6. A 6 250 m long, 914 mm (inside diameter) cast iron pipeline connects an upstream reservoir (water surface elevation 521.3 m) to a downstream reservoir (water surface elevation 512.3 m). A discharge valve at the downstream end is used to control flow; when this valve is fully open, the measured discharge in the pipeline is 840 L/s under the naturally available head difference. (a) Assuming fully developed turbulent flow and that all other local losses are negligible, estimate the loss coefficient k for the fully open valve. (b) Because of increasing urban development, the flow under the natural head difference is considered to be inadequate and it is proposed to increase this flow with pumping. The head-capacity curve for the pump can be approximated by the equation H = 8 – 3.5Q2 in which H is the total dynamic head on the pump (in m) and Q is the discharge (in m3/s). What is the discharge that can now be obtained from the system where the pump is installed at a cross-section of the pipeline?
6. A 6 250 m long, 914 mm (inside diameter) cast iron pipeline connects an upstream reservoir (water surface elevation 521.3 m) to a downstream reservoir (water surface elevation 512.3 m). A discharge valve at the downstream end is used to control flow; when this valve is fully open, the measured discharge in the pipeline is 840 L/s under the naturally available head difference.
(a) Assuming fully developed turbulent flow and that all other local losses are negligible, estimate the loss coefficient k for the fully open valve.
(b) Because of increasing urban development, the flow under the natural head difference is considered to be inadequate and it is proposed to increase this flow with pumping. The head-capacity curve for the
pump can be approximated by the equation H = 8 – 3.5Q2 in which H is the total dynamic head on the pump (in m) and Q is the discharge (in m3/s). What is the discharge that can now be obtained from the system where the pump is installed at a cross-section of the pipeline?
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