Application: Model testing to establish that the proposed pumping station layout and dimensions were adequate for both summer and winter operation

Site: Al-Shuaiba Pumping Station, Kuwait

Service: Physical Modelling

Problem: For winter operation, a minimum flow rate of 60,000 m³/hr and a maximum flow of 105,000 m³/hr was needed. Initially nine pumps with a flow capacity range of between 3.65m3/s to 5.50m3/s (run out) were proposed, with the option of installing one additional standby pump in the future. In winter, a maximum of eight pumps and one or two cooling towers would operate. For summer operation the station capacity would be a minimum flow rate of 75,000 m³/hr and a maximum of 105,000 m³/hr. Again a maximum of 8 pumps would operate, with flow entering through both of the cooling towers.

Objectives: To construct and test a 1:10 hydraulic scale model of the pumping station to demonstrate that the proposed pumping station layout, dimensions and operation were suitable for:
a. winter operation
b. summer operation.

Approach: A total of ten pumps were installed in the model arrangement and used in the test matrix. The test programme included the operation of the station when certain sections were isolated for maintenance purposes.

Outcome: Following extensive testing of the scaled hydraulic model, modifications to the initial design were proposed. These included:

• the installation of flow splitting vanes beneath each pump intake to suppress the excessive swirl or pre rotation of the intake flow
• vertical blades attached to the rear wall of the pump cells to further stabilise flow conditions at the pump intakes and sections of tapered benching positioned either side of the pump units to prevent the formation of submerged vortices

Flow conditions in the cooling tower outlet sumps at single tower operations were found to be very aerated at the minimum pump cell water surface elevations and high station flows. The aeration was seen to moderate as the water level rose above the minimum or when both towers were operating.

The model functionally demonstrated and optimised design, provided a comparison of design solution options, and facilitated performance observation and assessment by the project team.

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