RE: re Re: Ceramic coating EM's - II

["Smith, Kirby A" <kirby.a.smith@lmco.com>]

I get your point, although kinetic enegy is proportional to velocity
squared.  The actual physical effect is molecular momentum transfer to the
blades, which are shaped in a manner to exert work on the shaft while
redirecting the molecules out of the way of the "unused" molecules.  Gas
kinetic energy in the form of heat could conceivable contribute.  If the gas
temperature before the turbine was the same as after the turbine (for the
same size pipe) then all energy is taken from gas flow.  If otherwise, I
would argue that some came from heat.  I will defer further comments until I
have time to check out my sources to see if my head is wedged in this case.

kirby

> -----Original Message-----
> From:	quk@isham-research.demon.co.uk [SMTP:quk@isham-research.demon.co.uk]
> Sent:	Wednesday, October 06, 1999 1:39 PM
> To:	kirby.a.smith@lmco.com
> Cc:	quattro@audifans.com
> Subject:	Re: re  Re: Ceramic coating EM's - II
> 
> In message
> <A955A4BCA8F8D011AE1C0000F804A88A0413C6C5@emss05m02.sanders.lmco.com>
> "Smith, Kirby A" writes:
> 
> >> No, it converts kinetic energy into heat.  The fact that exhaust gas
> >> is hot has nothing to do with it - it would be just as happy with
> >> cold gas input.
> >
> > Hmmm Phil, I'm not sure I would embrace this perspective.  Your first
> > sentence is literally true over the entire system.  The exhaust kinetic
> > energy is used to perform work on the exhaust turbine (which is attached
> to
> > the intake side compressor of course, pressurizing the intake manifold
> and
> > in the process generating heat).  If the gas kinetic energy is partially
> > used, the temperature of the gas will fall for that reason, as well as
> due
> > to the drop from any pressure fall across the turbine.
> 
> Kinetic energy is mass times velocity.  Mass cannot be altered outside
> of nuclear reactors - only velocity is available.  The blades are spun
> effectively by pressure - a differential between the manifold and the
> downpipe.  Heat has absolutely nothing to do with turbine operation -
> it's just a way of expanding the volume of an available gas to make it
> do physical work.  Once combustion is complete, the temperature of the
> gas starts to fall - to the point where you can put your hand in the
> tailpipe stream.
> 
> Heat is a form of potential energy, but there's no way of using it in
> a turbine.  In such a device, it's merely a nuisance.
> 
> > I do not believe your second sentence agrees with my understanding of
> turbos
> > from books I have read.  I believe the shape of turbines, whether jet
> engine
> > or in turbosuperchargers, is designed to use both flow and temperature.
> > This may all be semantic, as heat is kinetic energy in a gas.  The
> kinetic
> > energy is both random and directional, and both may be used in a heat
> > engine.
> 
> What physical effect exploits the temperature of the gas?  No water is
> boiled to make steam.  The effects are purely physical - the exertion
> of pressure against the blades.
> 
> --
>  Phil Payne
>  UK Audi quattro Owners Club
>  Phone: 07785 302803   Fax: 0870 0883933