Abstract
The paper presents the analysis of results of
the investigations concerning a vertical pipe submersion
coefficient h/L with an air-water mixer of the described
type. The investigations were performed on an air lift
pump testing stand, constructed in a laboratory on a scale
of 1:1. At first, the paper presents the possibilities of
application of air lift pumps. The investigations to date
have been briefly characterized and a research problem
formulated. Then the paper describes the construction and
working principle of the air lift pump testing stand,
constructed in a laboratory. It presents the methodology
of derivation of empirical formulas for calculation of
vertical pipe submersion coefficients h/L. The
comparative analysis of the values of h/L determined in
the measurements with the values of h/L calculated using
the derived empirical formulas was carried out. The
research scope encompassed the derivation of the
aforementioned empirical formulas for five fixed values
of air lift pump delivery head H, comparison of the
obtained values h/L determined in the measurements with
the values of h/L calculated using the derived empirical
formulas and the improved analytical Stenning-Martin
model. To derive the empirical formulas for calculation of
the vertical pipe submersion coefficient h/L, the
dimensional analysis and multiple regression was applied.
The investigations of the vertical pipe submersion
coefficient h/L were carried out for the vertical pipe
internal diameter d = 0.04 m and for the fixed delivery
heads H: 0.45, 0.90, 1.35, 1.80, 2.25 m. The values
calculated using the derived empirical formulas (23), (24),
(25), (26), (27) coincide with the values of h/L determined
in the measurements for the whole range of the
investigated delivery heads H. On the other hand, the
values of h/L calculated using the improved analytical
Stenning-Martin model do not coincide with the values of
h/L determined in the measurements for the delivery
heads H equal 0.45 and 0.90 m, whereas they are
comparable for H equal 1.35, 1.80, 2.25 m. For the tested
air lift pump with the air-water mixer of the described
type (Fig. 2), the maximum air pressure should not exceed
pp = 145 kPa, because for higher pressures the water flow
rate diminishes. In the air lift pump being tested, the water
flow rate Qw grows along with the rise in the air flow rate
and in the vertical pipe submersion coefficient h/L
whereas falls along with the rise in the delivery head H.
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