You just read about the fan curve and laws. Pumps are devices which operate in a similar manner. In the case of pumps, the fluid is an in-compressible one called ‘water’.

So, in centrifugal pumps the rotating motor imparts this energy to the impeller which in turn transfers this energy to the water and causes it to accelerate.

The volute surrounding the impeller transfers this velocity energy of the fluid to Pressure head and hence gives us the increase in pressure obtained in the pump discharge.