High Performance Analysis Of Liquid Sloshing Problems In Containers With Complex Baffles

Liquid sloshing is a motion of fluid in a limited space,which has a high degree of randomness and nonlinearity.The sloshing problem exists widely in aerospace,nuclear power plants,marine engineering,land and sea transportation engineering and other fields.The liquid in the container will be shaken violently,when the vibration frequency of the liquid tank is close to the natural frequency of liquid sloshing in the tank or when the amplitude of the external excitation is large,which has a serious damage to the structure in severe cases.At present,one of the most efficient ways to reduce or suppress sloshing hazard is installing baffles in the liquid tank.Therefore,the parameter study of the baffle in the container is a very meaningful research for the analysis of the inherent properties and sloshing reduction effect of the system.The scaled boundary finite element method(SBFEM)is a new type of numerical simulation method developed in recent years.Compared with the boundary element method(BEM)and the finite element method(FEM),there is no singular integral problem in this method,and the boundary conditions can be satisfied automatically for infinite domain.At the same time,in the SBFEM,only the boundary of the calculation domain needs to be discretized,reducing the spatial dimension of the solution domain by one,which greatly saves the calculation costs.The SBFEM has been successfully applied in many research fields and has wide application value.Based on the SBFEM,the liquid sloshing problem in the container with complex baffles are studied in this paper.The main research content includes:(1)According to the potential flow theory,the SBFEM governing equations for the liquid sloshing problems in the 2D containers and 3D containers are derived from Laplace's equation.Through the numerical simulation results,it is found that this method has very high accuracy and calculation efficiency to deal with this kind of problems.(2)On the basis of contents(1),the free sloshing problem of liquid in 2D and 3D liquid containers are solved by using the SBFEM.The effects of different angles baffles with increasing of depth inside the container on the free sloshing frequency are investigated in six working conditions which are the 2D rectangular container,2D U-shaped container and cube container that have symmetrical baffles,the cylindrical container with inclined lower part,circle ring container and PCS gravity water container of nuclear power plant that have annular baffles.At the same time,the free sloshing frequencies of the liquid in the 2D rectangular container,cube container and cylindrical container with inclined lower part with the combined baffle,double baffle and the length of baffle are calculated.Finally,the free sloshing frequency of the 2D double U-shaped container is also studied.(3)On the basis of contents(2),the SBFEM dynamic equation of liquid sloshing force in the containers under external lateral excitation are further calculated,and the additional mass of liquid sloshing is solved.For the 2D rectangular container,2D U-shaped container,cube container,cylindrical container with inclined lower part and circle ring container,the influence of different angles baffles with increasing of depth inside the container on the sloshing force and addition mass are studied,the best reduction effect of baffles for liquid sloshing is obtained.At the same time,the sloshing force of the 2D rectangular container,cube container and cylindrical container with inclined lower part with combined baffle,double baffle and the length of baffle are calculated.Finally,the Passive Containment Cooling System—PCS gravity water container of nuclear power plant with annular baffles under the earthquake wave is also studied.