铺管船月池结构减阻优化设计

Optimization Design of the Moonpool Structure of Pipe-Laying Vessel for Drag Reduction

为了减少铺管船的航行阻力,对月池结构进行优化设计。月池模型CFD计算结果与自然周期、水搅动模式的理论计算值的对比表明,该铺管船月池水体运动同时存在活塞模式和晃荡模式。为了降低月池附加阻力,提出3种月池优化方案:切口角方案,楔形角方案和凸缘结构方案。基于CFD仿真结果,量化各方案降低附加阻力的性能及其组合减阻效果。研究表明:切口角β=63.43°、楔形角α=5.71°时阻力性能最佳;而在切口角β=45°、楔形角α=5.71°的月池中安装1 m宽的凸缘结构对降低阻力没有任何作用,相反,由于凸缘结构与楔形结构之间的相互作用,阻力反而会增加,表明不同方案的组合效果不是简单的叠加,而是存在复杂的相互作用。因此,在使用多种减阻技术的组合方案时应进行全面的参数敏感性分析,从而确定最佳参数组合。

In order to reduce the resistance of pipe-laying vessel,the moonpool structure is optimized.Comparing the CFD results of the moonpool model with the theoretical values of the natural period and the water agitation mode indicated that the motion of the water in the moonpool of pipe-laying vessel has both piston modes and sloshing modes.In order to reduce the additional resistance of the moonpool,three optimization schemes were proposed:the cut-off angle scheme,the wedge angle scheme and the flange scheme.Based on the simulation results of CFD,the performance of each scheme to reduce added resistance and their combined drag reduction effect are quantified.It indicated that the resistance performance is the best when cut-off angle β=63.43° and the wedge angle α=5.71°,while the installation of a 1 m wide flange in the moonpool has no effect on reducing resistance when β=45°andα=5.71°,instead,the resistance increases due to the interaction between the cut-off angle and the wedge structure,indicating the combined effect of different resistance reduction schemes is not simply superimposed,but also involves complex interaction between them,hence,a comprehensive parameter sensitivity analysis should be performed to determine the optimal parameter combination when a combination of multiple resistance reduction technologies were used.