A parametric and numerical study on LNG-tank sloshing loads
As the demand of natural gas increases, larger LNG carriers are to be the most efficient commercial alternative for long distance transportation and a LNG-floating production, storage and offloading (FPSO) concept is introduced. A parametric/sensitivity study against non-matching scale parameters was carried out on the LNG-tank sloshing loads by using a computational fluid dynamics program. The effects of liquid turbulence and viscosity on impact pressures were negligible when air compressibility is not important. Liquid-gas density ratio is not a significant parameter on impact pressure when air compressibility is not important. Impact pressure was not sensitive to the change of ullage pressure in incompressible-gas models. To simulate the increase of impact pressure at low ullage pressure, a more sophisticated numerical model including gas compressibility, bubbles, and thermodynamic properties should be used. The comparison of one-fluid model (totally compressible) and two-fluid model (highly incompressible) implied that the measured pressures in model tests might be underestimated without the reduction of ullage pressure. This is an abstract of a paper presented at the 15th International Offshore and Polar Engineering Conference (Seoul, Korea 6/19-24/2005).