Re: Water injection ?

From:         eirikur@ix.netcom.com ()
Organization: Netcom
Date:         31 Oct 95 00:31:27 
References:   1
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gernot@vmars.tuwien.ac.at (Gernot Auer (Prak 1 Gerhard)) wrote:

>Is there anyone who can support clues how 'water injection' in any way could
>effectively increase engine power?

>We were discussing about how water as material itself could increase
>the quantity of boost generated by the engines in first place, and thus
>increasing the overall power. Any possibility this theory could make
>it ?

Gernot,
     Jet engines operate with much greater efficiency when they
consume air that is cool and dence. That is to say that under these
conditions, a larger quantity of air may be consumed at the same rpm.
The conbustion process is more efficient with a higher air to fuel
ratio for example,  on a hot dry day jets generate less thrust than on
a cold humid day. This phenomonon lead to the advent of water
injection for use on some older jet engines.  Forcing water into the
inlet  reprocuced the effect of a colder, more dence operating
environment.  Remember, also,  that as the air passes through the
compressor, it heats up due to friction.  Depending on the engine, the
air is usually at several hundred degrees F before it reaches the
combustion chamber.  Keeping this in mind, one is able to see that the
water injected  into the engine has become water vapor by the time it
reaches the combustion chaimber.  Hopefully I have helped you
understand how and why water injection is used.  If you have any
further querries, you may e-mail me or post to the net any time.
JCD USAF AVMAINT.