Numerical analysis of the influence of brash ice on propeller performance with CFD-DEM method

Abstract

In this study, the influence of brash ice on propeller performance is numerically analyzed using the coupling method of Computational Fluid Dynamics (CFD) and Discrete Element Method (DEM). Among them, fluid part is modeled with CFD method, while DEM method is applied to model the brash ice and evaluate the ice-ice and ice-propeller interactions. Firstly, we carry out the numerical prediction of propeller performance under ice-free condition, and obtained efficiency coefficient corresponding to different advance coefficients, which show good agreement with experimental data. Subsequently, hydrodynamic performance of propeller in different ice-level sea areas is analyzed by gradually increasing the number of ice injectors in the calculation domain. The results show that when the content of brash ice is relatively limited, the flow characteristics around propeller is less affected, so propeller performance does not change significantly. With the increase of brash ice, the non-uniformity of flow field around the propeller rises rapidly, which leads to the fast deterioration of propeller performance. In the case with 12 DEM ice injectors, the thrust and torque coefficients increase about 10% and 6%, respectively.