Development of two-dimensional lattice Boltzmann code DG2LBM for computational fluid dynamic problems in nuclear reactor safety component design

A 2-dimensional computational fluid dynamic analysis program DG2LBM by using Lattice Boltzmann Equation (LBE) with momentum exchange boundary conditions is developed and it is applied to a feasibility study of nuclear reactor safety component such as a reactor building floor weir (RBFW), a simple as well as an effective option to sediment particulate materials generated after loss of coolant accident of a nuclear power plant and. The program is benchmarked against a standard problem of a flow past a cylinder at relatively low Reynolds numbers, the RBFW is simulated for diverse parametric conditions such as height, inclination angle, number of weirs (1 or 2) and the distance between two weirs. The weir performance is measured by the area of quiescent and/or downward reverse flow region where particles have more chance to sediment. It is found a wake causing reverse downward flow behind the weir mainly contributes to generating the quiescent flow region. And the most effective option in terms of particle sedimentation performance is found to be relatively tall double weirs separated by 2 weir heights. (orig.)