You have the following data set from a pump that is operatin

You have the following data set from a pump that is operating at 1725 rpm with a 16 cm diameter
impeller:

To match your current system, you plan on changing both the impeller and the operating speed. What
impeller diameter and pump speed should you specify so that it will operate at its best efficiency point
with a pump head and a flow rate as close as possible to 15 m and 7.5 Lpm respectively? Assume the
best efficiency point for the pump at the conditions in the table occurs at a volumetric flow rate of 20
Lpm.

Solution

To match your current system, you plan on changing both the impeller and the operating speed. What
impeller diameter and pump speed should you specify so that it will operate at its best efficiency point
with a pump head and a flow rate as close as possible to 15 m and 7.5 Lpm respectively? Assume the
best efficiency point for the pump at the conditions in the table occurs at a volumetric flow rate of 20
Lpm.