A study on the prediction of rollover phenomena from the stratified LNG storage tank
摘要
When liquefied natural gas (LNG) of different density and temperature is added to a partially filled LNG tank, temporarily stratified layers are present together while as time elapses the layers reach to an equilibrium state of the same density and temperature with each other. The subsequent abrupt mixing of the layers leads to a great deal of vaporization on the free surface of the top layer. With a suggested double-diffusive convection model to predict this kind of rollover phenomena, the conservation actual rollover accident in the La Spezia LNG receiving terminal, Italy in 1971, is selected as a model case. Our calculation considers more accurate variations of the density due to the change of LNG temperature and composition during every computation step. Thus we approach the actual La Spezia rollover time more closely than any other simulation result. This calculation method applied here can predict the occurrence time of rollover more precisely and be used for the prevention of rollover in advance. (author). 15 refs., 8 figs., 1 tab.