Pumps & pump power worksheet with answers

A pump raises the pressure of 40 L/s of water by 750 kPa. Inlet and outlet are at the same height and have the same diameter. Find the hydraulic power P_h in kW.

A pump raises the pressure of 12 L/s of water by 350 kPa. Inlet and outlet are at the same height and have the same diameter. Find the hydraulic power P_h in kW.

A pump with an efficiency of 80% delivers 10 L/s of water (ρ = 1000 kg/m³) against a head of 70 m. Use g = 9.81 m/s². Find the shaft power P_shaft needed, in kW.

A pump delivers 50 L/s of water (ρ = 1000 kg/m³) against a head of 58 m. The pump efficiency is 78% and the electric motor driving it has an efficiency of 95%. Use g = 9.81 m/s². Find the electrical power P_el the motor draws, in kW.

A pump moves 100 L/s of water (ρ = 1000 kg/m³) from an open lower reservoir to an upper tank whose water surface is 11 m higher. The pipe is 200 m long with an inside diameter of 250 mm and a Darcy friction factor f = 0.018; the minor-loss coefficients add up to ΣK = 8 (entrance and exit included). Use g = 9.81 m/s². The pump efficiency is 65%. Find the shaft power P_shaft in kW.

A pump moves 80 L/s of water (ρ = 1000 kg/m³) from an open lower reservoir to an upper tank whose water surface is 17 m higher. The pipe is 400 m long with an inside diameter of 200 mm and a Darcy friction factor f = 0.018; the minor-loss coefficients add up to ΣK = 5 (entrance and exit included). Use g = 9.81 m/s². The upper tank is closed and the air above its water is at a gauge pressure of 250 kPa. Find the head H the pump must add.