Effect of heat transfer coefficients on evaluation of temperature distribution in membrane type LNG carriers

The major challenge of designing the hull of an LNG carrier is to reliably predict the hull temperature distributions. The study objective is to introduce a new process for obtaining improved temperature distributions in the multi-layered barriers of a membrane type LNG carrier. An in-house code capable of estimating the heat transfer coefficients, boil off ratio, and the temperature distributions in the LNG carrier compartments was developed based on the fundamental heat transfer theory. The in-house code was verified by comparing hull temperatures obtained from calculations by other researchers. The finite element analyses (FEAs) with newly calculated heat transfer coefficients derived from the in-house code quite much improved the accuracy of the temperature distributions in the membrane-type LNG cargo holds than those with the nominal ones. It was concluded that the in-house code is necessary to obtain more reliable temperature distributions using the FEAs.