[Diy_efi] Seen one, want LOTS more !!

[Oolan Zimmer]

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At 03:11 AM 1/10/2003 -0500, you wrote:

>Crap, I thought you had all the answers ;) I've always wondered about
>turbine maps, you can find some charts in Garrett's new catalog,
>http://www.turbobygarrett.com/turbobygarrett/jsp/index.jsp I'm not sure how
>to read them, but I'm guessing Oolan's links will help.

Thanks, Grant!

In the catalog from the link above, Garrett has made some samples of 
turbine maps and compressor maps available for their new GT-series 
turbos.  It's only one of the graphs Greg wanted, but at least some of the 
info is out there and easy to get to.  BTW, I notice that even their 
smaller turbo combinations have huge turbine A/R's but decently broad 
maps.  How'd they do that?

I took the time to read the thesis I posted the link to last night, it's 
point is that turbine maps aren't as useful a design tool for automobiles 
as one would think.  The turbine maps are generated from steady-state 
conditions, while in a real engine the turbine is hit with (possibly 
supersonic) pulses from individual cylinder discharges.  This can result in 
quite different behavior than the steady state tests would imply.  He 
proposed some alternative models for understanding turbine behavior when 
attached to an internal combustion engine.

As I understand it, turbines in turbojet engines see closer to steady-state 
conditions, and steam turbines in power plants see steady state 
conditions.  The turbine maps are all you need for a power plant, and a 
turbine and compressor map should be enough to design a single-stage turbojet.

Oolan Zimmer
o_zimmer at soltec.net


 > Santa wife, who is a librarian the rest of the year, managed to get me a
> > copy of the (out of print) Humphries book "Automotive Supercharging and
> > Turbocharging Systems" (Motorbooks)
> >
> > GREAT book, best one I've ever come across on the subject, including
> > McInnes and Bell.
> >
> > Long story short, on page 112 (bottom left) is a TURBINE MAP, credited to
> > Garrett and said to be for a TO-25 turbine. Essentially, it consists of
>two
> > graphs -- one is Turbine Pressure Ratio vs. Turbine Efficiency, the other
> > is Turbine Pressure Ratio vs. Corrected Turbine Mass Flow (in lbs./min.).
> > In this particular case, because the TO-25 has an integral waste gate,
> > there are five lines on each of the two graphs--each line for different
> > waste gate positions between 0.0" (closed) and 0.4" (wide open).
> >
> > The main point is that THIS DATA EXISTS--- SOMEWHERE-- and quite likely
> > exists for every possible pairing of turbine wheel trim and exhaust
>housing
> > (each A/R housing and configuration--on center, tangential, or split--
> > should have a different curve, for each and every Garrett turbo !! In the
> > case of turbos without integral wastegates, there would only be one line
>on
> > each graph, BUT THAT'S ALL THAT WOULD BE NEEDED !
> >
> > My POINT is that THESE turbine curves are ALL of the rest (besides the
> > compressor maps) of the info needed (only other number needed is pre
> > turbine EGT !!) to do a full quantitative turbo match to an engine, rather
> > than doing it "by guess and by golly" !!
> >
> > SO--does _ANYBODY_ know where to find copies of the rest of these turbine
> > maps for Garrett (or any other mfgrs.) ???
> >
> > Thanks,
> >
> > Greg

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