Simulations of TOSQAN containment spray tests with combined Eulerian CFD and droplet-tracking modelling

Abstract

The spray experiments TOSQAN 113 and TOSQAN 101, which were performed in the TOSQAN facility (located at the Institut de Radioprotection et de Sûreté Nucléaire, France), were simulated with the computational fluid dynamics (CFD) code CFX4.4 combined with a droplet-tracking model. The main purposes of the tests were to investigate, respectively, the influence of containment sprays on mixing of the stratified atmosphere and on atmosphere depressurization. Two- and three-dimensional models of the TOSQAN vessel for the CFX4.4 code were developed. The modelling approach is based on an Eulerian description of the continuous phase (gas), a Lagrangian description of the dispersed phase (spray droplets), and a two-way interaction between the phases. Droplets act as sources or sinks of energy, mass and momentum in the single-phase gaseous field. In addition, a simple droplet–wall interaction model was incorporated into the code, allowing the evaporation of the liquid film formed by deposited droplets. The results of the simulations are compared to experimental data. For test TOSQAN 113, the emphasis is on the comparison of non-homogeneous helium distribution, whereas for test TOSQAN 101, the emphasis is on the comparison of pressure and non-homogeneous temperature distribution. The comparisons of experimental and simulation results of both tests support the adequacy of the combined CFD and droplet-tracking approach.