SENSITIVITY ANALYSIS ON THREE-DIMENSIONAL NUMERICAL SIMULATION OF LIQUIFIED NATURAL GAS SLOSHING IN TANK

摘要

A series of sensitivity analyses is carried out against flow models (i.e. inviscid, laminar and turbulent models), mesh size and scaling factor based on Froude scale laws on the time history of sloshing impact pressures and computational requirements. In order to capture the complex wave breaking and gas trapping phenomena associated with the violent liquid sloshing motion, a free surface tracking approach called Volume of Fluid (VOF) method is employed. The computational results show that the inviscid flow model based on Euler equation would provide a reasonably accurate impact load prediction and with efficient computing time. This is because the inertia force is the dominant factor in the sloshing movement compared to the localized viscous effect. For mesh sensitivity analysis, 5mm and 10mm mesh size models have been simulated for 20 cycles. It is found that 5mm resolution provides better results than 10mm. Further mesh refinement is expected to provide better results, but with significant computational power requirement. Finally, the full-scale simulation results have also been compared against the model scale results. The simulated impact pressures derived from model scale based on the Froude scale law agree with those of calculated from the full scale simulation.