The Numerical Study On Sloshing Liquid In Fast Reactor Vessel Considering Fluid-Structure Interaction

The fast reactor body is a large pool structure containing a large amount of liquid sodium.In the case of an earthquake,the container will vibrate,causing the liquid inside it to slosh.The shaking of the liquid sodium will affect the vibration of the container and the internal components of the pile,resulting in a fluid-solid coupling effect.This fluid-solid coupling effect may be on the wall of the vessel and Various components in the main container,such as a heat shield,cause structural damage,and at the same time,a large overturning moment may be generated to damage the support of the main container.When the swaying wave height is large,it is highly likely to hit the cone top cover on the upper part of the main container,causing impact damage to the cone top cover.In order to ensure the structural integrity of the stack body and various equipment components under earthquake conditions,and to ensure the safety of the reactor,it is necessary to consider the fluid sloshins of the fast reactor reactor body.At present,the numerical research on liquid sloshing at home and abroad is mainly for geometrically simple square or cylindrical waters,and there is less research on liquid sloshing in complex structures with internal components such as fast reactor body,so it is necessary to This complex structure of the body performis research on liquid sloshing.Secondly,in many previous studies on the numerical simulation of liquid sloshing,the damping effect and the mutual coupling between fluid and structure have not fully considered the liquid,so it is necessary to consider the damping effect of the liquid and the interaction between the fluid and the structure.In addition,the numerical simulation method or model of the liquid sloshing of the fast reactor reactor has been carried out without experimental verification.so it is necessary to carry out experimental verification on the numerical simulation method or model.In this paper,the large-scale commercial sof-tware ANSYS is used to study the liquid sloshing problem in the fast reactor stack shrinkaoe model,and two structural models of pure loop domain and fast reactor stack complex structure are established.The liquid is simulated by Fluid30 unit and Fluid80 unit,and the structure uses Shel163 unit.Simulation,fluid-solid coupling is achieved by coupling coincident nodes.Through the modal analysis,the natural vibration characteristics of the structure and the sloshing characteristics of the liquid are studied.Through the kinetic time history analysis and spectrum analysis,the parameters such as the sloshing wave height,liquid pressure,structural stress intensity and the overall resultant force and resultant moment of the liquid are obtained.At the same time,it is compared with the results of the seismic station test to verify the feasibility of the calculation method and the accuracy of the calculation results.1.Through the research in this paper,it is proved that this finite element method is reasonable and feasible tor studying the liquid sloshing problem in the complex structure of last reactor bulk.2.Through the study of the liquid sloshing characteristics in the complex structure of the pure ring domain and the fast reactor stack,it is found that the existence of the internal components of the reactor will first reduce the modal frequency of the liquid,and the first-order modal frequency will be reduced by 16.93%,followed by the liquid sloshing.Inhibition,the maximum wave height of the liquid is reduced by 28.87%.and the maximum hydrodynamic pressure is reduced by 20.31%.Therefore,in the conservative case,the wave height and pressure of the pure ring domain can be used to replace the sloshing wave height and hydraulic pressure value of the liquid in the complex stack.3.Fluid80 unit can simulate the sloshing characteristics of liquid,and can extract the sloshing frequency,sloshing wave height and hydraulic pressure of liquid.Under the sinusoidal three-wave excitation,when the damping ratio of the liquid is 0.12,the error between the finite element calculated value and the experimental measured value of the sloshing wave height is within 10%.and the error between the finite element calculated value and the experimental measured value of the hydraulic pressure is 15%.Within.The Fluid30 unit can be used to study the fluid-solid coupling problem of non-sloshing liquids.4.When the liquid is simulated by Fluid80.Fluid30 and additional mass,it is found that the stress intensity of the structure is not much different when the fluid-solid coupling is considered and the fluid-solid coupling is not considered,and the first-order sloshing frequency of the liquid is much lower than the structure.The first-order vibration frequency indicates that the fluid-solid coupling effect has little effect on the model.