Hybrid Car – More Fun with Less Gas

Anybody know where to get a small steam turbine? - Page 12

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Posted by Ulysses on March 25, 2009, 4:29 pm

Neighbors eh?  I don't have any of those.  Besides, I doubt high frequency
interference is going to have much effect on digital TV transmissions.  I
don't know about radio--is it still analog?

Posted by Curbie on March 25, 2009, 8:41 pm
Just an attempt at a joke. Although when I use my electric egg beater
it kills my "over the air" digital TV.


On Wed, 25 Mar 2009 08:29:00 -0800, "Ulysses"

Posted by vaughn on March 25, 2009, 12:04 am

There is far more to it than that.  A multi-stage turbine must get
progressively larger as you move down to lower pressures..  Size and cost
increase geometrically.

But piston has some of the same problems as turbine.  To get really
efficient operation, you need two or three stages of expansion, each stage
being much larger than the one before it.  The more you look at steam, the
harder and more expensive it gets!

One "dirty" design for a multi-stage piston engine has been in the back of
my mind.  It is an engine based on a 6 or 8 cy automotive block.  The
highest-pressure steam would go to only one cylinder.  The expanded steam
from that cylinder would be routed to two cylinders, and the final stage
before exhausting to the condenser would be the rest of the cylinders.  Of
course, the engine would not run smoothly because the various cylinders
would be producing drastically different horsepowers, but I will leave the
solution to that as an exercise for others.



Posted by daestrom on March 25, 2009, 11:06 pm

Sigh.... Yes, there is a lot more.  Like moisture draining between stages,
balancing axial thrust, shaft sealing, pre-warming, even compound units and
on and on.  But I wasn't trying to create an exhausitve list, just one of
the initial 'show-stoppers' for home-built steam turbines.

Well, 200 psi single expansion locomotives opened up the west.  So they
aren't impossible to do.  True, near the end of locomotive steam era, they
used two pistons on each side (or even one underslung in the middle) for
double expansion.  But this is all a question of how cheap your fuel source
is and how mechanically inclined the builder is (and how much time he wants
to spend maintaining the thing).

ICE's make lousy steam engines.  Single-acting piston, have to replace the
inlet valves with ones that remain shut during the return stroke (steam
pressure would tend to open the typical ICE's poppet intake valve).  Keeping
water out of the lube oil system would be a new and exciting challenge.
With only a single, single-acting piston, a large flywheel and some way to
'bar' it over when it stops on the wrong part of the stroke.  fagedaboudit.


Posted by Curbie on March 26, 2009, 12:37 am

I didn't even consider that. In my old car racing days we called water
in the oil "Camel Come" if you don't fix it, the cam will come (out).

On a lighter note.


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