Pumps & pump power worksheet with answers

A pump delivers 12 L/s of water (ρ = 1000 kg/m³) against a total head of 72 m. Use g = 9.81 m/s². Find the hydraulic power P_h given to the water, in kW.

A pump raises the pressure of 5 L/s of water by 400 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 40 L/s of water (ρ = 1000 kg/m³) against a head of 56 m. The pump efficiency is 70% and the electric motor driving it has an efficiency of 92%. Use g = 9.81 m/s². Find the electrical power P_el the motor draws, in kW.

In a test, a pump delivers 25 L/s of water (ρ = 1000 kg/m³) against a head of 68 m while its shaft takes 20.8 kW. Use g = 9.81 m/s². Find the pump efficiency η in percent.

A pump moves 50 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 400 m long with an inside diameter of 150 mm and a Darcy friction factor f = 0.022; the minor-loss coefficients add up to ΣK = 8 (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 200 kPa. Find the head H the pump must add.

A pump moves 40 L/s of water (ρ = 1000 kg/m³) from an open lower reservoir to an upper tank whose water surface is 21 m higher. The pipe is 300 m long with an inside diameter of 150 mm and a Darcy friction factor f = 0.025; the minor-loss coefficients add up to ΣK = 8 (entrance and exit included). Use g = 9.81 m/s². The pump efficiency is 82%. Find the shaft power P_shaft in kW.