Comparison of Sloshing Impacts for Rectangular and Chamfered LNG Tanks

One of the most utilised methods for the mitigation of impact forces due to the violent motions of LNG inside transported tanks is the chamfered geometry of the top corners. Nevertheless for some conditions the pressures may still reach a significant magnitude during the impacts of the fluid on the boundaries of the tank. Therefore there is the necessity to assess the magnitude of such pressure impacts, their numbers and also the location where those impacts are more likely to happen. In this study these issues will be addressed experimentally through comparison of data from two extensive measurement campaigns carried out with scaled models of different tank geometries across a number of different conditions. The number, position, magnitude and type of impacts in the most significant conditions for the two geometries are experimentally measured, assessed and compared. The comparison of the data shows that relevant impacts still occur in the case of a chamfered tank and that their magnitude, although reduced, is not negligible. In comparison with the rectangular tank there is one more location of high impacts because the fluid changes direction at the two corners of the tank. The most critical conditions are still for the medium/low filling levels, around 30%. For the higher filling levels, above 70%, the chamfered geometry is particularly effective, as it may be expected, in reducing the maximum pressures.