Douglas Fir wrote:

Paul

 I must admit I was getting confused for awhile wondering if you are
speaking about auto or aircraft applications steam injections and model jet
engines:)

I read NACA report 786  report by the way. Thanks.  Very interesting that
this work was done in 1943.

Monty made some good points about large blow down turbines. It would be time
consuming to develop compared to playing with the tons of radial turbines on
the market or laying around the junk yards.

OK let me confirm this I should be looking for a Garrett T04 or T45 to
modify.

 Below is your post from a few weeks ago.

Had a long talk with my friend at Garret now Honeywell and
he gave me a few tips. Make sure you use a ceramic ball bearing turbo charger
and don't put any side load on the shaft itself. The biggest problem
they have is the whirl vibration mode of the shaft. The ceramic ball bearing
shaft systems are much stiffer and that problem goes away more or less.
He also confirmed the TO4 or the even larger T45 would be the right
starting point.

For 30 to 55K operational ranges?

He also gave me some contacts to get some turbine maps of flow verses
efficiency and pressure ratio for existing products. The A/R to use for a given
radius is not necessarily the highest. Turbine blade angle is
varied to optimize it for flow and pressure ratio. One turbine

[blade]?

design is used with a wide range or A/R housings to adjust the turbo charger

for

a given engine configuration. Therefore a change in the A/R makes small single
digit changes in the efficiency.

I realize I am going to have to test a lot of different housings and turbine
rotor design to optimize it.

What site can I go to get size, weight data?

And oh yes... Thanks for getting the book on ethanol production.  I would
love to see it.

Good news.  My brother says he may have found an old electric prop
controller and props from an 1950s era Bonanza.  He said I could trim them
down and use them for a C\S (manually operated) for testing the engine on
the dyno.  I also have a manual transmission on hand. One of the speeds
ratios is close to 1:1. Could I use this as a dyno unit PSRU?  I would
rather not stress out a new PSRU until the design components are finalized.

doug in Japan

I think you are being very optimistic on the 30 to 55K. It appears the rule
of thumb is the gas speed must be twice the blade speed.  I have not figured
it out yet but you can do it yourself by converting the 24 pounds per minute
mass flow to cubic feet per minute and then figure out what the scroll area of 
the TO4 turbine is. That is the easy part. Here it is. The turbine wheel diameter for a  
TO4 is either 2.992 or 3.111. As a first guess the the R in A/R is therefore 
about 2.5 inches. For an A/R of one that means the area of the scroll is 
also about 2.5 square inches. The part number for the .96 A/R TO4 turbine
housing is 407414-0021 trim O or 407414-0031 for trim P.

The question is;  what is the exhaust velocity of the gas passing down a 2.5 
square inch pipe when the mass flow is 24 pounds per minute and the temperature 
in absolute terms is 2000 degrees K? Once you know that you will know the RPM of 
the roughly 3 inch in diameter turbine. Check back in the earlier messages.
Vance thinks it is 440 feet per second but I am not so sure as we have data
from Francois showing a TO3 turbine rotating at 130,000 RPM and 440 feet
per second won't do that. I think the gas velocity is much higher than
that.

The transmission will work.
   
Paul Lamar
 
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