الفهرس 
REVIEW OF PREVIOUS WORK
THE TEST RlG AND THE EXPERlMENTALOnly 14 pages are availabe for public view
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Abstract
e present work is concerned with the investigation of the effect of some
parameters on the performance of the water ring vacuum pump. Namely, these
parameters are; eccentricity ratio (the ratio between eccentricity and casing
inner diameter), the number of impeller blades and the impeller rotational
speed.
A test rig was designed and constructed in a way suitable to measure the
necessary independent parameters required for the study.
A special pump was designed and manufactured. The body of the pump is
constructed from three different parts; two covers and a casing. Five different
casing were manufactured to change the eccentricity ratio. Also, five impellers
with different number of blades were manufactured. One of the above
mentioned impellers (having 16 blades) is tested with the five different
casings, whi1e the casing resulting in the maximum eccentricity is tested using
the other four impellers. All tests were carried out at three different rotational
speeds.
The tests data were used to draw the pump characteristics. It was found that:
1) The performance characteristics of water ring vacuum pump show a
mark dependence on the vacuum percentage developed by the pump.
2) The tests insured the remarkable effect of rotational speed variation on
the pump performance. As the speed increases, suction capacity,
vacuum percentage and brake power increase.
3) The eccentricity ratio has a great effect on water ring vacuum pump
performance. Within the tested range, increasing this ratio, improves the
pump performance that means to increase suction capacity and vacuum
percentage.
) Increasing number of impeller blades had also a noticeable effect on
pump performance. As the number of impeller blades increases, suction
capacity and vacuum percentage increase reaching a maximum value at
a certain number of blades, after which these values begin to decrease
with increasing the number of blades. The highest value of the
maximum vacuum percentage occurs at higher number of blades as the
rotational speed decreases, while the highest values of suction capacity
occur approximately at the same number of blades (twenty) for all the
rotational speeds.
5) It is noticed that at low vacuum percentage, the brake power consumed
by the pump, having an eccentricity of 15mm, is higher than that of any
other model. As the vacuum percentage gets higher than a certain value
(around 0.3), the brake power becomes less than those of model 3 and
model