Numerical study on the dynamic RPT behavior of the damaged LPG carrier with combined CFD and VOF boiling model

Abstract

Reasonable evaluation of RTP (Rapid Phase Transition) characteristics in the damage leakage scenario is a significant consideration in the ship design and risk control of LPG (Liquefied Petroleum Gas) carriers. This paper proposes a numerical method to realize the natural leakage of LPG. CFD (Computational Fluid Dynamics) module is used to govern the mixed flow of multiphase fluids and solve motion response of the damage ship, while VOF (Volume of Fluid) boiling module is used to simulate RPT mechanism and deal with the multiphase interaction. Especially, UDF (User-Defined Function) is a key to perform the initial distribution of multiphase fluids and multiple physical field properties. To verify the accuracy of the numerical method on dealing with RPT, this paper performs the reliability analysis based on the experimental study of the liquid nitrogen injecting into water. By analyzing four leakage scenarios, main findings is divided into two aspects. Firstly, to truly assess the RPT behavior, the equivalent opening should consider the location and shape of the potential opening. Secondly, the cryogenic environment in the secondary barrier only occurs in a limited time and space. Overall, obtained results can provide valuable reference for the regulation revision and the ship design.