Here is a picture of the test set up. It is a closed loop system
with a ball valve using 1-1/2 ID pipe through out.
Well as I suspected there are some significant differences in the
closed loop system compared to the open loop system.
Kind of blew me away when I saw 40 GPM on the flow
meter with a wide open valve at only 2000 pump RPM.
With the valve partial closed (fully closed is 90 degrees)
the flows are as follows.
25 GPM and 15 GPM at 2000 pump RPM's see the pictures below.
The flow is a very sensitive function of the total restriction
in the system. At low RPM's small increases in restriction will
generate rapid losses in total flow. Pressure increases are
minimal. The highest pressure I have seen on the outlet of
the pump so far is about 3 psi.
At 4200 pump RPM wide open it pegged the flow meter at well over 75 GPM.
I adjusted the valve partially closed for 75 GPM at 4200 pump RPM and the
30
amp 110 volt circuit breaker blew in about 30 seconds.
I need to borrow a more powerful mill. No doubt about it these pumps
suck the HP. The pump get quite warm on only a few seconds of running.
Paul Lamar
Paul - Now that is really what I would call a closed loop. I do not
understand
the pressure gage on the suction side, and how do you assure that you are
not running
mixed flow with entrained air. A supply tank would keep the temp rise a bit
more
under control for longer data taking runs. I have a 220 volt 2 hp 3600 rpm
motor
on a home made shaper table that you could borrow - but that might not
really
be any better - Vance
I am sure the pump whips up a froth but so too would a real system.
I know of no way of avoiding that.
As soon as the RTV pump gasket gets a chance to cure I will pressurize
the system and see if it makes any difference. I need to change out the lower
pressure gage for one that reads both positive and negative.
I think I need at least a 5 HP mill. There is one on the East end of SZP.
I am also planning on finding some plexi tubing and inserting it into
the loop on the intake side.
The heat is not a serious problem yet. I can still hold my hand on it.
Paul Lamar
The AirCraft Rotary Engine NewsLetter. Powered by Linux.
ACRE NL web site. http://home.earthlink.net/~rotaryeng/
Copyright 1998-2003 All world wide rights reserved.
