Pumps & pump power worksheet with answers

A pump raises the pressure of 20 L/s of water by 200 kPa. Inlet and outlet are at the same height and have the same diameter. Find the hydraulic power P_h in kW.

A pump delivers 50 L/s of water (ρ = 1000 kg/m³) and gives it a hydraulic power of 2.2 kW. Use g = 9.81 m/s². Find the head H the pump adds.

A pump with an efficiency of 75% delivers 30 L/s of water (ρ = 1000 kg/m³) against a head of 60 m. Use g = 9.81 m/s². Find the shaft power P_shaft needed, in kW.

A pump delivers 100 L/s of water (ρ = 1000 kg/m³) against a head of 80 m. The pump efficiency is 82% and the electric motor driving it has an efficiency of 88%. Use g = 9.81 m/s². Find the electrical power P_el the motor draws, in kW.

A pump moves 120 L/s of water (ρ = 1000 kg/m³) from an open lower reservoir to an upper tank whose water surface is 9 m higher. The pipe is 100 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 = 2 (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 100 kPa. Find the head H the pump must add.

A pump moves 20 L/s of water (ρ = 1000 kg/m³) from an open lower reservoir to an upper tank whose water surface is 15 m higher. The pipe is 200 m long with an inside diameter of 100 mm and a Darcy friction factor f = 0.02; the minor-loss coefficients add up to ΣK = 5 (entrance and exit included). Use g = 9.81 m/s². The pump efficiency is 65%. Find the shaft power P_shaft in kW.