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I did some EWP flow tests yesterday. I did not see as much flow from the WP337
as I was hoping to see. I've attached a graph which summarizes flow vs voltage
measurements, and a picture of the measurement setup. I need to get a couple
of pressure meters and a valve so that I can get flow vs pressure
measurements. The only number I was really interested in with these
measurements was the maximum flow. I generated the voltage vs flow
measurements because they might be useful (and I could). Pure water was used,
and the water temperature was 66 F. +/- a couple of degrees
NOTES:
1) First, the flow measurement doesn't reflect the potential of the pump. The
pump is designed for 1 1/2 inch input and two 1 inch output hoses. I'm using a
1 inch AN16 input and two 0.69 AN12 outputs. These are the sizes I will be
using in the installation. The flow meter also adds a restriction.
2) The WP337 has two AN12 outputs. The graph labled "One Out Flow" has one of
the AN12 output hoses blocked. The current readings and flow readings were
almost identical for the "One Out" measurements so the plots are superimposed.
The "Two Flow" plots are with both outputs at full flow.
3) On my earlier test, I had the flow meter on the output. Since I now have
two outputs, I moved the flow meter to the input. This causes a restriction on
the input which may have produced some cavatation on the highest flow reading.
The 15 Volt Two Flow reading was jumping between 14.5 and 15 GPM. I chose to
plot it at 14.8 GPM
4) I found that with the output tubes pouring water onto the surface of the
water in the container, enough air was introduced into the system to cause
unstable readings. I submerged the hoses and purged air from the flow guage by
holding it vertically. Then the readings were very stable (except as noted
above). The guage has a tendency to stick however and it was necessasry to tap
the guage to get a good reading.
5) Because of the guage sticking and the low resolution, especially at the
lower readings, I'm not sure if the kink at 9 V on the Two Flow graph is real.
I would expect the error bars to be about the size of the data point symbols,
maybe larger at the low end.
6) The data point for the WP136 is the only comparable number I had for that
pump. Other measurements were done as installed thru the engine and evap
cores. The flow was with 0.75 inch ID AN12 hoses for input and output.
Conclusions:
I'm dissapointed in the flow results. I would like to have seen more flow, but
I can't say for sure what the flow will be in the installation. I didn't have
a pressure meter to measure the static head pressure. Knowing that, I should
be able to relate the flow of this pump to the measured flow of the WP136.
It's possible that the flow meter is causing enough of a restriction to
significantly lower the readings. With a little effort, I can set up a test
where I time the flow from a large container into a smaller one.. That should
answer that question.
I got the Davies-Craig pump from Rusty yesterday. It really looks wimpy even
compared to the WP136. I will get some flow measurements on it next week. It
will be interesting to see how it looks on the same setup I'm using for the
Meziere pumps and how that compares to Todd's flow measurements.
Installing the WP337 will be a lot simpler than Installing two WP136's, so I
will go ahead with the installation and see what the cooling temps look like
once I get the engine running.
I also have some pictures comparing the sizes of the Meziere pumps and the
Mazda EDWP. I have uploaded them to the Wiki (go to http://www.rotarywiki.org
and expand the Image Gallery menu. Then open the Wiki Images gallery) but it
may be a couple of days before I can write up a wiki page.
Bob W.
--
http://www.bob-white.com
N93BD - Rotary Powered BD-4 (real soon)
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