Research Of Moving Particle Semi-implicit Method On Fuel-coolant Interaction In Core Melt For Fast Breeder Reactor

The moving particle semi-implicit method(MPS),which is a fully Lagrangian particle method based on particle and their interactions,has the advantage of simulating complex hydrodynamic phenomenon such as incompressible interface flow,fluid-solid mixture flow and multiphase flow and is widely applied to engineering and theoretic study.In this paper,it is attempted to apply MPS method to the study of severe core disruptive accidents by MPS modeling and Fortran coding.Firstly,the theoretic study of MPS method was introduced in this paper,including key models and various boundary conditions.In addition,the strategy of choosing key parameter was given during the calculation,such as the initial distance between two particles,the cutoff radius of a particle and the time step.The optimizing method and calculation procedure were introduced through the analysis of the algorithm.Secondly,through the collapse of a water column and one-dimensional heat penetration into a semi-infinite medium,the numerical simulation of flow and heat transfer were verified by the comparison with the experimental and exact analytical solutions of these two numerical tests.Meanwhile,single phase flow was simulated with different density on basis of the collapse of a water column.The results showed that the density of the liquid had little effect on the flow.On the other hand,the pressure of the wall with the pressure oscillation relief model was compared with that of the original one.The model was verified to be effective to improve the stability of the calculation.Lastly,the analysis of the interface temperature of FCI process was conducted and compared with the results of explicit enthalpy model and the analytical calculation.It was concluded that the interface temperature calculated by the MPS model increased slower than that calculated by the explicit enthalpy model,but the results was closer to the analytical results.The simulation of jet injection was simulated under different conditions with the density ratio from 0.5 to 2 and the initial velocity 1m/s.The process and phenomenon of jet injection was clearly observed in the simulation,and it showed that the liquid impacted by jet was more and higher with higher density ratio and initial velocity.It showed that simulation of the two-phase flow,whose interface was in contact originally,was better than that of whoseinterface was not in contact in the simulation of with high density ratio,through the simulation of uranium and sodium two-phase flow with the density ratio close to 20.