Investigation in scale effects on propellers with different magnitude of skew by CFD methods

Abstract

Scale effects on the open-water performance of marine propellers are the problems to be investigated to the researchers and ship designers. Present thesis analyse the scale effects of marine propellers by CFD methods. The main focus is on the aspects related to propeller blade skews. The ambient flow around the propeller is assumed to be fully turbulent and the Reynolds-averaged Navier-Stokes (RANS) equations are applied in the turbulent flow. Propellers with different scales and skew angles operating in open-water conditions will be simulated in the CFD software – STAR-CCM+. The differences in open-water characteristics (e.g. thrust coefficient 𝐾𝑇 , torque coefficient 𝐾𝑄 and efficiency 𝜂0 ) of propellers with different skew angles are demonstrated and explained through the analysis of simulated flow patterns around the blades, as well as through the reasonable estimations of percentage of pressure and friction force contributions. The CFD results are compared with some experimental data for verifications.