Design Method and Profile Optimization of Energy Saving Shaft Strut

The working mechanism, design method and profile optimization of energy saving shaft strut (ESSS) are present in this paper. The working mechanism of the ESSS is similar to the fixed guide vane (FGV) in front of the propeller, and the design of the ESSS must be simplified compared with the FGV, but the requirement of the shaft strut itself must be satisfied. The location and orientation of the struts and its energy saving effectiveness obtained in ship model experiments are present in detail in the paper as well. It is shown that the pre swirl action would be enhanced with the convergence angle being about 10° of the two struts of the shaft, and the energy saving effect of the ESSS may be enhanced to about 12%. The cavitation experiment of the ESSS and propeller exciting vibration measurement show that the optimization is successful of the profile of the ESSS with the high lift to drag ratio hydrofoil, which is achieved by combining the potential theory of the Eppler′s wing section design method with the analysis for the fluid field by solving N S equation. In this way the resistance of the ESSS would be reduced effectively and the inception of the cavitation would be delayed significantly. Thus the ESSS may be applied to the highspeed ship rapidly. The sea trail show that the design of the ESSS is successful.