Humidity

[John Hess]

Many military aircraft use water injection for take-off power
augmentation.  They go one step further, though, and general use a
water/alcohol mix.  It is called ADI (Anti-Detonation-Injection).  It
has the multiple function of cooling the intake charge, increasing the
intake density, and (after breaking down) increasing oxygen AND fuel
entering the engine.  Worked on piston AND turbine engines.



> ----------
> From: 	Charles Fulton[SMTP:cf352197 at oak.cats.ohiou.edu]
> Sent: 	Monday, September 22, 1997 6:30 PM
> To: 	diy_efi at coulomb.eng.ohio-state.edu
> Subject: 	Re: Humidity
> 
> 
> 
> Frederic Breitwieser wrote:
> 
> > >Why is that when humidity goes up engines make more power???  My
> thinking is
> > >that if the air is more humid (AT THE SAME TEMP) there is less
> oxygen,
> > >therefore less engine power.  Also the humidity's temp. increase
> takes away
> > >some of the energy, making less available for pushing the piston.
> Any hints
> > >on this subject??
> 
> When water is subjected to high temperature and pressure (like in an
> engine) it
> will break down into its component hydrogen and oxygen and actually
> become fuel.
> That's why you don't use water to put out a magnesium fire.  It works
> just like
> nitrous oxide, except that the hydrogen from water is more willing to
> burn than
> nitrogen so it should work better than nitrous.  Water injection, I
> believe, was
> popular on tractors,  and has been attempted on a few drag cars.
> Though NHRA
> made it illeagal, I guess the cars went too fast.
> 
> Charlie
>