mag

Malaysia Water Research Journal
Figure 3. Water circulation system and scale model of the pump sump.
The assessment of the pump sump model test involved observing the
approach flow pattern towards each operating pump intake with the aid of a
blue dye tracer. This gave a good insight as to how the pumps would respond
since any flow that departs significantly from the one of the steady flow is
undesirable. This uneven distribution of flow approaching the pumps can cause
swirl and vortex formation at the pump intake.
2.1 Test scenarios
Tests were undertaken under steady conditions with each duty pump
operating at the specified design flow rate and water levels provided by client.
Using Froude Number similarity, the model flow capacity for each major pump
(P1 & P2) is 7.9 l/s and the capacity for minor pump (P3 & P4) is 4.74 l/s. The test
scenarios (please referred Table 2) in this study are as follows:
• A single pump, the P4 (minor pump) in operation at MSL +0.40 which is
equivalent to 260 mm from the bottom of the sump (minor pump)
• Two pumps, P4 (minor pump) and P1 (major pump) in operation at MSL +0.90
which is 310 mm from the bottom of the sump (minor and major pumps)
• Three pumps, P4 (minor pump), P1 (major pump) and P2 (major pump) in
operation at MSL +1.50 which is 370 mm from the bottom of the sump (minor
and major pumps)
• All pumps in operation at MSL +1.80 which is equivalent to 400 mm from the
bottom of the sump
Institut Penyelidikan Hidraulik Kebangsaan Malaysia (NAHRIM)
5
National Hydraulic Institute of Malaysia (NAHRIM)