| In recent decades,with the rapid development of waterjet propulsion technology,waterjet propulsion is widely used in medium and high-speed ships because of its unique advantages.The most widely used waterjet propeller is the tail plate waterjet propulsion with flush type intake duct.Grilles are arranged at the inlet of the intake duct of the waterjet propulsion to prevent sundries from being sucked into the intake duct,which threatens the safety of ship navigation.Although the structure of the grille component is relatively simple,the current relevant research shows that its design has an important impact on the speed of the waterjet propulsion ship.At present,a series of domestic work has been carried out on the performance research of the grille arranged inside the waterjet propulsion under the action of fluid,such as hydrodynamic and vibration,but the research on the related problems of the grille is less and not deep enough.In this paper,the numerical calculation method of fluid structure interaction is proposed to systematically calculate the stress and strength characteristics on the surface of the grille,and then analyze the variation law of the flow field,surface stress and strength characteristics around the grille.Thus,it provides some guidance for the design and optimization of grille components in waterjet propulsion.Firstly,combined with the computational fluid dynamics numerical calculation method based on the Detached eddy simulation(DES),two sets of numerical calculation models of inlet channel + grille and water jet propulsion pump + inlet channel + grille are established.The two sets of numerical calculation models are numerically calculated under the conditions of different speed,different inlet speed ratio and different propulsion pump speed,and the forces on the grille surface are analyzed According to the distribution characteristics of the flow field around the grille,it is found that the distribution of the flow field around the grille is not uniform,and the stress on the grille surface shows a certain regularity.Then,on the basis of the above computational fluid dynamics calculation results,combined with the finite element(FEM)method and fluid structure coupling theory,taking starccm + and ABAQUS as tools,the one-way fluid structure coupling and two-way fluid structure coupling collaborative simulation calculation and analysis methods of grille structure strength in different calculation models are established to calculate the strength characteristics of the grille arranged at the inlet of the inlet channel,The strength characteristics of grille under different calculation models and conditions are summarized.The calculation results show that under high-speed conditions,the grille currently used is accompanied by the risk of structural failure.Finally,according to the known grille section design method,on the premise of ensuring the grille thickness,length,installation angle and other parameters,the current grille section form is improved to form two new symmetrical section forms of grille,and then the surrounding flow field,structural static strength The results show that the symmetrical section grille is helpful to reduce the local stress of the grille. |
