Research On Hydrodynamic Performance Of Propeller Boss Cap Fins Based On Surface Panel Method

Nowadays,the ship energy saving technology is developing rapidly,and as a energy saving device which has simple structure,installation convenience and better energy saving effect,the propeller boss cap fins(PBCF)obtained the widespread attention and application.Although there are a lot of application examples,the research on PBCF is still in the majority with experiments.In this paper,the surface panel method is adopted to do the theoretical research of hydrodynamic performance of the Combination systems of propeller,PBCF and rudder,then the energy saving effect and mechanism of PBCF are analyzed.At the same time,four main parameters of PBCF is selected as the parameter optimization.In this paper,the programs based on surface panel method of open-water propeller steady hydrodynamic performance prediction and the programs based on surface panel method of direct solution and induced velocity iteration of PBCF hydrodynamic performance prediction are written,and the hydrodynamic performances of open-water propeller and propeller/PBCF system are predicted.The results are compared with experiments,the scope of the errors are determined,the reliability of calculation method is verified.Compared with the results of open-water propeller and propeller/PBCF system,the energy saving effect and mechanism of PBCF are analyzed.Stress contours of three different kinds of open-water propeller and PBCF under different advance coefficients are calculated and analyzed,and the energy-saving mechanism and the reliability of calculation method are further verified.Then,the effect of diameter,pitch angle,installation angle,axial position and other perameters on energy saving effect of PBCF model test are researched.Parameter ranges are given respectively,and propeller/PBCF system hydrodynamic performance is predicted,then compared with the result of the open-water propeller,the change of energy saving effect is analyzed.Based on the results,the parameter optimization is proceeded,and the best parameters of test model are obtained.At last,the programs based on surface panel method of propeller/rudder system and propeller/PBCF/rudder system hydrodynamic performance prediction,and there are three different kinds of rudders which are ordinary rudder,skew rudder,variant skew rudder,then combined with the propeller and the PBCF test models,three kinds systems of the propeller/PBCF/ordinary rudder system,the propeller/PBCF/skew rudder system and the propeller/PBCF/variant skew rudder system are composed.And propeller/fins/rudder system hydrodynamic performance are predicted.Compared with the calculation results,the energy saving effect of PBCF is verified.