Influence of the Blade Design Parameters on Hydraulic Noise Generation by a Low Specific Speed Radial Pump With Narrow Channel Flow

Present work aims to investigate the hydro acoustic behavior of a typical low specific speed radial type centrifugal pump with narrow channel impeller passage. The blade design parameters play an important role in hydraulic noise generation by a low specific speed radial pump with narrow impeller channels. Though, these pumps are hydraulically efficient for a given design point, the hydraulic noise production may be higher at duty point. The blade passage length along with the outlet width of the impeller are the two main design parameters of a radial impeller with narrow channels, which can impact the flow quality along the impeller blade passage. To understand the effect of the narrow channel, initially steady state simulation is conducted to predict and validate the hydraulic performance. Then transient simulations were conducted using Detached Eddy Simulation (DES) using STAR-CCM+ to predict the hydro acoustic behavior of the pump in terms of pressure fluctuations and far field noise spectra of the pump at specific points. The velocity profiles along the impeller channels, shows the formation of wake region, which strongly affects the jet wake flow phenomenon near impeller trailing edge. This results in high pressure fluctuations near impeller outlet.