Date: Sat, 05 May 2001 18:04:19 +0100 From: John Griffin <johnnopsamfinphoto.u-net.com> Subject: Re: Water Injection
in article 3AF35964.4D428C95nopsamlobal.net, devil at devilnopsamlobal.net wrote on 5/5/01 2:38 AM: > Jean Luc Monette wrote: >> >> "John Griffin" <johnnopsamfinphoto.u-net.com> a Ècrit dans le message news: >> B718B1C4.79FD%johnnopsamfinphoto.u-net.com... >>> in article 3AF22B14.BCD2D8FEnopsamlobal.net, devil at devilnopsamlobal.net >>> wrote on 5/4/01 5:08 AM: >>> >>>> John Davies wrote: >>>>> >>>>> On Wed, 2 May 2001 23:14:54 -0400, "Jean Luc Monette" >>>>> <jlmonettenopsamotron.ca> wrote: >>>>> >>>>>> Hi all! >>>>>> >>>>>> Actually, water-methanol injection has been used on turbine aircraft >> engine >>>>>> for a very long time. What it does? >>>>>> lowers inner turbine temperature, increases air density since water is >> less >>>>>> compressible than air, thus permitting to produce more power at less >>>>>> temperature inside the engine. Mind you that this is done in a >> controlled >>>>>> fashion, as far as water in a puddle is concerned, I wouldn't want >> that to >>>>>> get in my saab's turbo!!! >>>>> >>>>> My thoughts on water injection: the performance increase is due to the >>>>> dramatic cooling of the incoming air by the rapid evaporation of the >>>>> water droplets. Not because water is "less compressible" than air. >>>>> There is no liquid water by the time the airflow has reached the >>>>> critical parts of the engine. >>>> >>>> Actually, it's because with the water in, the mass of the cycle fluid is >>>> increased. >>> >>> Please explain exactly how increasing the mass of the 'cycle fluid'( and >>> explain this term) can produce more power or cool the in cylinder >>> temperature? >>> >>> The conversion of water from it's liquid form to steam in the cylinder >> uses >>> up the heat of the intake charge. >>> BTW methanol was added to the water in aircraft engines only as an >>> antifreeze which is very necessary at altitude. >>> >> >> Actually John, water-methanol is used on aircrafts which have problems >> achieving their maximum torque when the outside air temperature becomes very >> warm causing them to be temperature limited as opposed to torque limited in >> the wintertime... re: Swearingen Metroliners, Hawker Sideley's 748 and so >> on. I'm very disappointed to tell you that the only way to de-ice or >> anti-ice an aircraft turbine engine in altitude or on the ground is through >> engine bleed air being routed to the engine's intake lip (jet or turbine >> engine) but we're very far from the subject this newsgroup is about: Saabs > > It's all the same idea anyway. Lowering the temperature, you get more > mixture through. But yes it's particularly tough on jet engines in > hot/high conditions. I think there is a bit of confusion here - when I was referring to it's use in aero engines I meant in piston engines in WW2 - they had superchargers and turbochargers and hence it's application. I had no idea it was used in turbine engines today.
 |
 |
 |
 |
 |
