On 21/04/2011 14:09, Andy Breen wrote:
On Thu, 21 Apr 2011 12:49:14 +0100, Graeme Wall wrote:

On 21/04/2011 11:32, Andy Breen wrote:
On Thu, 21 Apr 2011 11:25:50 +0100, Graeme Wall wrote:

On 21/04/2011 11:04, Andy Breen wrote:

Steam motor actually makes sense in the context I was using as it is
an external combustion engine, as is an electric motor. An analogy
that breaks down as soon as you introduce hydro/wind/tidal power into
the equation :-)

Isn't a water turbine a hydraulic engine? ;-)

Told you the analogy broke down when you introduced water, it stops the
combustion...

Not always. You can get a significant power boost by injecting a fine
mist of water into the air intake of an otto-cycle engine (it cools the
fuel/air mix, increasing its density and thus the amount of mix delivered
to the cylinder). Water injection was a hardy perrennial in aero-engines
in the piston-engined days, either for emergency power boost or for take-
off. Also used by the drag-racing boys, of course..

Actually, on reflection, you can use it with diesels too, as a way of
cooling the air charge (after, I think , compression by the supercharger)
and allowing more fuel to be injected per stroke. The Napier Nomad used
water injection for power boost..

;-)


Didn't someone try spraying a fine mist of water into steam engine
cylinders to condense the steam quicker?

--
Graeme Wall
This account not read, substitute trains for rail.
Railway Miscellany at www.greywall.demon.co.uk/rail

On Thu, 21 Apr 2011 14:51:24 +0100, Graeme Wall wrote:

On 21/04/2011 14:09, Andy Breen wrote:
On Thu, 21 Apr 2011 12:49:14 +0100, Graeme Wall wrote:

On 21/04/2011 11:32, Andy Breen wrote:
On Thu, 21 Apr 2011 11:25:50 +0100, Graeme Wall wrote:

On 21/04/2011 11:04, Andy Breen wrote:

Steam motor actually makes sense in the context I was using as it is
an external combustion engine, as is an electric motor. An analogy
that breaks down as soon as you introduce hydro/wind/tidal power
into the equation :-)

Isn't a water turbine a hydraulic engine? ;-)

Told you the analogy broke down when you introduced water, it stops
the combustion...

Not always. You can get a significant power boost by injecting a fine
mist of water into the air intake of an otto-cycle engine (it cools the
fuel/air mix, increasing its density and thus the amount of mix
delivered to the cylinder). Water injection was a hardy perrennial in
aero-engines in the piston-engined days, either for emergency power
boost or for take- off. Also used by the drag-racing boys, of course..


Didn't someone try spraying a fine mist of water into steam engine
cylinders to condense the steam quicker?

Someone did. Actually, several someones did, starting with an ancient
Alexandrine (so far as we know..), but it's usually associated with
Newcomen who was the first to do it with a significant number of engines.

Before Newcomen, Savery had been spraying a fine mist of water into the
boiler to condense the steam to provide the vacuum needed for pumping.
Newcomen combined Savery's condenser with Papin's piston-in-cylinder and
- well, here we are today, arguing about the definition of
"engine" (with, no doubt, some of us looking it up via a search *ng*n*..)

--
Andy Breen, not speaking on behalf of Aberystwyth University "The
internet, that wonderful tool for bringing us into contact with things
that make us wish we could scrub our brains out with dental
floss.." (Charlie Stross)