I do know that the turbine inlet is @2.5 inches and the pressure is
around 60 psi when the turbine is at full power. The inlet temperature
is high at 600-800 degrees.
This turbo came off a 3L engine or 183 CID so every 2 revolutions at
100% efficiency 183 cubic inches is the most it can flow.
-------- Original Message --------
Subject: [AR] Re: Turbopump prime mover
From: Ed LeBouthillier <codemonky@xxxxxxxxxxxxx>
Date: Thu, December 03, 2015 8:44 am
To: arocket@xxxxxxxxxxxxx, arocket@xxxxxxxxxxxxx
Well I can do the engine/compressor if I need too.
the flow rate should be roughly 30 pounds per minute.
Well, just do the math to see how big the tank has to be.
How many seconds do you want to be able to run the turbine?
Total lbs = pounds_per_second * seconds
At 100 PSI, air has a density of 0.585 lbs/cuft
[http://www.engineeringtoolbox.com/air-temperature-pressure-density-d_771.html]
For 5 seconds of pressure, you'll need:
30 #/s * 5 s = 150 lbs
Given:
Density = weight/volume
Volume = weight/Density
Volume = 150#/0.585 #/cuft
Volume = 256-ish cuft @ 100 PSI
I guess I'll just start with 1/4" flare fittings 4 of them and tap them
for orifices so I can just drill them out as we go.
I think you need to think the overall problem out more.
Look at the volume figures above, if you want to feed your turbine for 5
seconds, you'll be flowing 256 cuft / 5 seconds = 51.2 cuft per second
through your plumbing. If you're using 1/4 inch fittings, then the length
that the volume travels per second will be 150197 feet (length = volume/area).
That's far above sonic velocity. 1/4 inch fittings won't cut it.
I think someone here suggested that you should have something on the order
of flow rate of 3 meters/second [~10 feet/second] through plumbing. Given
the 51.2 cuft per second volumetric flow rate, you'll need a pipe diameter
on the order of 2.5 feet diameter. Let's look at some other possibilities:
Gas
Lineal
Velocity Diameter
(ft/s) (in)
---------------------------
10 30.7
20 21.7
50 13.7
100 9.7
200 6.9
500 4.3
1000 3.1
So, that kind of pressure, density and
mass flow rate suggest that 1/4" fittings
aren't going to cut it.
In point of fact, you won't be able to sustain
the pressure at anything near reasonable mass/volumetric
flow rates. So, your performance will be even less.
I'll start off with my shop compressor and move up to my torch regulator
for higher pressure.
I need to set up the dyno for testing anyway and I can start off that at
lower output.
I'll get the best angle freehand by holding the nozzle in hand and
trying it on the turbine.
that's cool. But you wont' get 30 HP out of that. More likely,
you'll get millihorsepower. I've done the math on this kind of
setup and that's the kind of numbers that I get.
Again, I'm just going off the top of my head so I may have
made massive errors in the above calculation. But, these
order of magnitude numbers seem to be what I recall are
right.