184
A. Constantin and C. St. Nitescu
In the last decade, many efforts were made to rehabilitate and upgrade part of the
existing pumping stations, according to the new technological progress.
The engineering design for the rehabilitation of an existing pumping station aims
not only the meeting of technical required parameters but also the entire possible
energy efficiency during pumping station operation. Thus, every single variant of an
old pumping station modernization must be technically and economically analysed
before adopt a specific solution and the best method is a numerical simulation by the
help of a hydraulic software.
5.3.2.1 Base Irrigation Water Supply Pumping Station Mircea Vod˘ a
Mircea Vod˘ a pumping station is a valuable example for the base irrigation water
supply pumping stations. It operates in the irrigation system Carasu, in Dobrogea
and it is located on the left side of the Danube- Black Sea Canal. Water is taken from
the canal CA 0 by 14 identical electric pumps, of split case type. The impeller of each
centrifugal pump is of 950 mm in diameter. The pumps are connected in two groups,
and each group, composed of 6 + 1 pumps operating in parallel, delivers water on
its own discharge duct. The individual suction ducts are 1200 mm in diameter. The
water is transported by two mains of 1150 m in length and 1900 mm in diameter. A
horizontal air chamber of 30 m
3 total volume protects each main from water hammer.
One pump has a discharge of 6480 m
3 /h, at the total head of 65 m and operates at
the constant rotational speed of 750 rot/min. The driving electric motor of 1600 kW,
is powered by a voltage of 6 kV. The pumps did not work properly on all their
operation range determined by the static head variation of the system. The pump
operation had to be limited within the range 65–61.5 m due to the high value of the
net positive suction head, (NPSH). Moreover, the pumping station recorded a low
energetic efficiency. Therefore its modernization was needed.
The static head values, determined by the water level variation in the suction and
respectively, discharge basin, are H g max = 52.00 m; Hg med = 50.00 m; H g min =
48.50 m. These data and the total head losses all over the hydraulic system, which
were calculated taking into account the fully developed turbulent flow regime [4],
led to the following main values for the total pumping head: H max = 65.00 m; H med
= 59.80 m; H min = 56.00 m.
By a thorough analysis of the operation of the pumps and the customer’s demand,
we concluded that the pumps have to be renewed by ones with larger impellers, of
1000 mm in diameter. There were considered similar centrifugal pumps, with the
discharge of Q = 6500 m
3 /h at a total head of H = 65 m, with the same geometric
features, but with better inner hydraulics, which means efficiency of η = 90%. The
net positive suction head is NPSH = 8.5 m at the above given duty point [4]. The
electromotor power, the pump’s suction and discharge diameter are the same for
both the original and the proposed pumps. The new pumps run in the same range of
total head, but at higher discharge values, due to the larger impellers, that means in
between H min = 56 m (at Q = 7560 m
3 /h) and H max = 65 m (at Q = 6500 m
3 /h), at
a constant speed. The pump’s efficiency, at the maximum head H max = 65 m, is η p
A. Constantin and C. St. Nitescu
In the last decade, many efforts were made to rehabilitate and upgrade part of the
existing pumping stations, according to the new technological progress.
The engineering design for the rehabilitation of an existing pumping station aims
not only the meeting of technical required parameters but also the entire possible
energy efficiency during pumping station operation. Thus, every single variant of an
old pumping station modernization must be technically and economically analysed
before adopt a specific solution and the best method is a numerical simulation by the
help of a hydraulic software.
5.3.2.1 Base Irrigation Water Supply Pumping Station Mircea Vod˘ a
Mircea Vod˘ a pumping station is a valuable example for the base irrigation water
supply pumping stations. It operates in the irrigation system Carasu, in Dobrogea
and it is located on the left side of the Danube- Black Sea Canal. Water is taken from
the canal CA 0 by 14 identical electric pumps, of split case type. The impeller of each
centrifugal pump is of 950 mm in diameter. The pumps are connected in two groups,
and each group, composed of 6 + 1 pumps operating in parallel, delivers water on
its own discharge duct. The individual suction ducts are 1200 mm in diameter. The
water is transported by two mains of 1150 m in length and 1900 mm in diameter. A
horizontal air chamber of 30 m
3 total volume protects each main from water hammer.
One pump has a discharge of 6480 m
3 /h, at the total head of 65 m and operates at
the constant rotational speed of 750 rot/min. The driving electric motor of 1600 kW,
is powered by a voltage of 6 kV. The pumps did not work properly on all their
operation range determined by the static head variation of the system. The pump
operation had to be limited within the range 65–61.5 m due to the high value of the
net positive suction head, (NPSH). Moreover, the pumping station recorded a low
energetic efficiency. Therefore its modernization was needed.
The static head values, determined by the water level variation in the suction and
respectively, discharge basin, are H g max = 52.00 m; Hg med = 50.00 m; H g min =
48.50 m. These data and the total head losses all over the hydraulic system, which
were calculated taking into account the fully developed turbulent flow regime [4],
led to the following main values for the total pumping head: H max = 65.00 m; H med
= 59.80 m; H min = 56.00 m.
By a thorough analysis of the operation of the pumps and the customer’s demand,
we concluded that the pumps have to be renewed by ones with larger impellers, of
1000 mm in diameter. There were considered similar centrifugal pumps, with the
discharge of Q = 6500 m
3 /h at a total head of H = 65 m, with the same geometric
features, but with better inner hydraulics, which means efficiency of η = 90%. The
net positive suction head is NPSH = 8.5 m at the above given duty point [4]. The
electromotor power, the pump’s suction and discharge diameter are the same for
both the original and the proposed pumps. The new pumps run in the same range of
total head, but at higher discharge values, due to the larger impellers, that means in
between H min = 56 m (at Q = 7560 m
3 /h) and H max = 65 m (at Q = 6500 m
3 /h), at
a constant speed. The pump’s efficiency, at the maximum head H max = 65 m, is η p