Prediction Of Unsteady Performances Of Ducted Propeller

Ducted propeller has been widely used on various ships such as towboat and fish boots, for it can absorb fully the engine power in variable operating conditions and has higher efficiency in heavy loading conditions compared with conventional propellers. Furthermore, with development of CFD methods and improvement of commercial software many complicated engineering problems can be solved accurately. So CFD software is used more widely in the field of ship fluid mechanics.In present paper the flows around conventional propeller, ducted propeller, pod propeller and ducted propeller with pre-swirl stators are simulated by FLUENT software and the mesh are generated by GAMBIT software. The space domains are discretized into unstructured tetrahedron mesh. The spatial discretizations are the first order upwind difference scheme. The SIMPLEC method based on velocity-pressure coupled solver is used. The present research works are as follows,1. The open water hydrodynamic performances of DTMB P4119 propeller are predicted and validated by MRF method. Furthermore, the dependence of the mesh and the adaptability of turbulent model are studied. 2. In order to analyze the influence of different pitch ratios, expanded area ratios of propeller and duct profiles, the hydrodynamics performances of three ducted propellers (Ka4-5512+JD7704 ,Ka4-7008+JD7704,Ka4-5512+No.19a) are simulated respectively by MRF method. It shows the numerical results are accurate and the numerical method is correct.3. The steady performance of Ka4-5512+No.19a ducted propeller is predicted by sliding mesh method. Compared with experimental results, it shows good agreement and the present method can be applied in engineering practice.4. The mixing plane method is used to predict the open water hydrodynamic performance of pod propeller. Compared with experimental data, the numerical results show good agreement.5. Finally, the sliding mesh method is applied to simulate the flow around pump jet propulsor with pre-swirl stators. The hydrodynamic performance of the propulsion is predicted. The interactions between stators and propeller are analyzed.