不同LNG液舱对晃荡敏感性的数值模拟

Numerical simulation on the sensitivity of LNG liquid tank to sloshing

晃荡对LNG船的液舱围护结构具有局部冲击力,不同结构的舱型对晃荡的敏感性不同。利用VOF(Volume of Fluid)流体力学模型对3种主要的LNG船液舱进行了数值模拟,根据不同充满度下液舱受力情况,对3种液舱的优劣以及最佳充满度要求进行分析,结果表明:在晃荡条件下,Membrane型(薄膜型)液舱对充满度的敏感性最大,最佳充满度液面范围为小于10%或大于80%;SPB型(Self-supporting Prismatic Type B)液舱的壁挡板有效地消耗了液体晃荡的能量,具有良好的防晃荡特性;Moss型(球型)液舱晃荡敏感性介于Membrane型与SPB型之间,充满度为50%~70%时受力最大。研究成果对于选择合适的LNG液舱结构形式具有一定的指导意义。

The sensitivity of LNG liquid tanks with different structures to sloshing is different because the sloshing has local impact on the protective structures of liquid tanks on LNG ships. In this paper, the Volume of Fluid（VOF） hydrodynamic model was used to simulate three main LNG liquid tanks. The advantages and disadvantages of three types of liquid tanks and their requirements on optimal fullness were analyzed based on the forces on tanks under different fullness. It is indicated that in the condition of sloshing, Membrane type liquid tank is the most sensitive to the fullness and the liquid level corresponding to its optimal fullness is less than 10% or more than 80%. Self-supporting Prismatic Type B type（SPB） liquid tank is the best in anti-sloshing performance for its baffle plank consumes the energy of liquid sloshing effectively. The sensitivity of Moss type liquid tank is between them and the force on it is the maximum when the fullness is in the range of 50%-70%. The research results can be used as the guide for choosing appropriate structure types of LNG liquid tanks.