Research On Energy Saving Performance Of Propeller Boss Cap Fins And Additional Thrust Fins In Full Scale

Propeller boss cap fins (PBCF) and additional thrust fins are two frequently used energy saving devices back of the ship propeller. In almost past research, the study about the PBCF and trust fins are in model scale, however the sterm wake have great difference between the model scale ship and full scale ship. The study under the model scale cannot reflect the real result. This paper studies the performances of the PBCF and additional thrust fins both under model scale and full scale based on CFD. And the differences between them are talked and analysed.The performances of the propeller and propeller with PBCF are calculated under open water condition. The results are compared with experiment and the differences between propeller and propeller with PBCF are talked.The wake flow of the ship in both model scale and full scale are simulated. The mean axial velocity distributions in the ship stern are compared. The result shows that the flow under full scale has thinner boundary layer and higher axial velocity.The propulsion performance in both model scale and full scale are calculated in which the wave making is ignored, the influence of the PBCF and additional thrust fins are also analysed. The result shows that the delivered power dropped about 2% with the those devices.The difference of the flow characteristic in the propulsion between model scale and full scale are talked, and difference of working state of the energy saving devices between model scale and full scale are also analysed.