Across a centrifugal pump, the increase in energy per unit mass of liquid is g delta h. where g is the gravitational acceleration and delta h is the increase in head. This quantity g delta h may be a function of the impeller diameter D. the rotational speed N, liquid density rho, and the flow rate Q A centrifugal pump operating at 2,000 rpm is to be designed to handle a liquid hydrocarbon of specific gravity 0.95. To predict its performance, a half-scale model is to be tested, operating at 750 rpm. pumping a light oil of specific gravity 0.80. The scale model is found to deliver 400 gpm with a head increase of 20 ft Assuming dynamical similarity, for the full-size pump Q = 8,533 gpm delta h = 569 ft