March 6 - 8, 2017 | Berlin
LEADING ENGINEERING SIMULATION CONFERENCE
The ever ongoing quest for more efficient propulsion in the marine sector leads to the development and improvement of energy saving devices such as a pre-swirl stator. Wärtsila has joined this quest to lower fuel consumption will reduce operating costs and emissions. The targeted market segments are bulk carriers and container ships.
The complex flow and interactions are investigated by means of CFD with STAR-CCM+®. The pre-swirl stator is positioned upstream of the propeller and act as a wakefield modifier. The target is to alter the tangential velocities at the propeller plane to a favorable inflow for the propeller with as less a possible resistance increase.
A method has been setup to predict the power reduction when introducing a pre-swirl stator by means of a numerical self-propulsion calculations and analyze the flow phenomena. The CFD simulations consisted of transient RANS moving mesh calculations using a free surface with a full scale geometry. The entire ship geometry is included, i.e. hull, propeller, rudder and stator fins. For the stator fins geometry a parametric model was used, where e.g. pitch, rake, camber and chord length can be varied.
By analyzing and adjusting several designs Wärtsilä was able to better understand the occurring interaction effects and design the best stator fins for the investigated case.