Here is some other food for thought once we can get a reading.
The signal output from the sensor (or magnetic nut retaining the
compressor wheel on the shaft) is recorded and fed back across the Y-Y
terminals of an X-Y oscilloscope. With a known frequency applied across
the X-X axis, the resulting output produces the phenomenon known as
Lissajous figures. By altering the frequency and phase of the X-X input,
a point will be reached when a perfect circle is produced on the screen,
and at this point the known frequency will be the same as that on the
Y-Y plates but 90ยบ out of phase, and hence the precise burst speed will
be known, compared with only the average over the timing interval by the
other method.
Can this be done in software?
-------- Original Message --------
Subject: [AR] Re: Turbopump prime mover
From: "Monroe L. King Jr." <monroe@xxxxxxxxxxxxxxxxxx>
Date: Sun, December 06, 2015 4:07 am
To: arocket@xxxxxxxxxxxxx
As it is now there will be hot gasses surrounding the turbine impeller
and liquid flowing over the pump impeller (water at first).
I can run the turbine initially with a substitute for the pump that can
make measurements easily.
But getting measurements with the pump installed is another matter.
I can not drill the turbo center section to mill the shaft in that area
because there is not a dry space to do so. I would have to do that by
designing that into the pump housing.
I am going to continue as if we will discover a better way to do it.
RPM's can get as high as 200,000 I'd like to be able to get readings to
that level.
I intend to put a butterfly valve in the exhaust to bypass the turbo and
be able to control flow to the turbine. To use the kinetic dyno I need
to be able to slam shut the bypass and accelerate the turbine as rapidly
as possible to the target RPM. Then maintain flow for use under load for
actual testing.
So getting RPM is a very key factor.
-------- Original Message --------
Subject: [AR] Re: Turbopump prime mover
From: "Nelson, Erik - 2" <erik.l.nelson@xxxxxxxxxxxxxxxxx>
Date: Sat, December 05, 2015 6:20 pm
To: "arocket@xxxxxxxxxxxxx" <arocket@xxxxxxxxxxxxx>
You might not need to mill a flat. If you can see the impeller and it's
shiny enough you might be able to get a usable signal with something like
one of these.
http://www.amazon.com/CyberTech-Digital-Photo-Tachometer-Contact/dp/B001N4QY66
-----Original Message-----
From: arocket-bounce@xxxxxxxxxxxxx [mailto:arocket-bounce@xxxxxxxxxxxxx] On
Behalf Of Monroe L. King Jr.
Sent: Saturday, December 05, 2015 5:51 PM
To: arocket@xxxxxxxxxxxxx
Subject: [AR] Re: Turbopump prime mover
Thanks for the reply Robert I believe I could do that if I drilled down to
the shaft threw the casing and milled a small round flat on the shaft to
reflect the laser.
The turbine it's self is a Inconel alloy and the pump impeller is SS so
that rules out magnetism on those parts.
Other ideas? Criticism welcome as well.
-------- Original Message --------
Subject: [AR] Re: Turbopump prime mover
From: Robert Steinke <robert.steinke@xxxxxxxxx>
Date: Sat, December 05, 2015 2:50 pm
To: arocket@xxxxxxxxxxxxx
Could you use a laser non-contact tachometer? It shines a laser on
your rotating part and counts the number of times a piece of
reflective tape goes by. I can't visualize your setup so maybe this
isn't useful because the problem is you can't see the rotating part,
but if you can see it, but not touch it this would be a solution.
On Sat, Dec 5, 2015 at 5:36 AM, Monroe L. King Jr. <
monroe@xxxxxxxxxxxxxxxxxx> wrote:
Ok I have a cart for the test engine, now I have to visit the local
junkyard for a useful engine I can rebuild. I believe we can make a
setup similar to this https://www.youtube.com/watch?v=vIzAfwPl3a0 to
make changing turbines/pumps out easier I think we will only need 3
different turbochargers S,M,L so we wont need more than 3 adapters.
Once I get the test engine ready I'll take the cart to a muffler
shop and get the exhaust tubing bent for the test stand.
That flow bench is neeto but it wont supply enough air for load testing.
The only problem now is I have to come up with a new way to get
turbine RPM readings. With cold flow I could get the reading of the
turbine side but now that's not going to be possible and the pump
will be on the cold side. Normally they take the readings off the
cold side put our pump will be in the way.
Any ideas on how to get the RPM readings?
To me this looks like the easiest way to get RPM and HP we need to
test pumps.
Comments?
-------- Original Message --------
Subject: [AR] Re: Turbopump prime mover
From: Ed LeBouthillier <codemonky@xxxxxxxxxxxxx>
Date: Thu, December 03, 2015 1:50 pm
To: arocket@xxxxxxxxxxxxx
over
The main reason I don't want to use a combustion/turbine such as
the ones made from turbochargers.
If your using the compressor/turbine you have to go turboshaft
and I've played with one of these combustion/turbines and they
are far from reliable.
Well to get upwards of 30 HP, you're going to need to come up with
something original.
There was a fella by the name of Nye I corresponded with while he
was developing one of the first of these (back in the 90's) and
they just don't run very well nor are they reliable enough.
Probably true.
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