The Research On Performance Of Composite Propeller's Cavitation And Hydrodynamics Of Cavitation

At present,the development of ships tends to be larger and higher speed.Once cavitation occurs,it will inevitably affect the hydrodynamic performance of propeller.Lead to cavitation erosion,destroy blade surface material;At the same time,it causes the vibration of hull tail and cavitation noise.In recent years,cavitation has been the focus of international hydrodynamic research.In order to control cavitation generation,conventional metal propellers usually change the geometric size and shape of propellers,such as selecting airfoil with small thickness and drilling at blade root,etc.However,due to the large size and weight of propellers and complicated structure,the effect is often not ideal.The emergence of composite propeller provides a new opportunity for the control of cavitation.The structural characteristics and working principle of composite propeller are quite different from that of traditional metal propeller,so the cavitation mechanism and its influence are quite different.Based on this,this article in view of the general DTMB4381 propeller blade type,using the CFD method combined with finite element analysis method,on the cavitation performance of the composite propeller hydrodynamic performance and cavitation are studied,and compared with calculation results of metal screw analysis,explores the composite propeller cavitation mechanism,the concrete research content is as follows:The numerical simulation method of propeller open water is established based on RANS equation.The mesh division of the whole computational domain is realized by the hybrid mesh method which combines tetrahedral mesh and structured mesh.The correctness of this method is verified by grid independence analysis.The effects of different turbulence models on the hydrodynamic performance of metal propellers were studied.Compared with the experimental data in literature,an effective turbulence model suitable for this study was proposed.The pressure distribution and flow field of propeller blade surface under different working conditions are analyzed.Poly real-Hexcore rotating domain based on Mosaic technique combining the flow field of structured mesh and the overlap grid,combined with computational fluid dynamics method,a numerical simulation of steady cavitating propeller method is established,the metal propeller are studied under different conditions,different cavitation number of unsteady cavitating flow,discusses the different turbulence models,different cavitation model and discrete format on the result of calculation,analysis of the metal under different working condition and the cavitation number of propeller cavitation area,the degree of cavitation and cavitation hydrodynamic performance.The accuracy of cavitation numerical simulation method is verified by comparison with the results in the literature.A numerical simulation method of composite material propeller cavitation was established by using CFD,FEM and geometric reconstruction program based on MATLAB.The fluid-structure coupling calculation of 4381 composite material propeller under different working conditions was completed,and the deformation of composite material propeller was analyzed.The 3d geometric reconstruction of composite material propeller after deformation was completed by combining MATLAB and 3d configuration software UG.The steady cavitation performance and hydrodynamic performance of the composite propeller under different working conditions and different cavitation Numbers were studied.