Partload regimes of all types of centrifugal pumps are strongly and unfavorably affected by an influence of an inlet recirculation. This negative phenomenon usually occurs at pump suctions, when a circumferential velocity component of the fluid flow (derived from a rotational speed of a rotor) is dominant over an axial velocity component. Such physical effect goes hand in hand with a creation of a pump-head instability, a decrease of an overall efficiency, an excessive noise and pressure pulsations and even a possible cavitation formation. The introduced technical problem was tested/examined for a radial centrifugal pump Ns375 with a volute (spiral casing) and an axial intake domain with two potential countermeasures. Both, a physical experiment and transient numerical simulations were employed and compared on crucial levels.
Science Journal 