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On Mar 11, 1:22 am, "Ed Huntress" wrote:
Has anyone ever built a model of a de Laval turbine? I mean one with a
real
de Laval nozzle, that put out some power.

Or do you know of a good text about them? Most are either too simple or
they're too abstract on the engineering theory side.

I'd like to build a model of one, but not just a steam windmill. g I'd
like to have some real de Laval nozzles on it.

Thanks to any steamers who know about these motors.

--
Ed Huntress

Maybe you can find a copy of:

http://www.lib.ncsu.edu/findingaids/mss00090/#IDAVNIQ

Some info he
http://www.thespacerace.com/forum/in...p?topic=2595.0

Looks like the critical bit of science is the nozzle accelerates the
steam jet to the speed of sound (and above? I assume speed of sound
for the material being run through the throat)...

Right. Which is much higher than the speed of sound in the atmosphere.

...in the constriction,
then the jet hits the divergent part of the nozzle and speeds up yet a
bit further.

I forget most of the dynamics, but it's pretty wild.

Interesting stuff, and doubly cool since that principal is used in
rocket nozzle design.

So anything convergent-divergent is a de Laval nozzle.
Sounds like you could test nozzle designs just by measuring the speed
of the output jet (somehow!).

Well, de Laval invented the thing (I think), so they use his name on it when
it's applied to steam turbines. There are old engineering texts I've seen
that provide formulas for all of the dimensions, based on steam temperature,
superheat, pounds of steam produced, and so on.

I like the brief mention he
http://www-istp.gsfc.nasa.gov/stargaze/Sgoddard.htm

" Nowadays steam turbines are the preferred power source of electric
power stations and large ships, although they usually have a different
design--to make best use of the fast steam jet, De Laval's turbine had
to run at an impractically high speed."

An impractically high speed- that makes it a cool project right there!

Dave

Even the little ones made for doing farm jobs, around the turn of the 20th
century, turned at speeds around 30,000 rpm. I have no idea how they held
together, given the state of metallurgy at that time.

--
Ed Huntress