| Theoretical calculation of propeller-hull interaction is a fairly complex subject, whichinvolves the induced velocity field of hull and rotating propeller in ideal fluid, viscous flowvelocity field within the boundary layer, the mutual influence of viscous flow field and inviscid flow field and so on. More difficult, however, is related to the boundary layerseparation and the influence of free surface. The problem of viscous flow field andhydrodynamic performance of propeller and its interaction with the hull of the ship have beenconcerned by ship research and designer. Installing the energy saving appendages in ships isan effective method for the energy saving, which have characteristics of significant energysaving effect, simple structure and low cost. The energy saving device was studied by anumerical method and the influence of the energy saving device on ship wake was analyzedfrom the point of flow field details, which had an important theory meaning and engineeringvalue.With the development of CFD technology, now the study of physical objects have beenmore and more complex. The working conditions are increasingly close to the actual situationif take the energy saving appendage, rudder, propeller into account to the study, for example,relate to the influence of heave, trim, wave on the calculation results.Although some of the key technology of the water surface ship flow field numericalprediction technology has made good progress, research work mainly focused on thedestroyers or the hull form of medium block coefficient. Whether at home or abroad, theresearch on the flow field and hydrodynamic CFD of large block coefficient of full hull formhaven’t been systematic studied and analyzed. In fact, oil tanker and bulk carrier of the threemajor types of civilian ship are large full ship, therefore the research on large full ships’numerical simulation method has a strong market demand and has a particular far-reachingsignificance. Based on CFD technology, this paper studies a certain75000DWT bulk carrierwith this large full ship hull and the steady interference problems between energy savingappendage and propeller.The paper verifies the feasibility of ANSYS ICEM CFD and STAR CCM+this twosoftware applications that apply them in the numerical prediction of overall hydrodynamicperformance of naked hull and paddle. By predicting the overall hydrodynamic performance of naked hull and paddle of KCS, then the calculated values can be obtained. Compared withthe experimental values, the results show that this method is perfectly suitable for theprediction of ship hydrodynamic performance and the analysis of flow around the ship.Meanwhile, some experiences in models creation, meshing, boundary conditions setting wereaccumulated, which had laid a good foundation for the further use of CFD technology tostudy the hydrodynamic performance and flow fields around the ship.Based on the accurate prediction of KCS ship hydrodynamic performance, in order tovalidate the applicability of mesh generation method and turbulent model, then it calculatesthe free surface of the hydrodynamic performance of the naked hull and boat-paddle-arudder system of a75000DWT bulk carriers. After that, we add two kinds of energy savingappendage on the rudder and conduct free surface of steady hydrodynamic performancecalculations of the ship-propeller-rudder-rudder ball propulsion system and theship-propeller-rudder-rudder ball type thrust fin system.The paper analyzes the result of thecalculation and discusses the influence of the mutual interference of hull, propeller and energysaving appendage on the each of the three, so we can obtain the efficiency of energy savingand drag reduction of rudder ball and rudder ball type thrust fin, and then analyzes theworking mechanisms of energy saving appendage from the flow field. |
PDF Full Text Request