ABSTRACT
Centrifugal pumps are used in the majority of all fluid flow processes. The flows in both stationary and rotating internal flow passages of centrifugal pumps are quite complicated. Even when operating at the best efficiency point (BEP) 100" design flow, centrifugal pump internal flow fields are somewhat unsteady. Centrifugal pumps are closely related to hydro turbines, the fundamental distinction being that in turbines mechanical energy is extracted from the fluid, whereas in pumps mechanical energy is transferred to the fluid. The contrasting differences between pump impeller geometry and turbine impeller geometry clearly reflect this fundamental difference between diffusers and nozzles. Realizing the basic differences between nozzles and diffusers, one can also appreciate the well-known fact that a typical-high efficiency centrifugal pump impeller can be a fairly efficient turbine impeller. Conversely, a typical high efficiency turbine impeller will make a quite inefficient centrifugal pump impeller.
