building a turbine
driven alternator but here is an idea about using an old turbocharger
for a steam turbine.
http://www.fieldlines.com/story/2008/1/13/214327/136
If I can line up all the pieces, then I might think about actually
building a steam launch - I can get a good used fiberglass dory or
catamaran style hull and a lot of the necessary marine hardware for
practically free. But I hate getting started on something I know
can't be finished, because either the parts don't exist, they're too
expensive to buy pre-made, and/or it'd cost too damn much to invent
them from scratch.
I've found scale turbogenerators for 1.4" - 1' Live Steam Railroad
engines on teh intarwebs, but they're 6V 0.5A which isn't enough for
me - But it would be perfect for a bicycle headlight and taillight.
(Though for $500 you could buy a whole lot of D batteries...)
For a steam launch you need to run the oil burner, navigation and
cabin lights, bilge pump and other auxiliaries you need roughly 12V
30A to charge the batteries.
A plain old car alternator would be perfect, now you need a constant
2000 to 4000 RPM power source to drive it - too fast for a piston
auxiliary engine unless you use a step-up geartrain, and adding
complexity is bad. And running an alternator off the prop shaft is
iffy, because the main engine stops - though having two alternators
(like two feedwater pumps) would be perfect.
I'll go look, but turbocharger turbines are built for a LOT more
flow and 50K - 80K shaft RPM, much higher than an alternator needs.
The perfect thing would be a turbine section (and the speed regulation
gear) from an old Pyle National railroad turbogenerator, toss the
generator section and couple up a Delcotron.
As to figuring it out, it's all simple machines when you strip off
the falderol. And I have friends who work with them on a regular
basis, so you pick up on the nuances.
A Vertical Firetube Boiler is more designed for marine uses, and you
don't toss them around that much. The usual placement of the steam
taps on the top edge of the drum will pick up water if you toss the
boiler around violently, unless they put internal baffles around the
boiler outlet fittings to prevent it - just like the sectioning
baffles in a tank truck keep the cargo from all rushing to the front.
The whole reason for a steam dome on a horizontal locomotive boiler
was that they DO accelerate and brake hard, go up and down hills, make
turns at speed, etc. Putting the steam dome and throttle valve in the
center highest point was to keep from working water if at all
possible.
They also have this little problem with the crownsheet being exposed
and overheated going down hills, but we don't need to go into what
happens after that...
I have another question for you or the group:
I have had problems with the heat from the lower boiler housing
causing tire blowouts.
The housing gets red hot in places and is inly about 1/2" from the
tire.
there is no way that I know of to fasten insulsation to this surface
that will stand the temperature and rough handeling so I'm making a
heat shield.
I'm using a piece of 20 ga. stainless and tack welding it to the
boiler housing.
I picked stainless for it's poor heat conductivity and I'm polishing
the inside surface to reflect radiated heat.
My question is whether it would help to polish the metal on the tire
side also?
Engineman
Myself, I'd redesign the boiler mounting bracket out a little
farther to gain another inch or so between the boiler shell and the
front tire, you need a little more space to work with. Then make your
heat shield.
And if a simple heat shield won't do it, make a sandwich heat shield
- two sheets of metal riveted at the edges with 1/2" of Kaowool or
other high temperature refractory insulation in the middle. And go
all the way down the side of the boiler to stop all the radiant heat
on that side.
The heat shield can't be in direct contact with the boiler shell, or
it will conduct the heat. You need to mount it off on brackets or
tabs, to break the conductive path. Go look at the heat shields on a
catalytic converter.
-- Bruce --