Mechanical efficiency of a centrifugal pump is the ratio of

Q. Power required to drive a centrifugal pump is directly proportional to __________ of its impeller.

Q. In a power plant, water density $(\rho =1000kg/m^3$) is pumped from $80kPa$ to $3MPa$. The pump has an isentropic efficiency of $0.85$. assuming that the temperature of the water remains the same, the specific work (in $kJ/kg$) supplied to the pump is

Q. The inlet and the outlet conditions of steam for an adiabatic steam turbine are as indicated in the notations are as usually followed.

Assume the above turbine to be part of a simple Rankine cycle. The density of water at the inlet to the pump is $1000kg/m^3$. Ignoring kinetic and potential energy effects. the specific work (in kJ/kg) supplied to the pump is

Q. Consider the following statements in context with centrifugual pumps :
1. Head developed is proportional to square of the speed of rotor.
2. Backward curved blade impellers are generally used in centrifugal pumps.
3. These pumps generally do require priming.
4. Multistage pumps would give higher discharge proportional to the number of stages.
Which of these statements are correct ?

Q. A centrifugal pump is to discharge $7.08m^3$/min at a speed of 1450 rpm against a head of 25 m. The impeller outlet diameter is 25 cm, its width at outlet is 5 cm and manometric efficiency is 75%. The vane angle at outer periphery of impeller is: