| With the development of ship industry and marine engineering equipment,the research of power propulsion devices are the key equipment to improve the hydrodynamic performance of ships.Compared with ordinary propellers,cycloid propellers have larger blade hydrodynamic area,less energy loss and superior maneuverability.The propeller instead of rudder change the thrust.It is suitable for low-speed ships and inland shallow water ships.The current research on cycloidal propeller is focused on the analysis of hydrodynamic performance,and few on the hull and cycloidal thrusters for self-propelled.In this paper,on the basis of studying the hydrodynamic performance of the cycloidal propeller and the prediction of hull resistance,further numerical simulation of the self-propelled test will be carried out to estimate the actual hull performance,judge the cooperation between the hull and the propeller.It is of great significance that the propeller can be really used in ships.The complex flow field changes caused by multi-degree-of-freedom motion of the cycloid propeller are the key points in studying the hydrodynamic performance of the cycloid propeller.In this paper,through the use of sliding grid and overlapping grid technology to simulate the movement law of the blade,taking NACA 3412 three-dimensional airfoil as an example,using different turbulence models to establish the numerical calculation scheme of the cycloidal thruster,selecting the best turbulence model.Based on the above numerical calculation scheme,the open water performance of the cycloid propeller was numerically simulated,and the rules of different feed rate coefficients and eccentric point positions on the open water performance were obtained.The research results show that the above numerical calculation method can effectively solve the numerical simulation problem of the cycloid propeller.Under the same feed rate coefficient,the cycloid thruster with larger eccentricity has higher open water efficiency.Based on the CFD technology,the hydrostatic resistance calculation of the 5415 ship model was carried out.By comparing the calculation results with the test values,the validity of the numerical calculation method based on STAR-CCM + software for the prediction of the ship’s hydrostatic resistance performance was verified.The actual research object of this paper is a tug that can be installed with cycloidal thrusters.Due to the lack of comparison of test data,the 5415 ship type example is used as a reference.The solution method based on VOF waves and multiphase flow is used to study the hull resistance.The change of the liquid surface can obtain the change of the resistance with the speed and the change of the flow field around the hull,which provides preparation for the numerical simulation of self-propelled navigation.Based on the self-propelled test method,the self-propelled numerical calculation of the cycloid propeller and ship was carried out.The cycloid propeller adopted a model with an eccentricity of 0.6 to obtain the various components of the propulsion efficiency at the selfpropelled point of the designed speed,visually indicate the interaction between the hull and the propeller through the flow field cloud map,predict the performance of the actual ship through the numerical results,and judge the cooperation between the propeller and the hull.In conclusion,the in-depth study of the cycloid propulsion has practical significance. |
