Concept explainers
The geometry of a centrifugal water pump is r1 = 10 cm, r2 = 20 cm, b1 = b2 = 4 cm, β1 = 30°, β2 = 15°, and it runs at speed 1600 rpm. Estimate the discharge required for axial entry, the power generated in the water in watts, and the head produced.
The discharge required for axial entry, the power generated in the water in watts, and the head produced.
Explanation of Solution
Given:
Inlet impeller radius is
Outlet impeller radius is
Inlet blade angle is
Outlet blade angle is
Speed of the centrifugal water pump is
Inlet tangential velocity is
Impeller inlet width
Impeller outlet width
Calculation:
Calculate the angular speed of centrifugal water pump
Calculate the runner speed at inlet
Calculate the runner speed at outlet
Draw inlet and outlet velocity diagram as shown in Figure (1).
From Figure (1).
At inlet,
Calculate
Using continuity equation calculate the discharge required at the entry
Thus, the discharge required at the entry
At Outlet,
Calculate tangential velocity at outlet
Calculate the theoretical power generated in the water
Thus, the power generated in the water
Calculate the theoretical head
Thus, the theoretical head
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