Paul Carey wrote:
Hi Douglas and Paul
In my discussions with Theo, the Neptune owner who sold me the
Power
Turbine, he could talk endlessly about the PT blade design and
material
specs, and from memory he called it a "bucket" design - the
blade
can
absorb
most of the exhaust gas energy under load (as in - connected to
the
engine).
You can see the attached photos of the blades, the angle of
attack
and
double wall. The wheel is driven clockwise in these photos.
I wonder how a turbocharger, designed to free rev with no load,
will
handle
being direct driven. Will the turbine be able to absorb enough
energy,
and
what will the gas path be doing?
Regards PC
Paul Carey LAME, MC
Aero Group Pty Ltd ACN 109 854 015
Aero Management - aviation consultants.
www.aeromanagement.com.au
(08) 9371 5205 0418 959 892
Vance W Jaqua wrote:
The turbine is probably a GE design - direct from the same family as
the
B17
turbochargers - axial flow - reaction blade shaping. When I was at
GE
Aircraft
Gas Turbine Division in the late 50's early 60's any turbine blade
was a
"bucket"
GE's first production turbofan was a rear fan with a turbine section
inboard
and the fan blade section outboard, and they called that blade a
"blucket"(blade bucket)
With the hot root there was real concern about seperation failure,
so
various
armor rings were designed "blucket catchers" -
To answer how the direct drive turbine will react - like an enormous
flywheel
Vance
Paul Carey wrote:
Hi Vance
Very interesting comments - amazing who one encounters on this forum.
Do you mind expanding on your comment: "To answer how the direct drive
turbine will react - like an enormous flywheel"
Paul
The turbocharger suitability was a general doubt, based on a hunch - no
research. If it has been done before - great, and will be interesting to
see
your results. I am a firm believer in the concept.
PC
I am going to jump in here. Yes if geared up. If not geared up no more so
than
a regular flywheel. However... much to my early surprise and a lot of
other people's
surprise the engine rotational inertia has little to do with AA fuel drag
racing acceleration
as the clutch is dropped while the engine is running at near max torque
RPM. If
anything a heavy flywheel will store energy which is released when the
clutch is
side stepped. I think Archie can fill us in on this far better than I.
I know my RX8 does far better in the 0-60 time if I drop the clutch at
7000 RPM.
Paul Lamar
The gearing is exactly what that reference was about, For dragsters or
airplanes this is not a major issue, but if you are using it for fuel
economy the up/down rpm changes in normal driving would provide
major stresses and very disconcerting operation to the driver. Even
the near constant rpm radial operation drove the inclusion of a
fluid coupling - Vance>
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