A particular mixed flow pump is operating just below the point of cavitation. The pump is sited with its intake 3 m above the water level in the reservoir and delivers 0.05 m3/s. The total head at the inlet to the pump is -7 m. (Atmospheric pressure is 101.4 kN/m2 and vapour pressure is 1.82 kN/m2.)
An identical pump is to be installed at a higher reservoir, where the atmospheric pressure is 93.4 kN/m2 and vapour pressure is 1.2 kN/m2. It will be required to operate at the same discharge and head. What is the maximum height the pump can be installed above the water level to ensure cavitation free operation?