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..

;-)

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