Excitation force on a pump-jet propeller: The effect of the blade number

Abstract

This study investigates the influence of blade number on the propulsion performance and excitation force of pump-jet propellers (PJPs) using computational fluid dynamics. The primary objective is to determine the optimal blade number arrangement for reducing the excitation force of PJPs while operating behind a submarine. The numerical simulation method used is validated, employing the Reynolds-averaged Navier–Stokes method based on the Shear Stress Transport turbulence model to solve the turbulent flow problem, and the equation is discretized using the finite volume method. By comparing and analyzing the spectrum, it was found that the blade number would affect the unsteady force of single blades in six aspects, and when it impacts the Key Frequency,the amplitude of the excitation force varies dramatically. Through harmonic analysis and strip analysis, this study uncovers the influential mechanism of the blade number on excitation force. Additionally, a unique wake mechanism arising from the combined effect of stator and rudder is discovered by examining various number of stator blade and rudder. Ultimately, the optimal blade number of stator-rotor configurations is found to be 15 and 10, respectively. This study has implications for the design of PJPs with low excitation.