| PBCF is a type of energy saving device, which get energy back by reducing hub vortex ofpropeller. In1980s, PBCF appeared as the first time, and it is used widely on ships nowadayswith getting a satisfactory result of energy saving. However, the design method of PBCF isstill relied on experience in practical application without a theoretical but reliable andapplicable design method.The thesis firstly based on the existing mechanism analysis has worked out themechanism analysis on quantitative foundation to get a concept of the action of eachcomponent quantitatively. The conclusion then was checked with more than100examples’CFD calculations. And then, a theoretical design method has been proposed based onviscosity CFD flow field analysis to achieve the purpose of reducing tangential velocity ofwake flow as much as possible. Based on the method, the influences of parameters havebeen analyzed and some suggestions are made. The feasibility of using simplified PBCFgeometry form was investigated. The energy saving effect and the improvement of wakeflow from designed PBCF is predicted by CFD analysis..The open water test of the propulsor set was carried out in the towing tank for validatingthe accuracy of CFD prediction of hydrodynamic forces. A propulsor with three alternatives ofPBCF was tested in the large cavitation tunnel with uniform inflow to validating the energysaving effect experimentally, and to conduct LDV measurements for further investigating theeffect in the wake field. It shows that the numerical prediction of hydrodynamic forces andthe velocity distribution in the wake are in good agreements with the results of tests, and thedesign goal is achieved very well as expected.. |
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