Numerical analysis of jet injection behavior for fuel-coolant interaction using particle method

The numerical method used in this study is Moving Particle Semi-implicit (MPS) method which is based on moving particles and their interactions. Grids are not necessary, so that large deformation of fluids can be: calculated without grid tangling. Particles move in fully Lagrangian description. Thus, convection terms are not necessary to discretize and numerical diffusion does not arise. To understand the behavior of jet penetration, water jet injection into a pool of a denser fluid under non-boiling and isothermal conditions is analyzed using the MPS method. The density ratio of the denser fluid (Fluorinert) to water is 1.88. This is categorized to the coolant injection (CI) mode where the coolant is assumed to be injected into the melt pool. The calculation results are compared with experiments which were conducted by Park et al. in Japan Atomic Energy Research Institute (JAERI) for visualization of basic processes in fuel-coolant interaction (FCI). The jet penetration behavior of the three-dimensional calculation agrees with the experiment. It is found that the jet penetration process is divided to two stages and, at the first stage, the coolant jet penetrates deeper than existing correlations of the breakup length in the CI mode.