空气压缩效应对船舶破损进水特性的影响

he effect of air compression on the flooding of damaged ship

破损的密闭舱室内残余空气的流通性和压缩性对破口进水或横贯进水速度有重要的影响。本文基于伯努利原理和波义尔定律,采用准静态法建立了考虑空气压缩效应的船舶破损进水数值计算方法。首先对简易舱室破损进水进行时域模拟,通过与现有数据的比较验证数值计算方法的有效性;然后以ITTC标准驳船模型为对象,开展考虑空气压缩效应和非水密门影响的破损舱室进水数值计算,分析空气压缩效应与非水密门对舱室压力、进水速度、水面高度等因素的影响。数值计算结果表明,当舱室存在空气压缩效应时,舱室达到进水平衡时间减少,水面高度减小,对船舶稳性不利;当考虑舱室之间非水密门影响时,舱室达到进水平衡过程会产生变化,非水密门受力临界较大情况下会阻碍水漫延进入下一舱室,缩短舱室达到进水平衡的时间和水面高度。本文采用的数值计算方法能在较短时间内较好地模拟考虑空气压缩效应的船舶破损进水过程,为破损船舶浮性稳性精确预报和应急处置决策奠定基础。

The fluidity and compressibility of the residual air in the damaged closed cabin have an important effect on the flooding fluid through the damaged cabin.Based on Bernoulli's principle and Boyle's law,a quasi-static method numerical calculation method for flooding fluid considering the effect of air compression is established.Firstly,the time domain simulation of flooding fluid in the simple cabin is carried out,and the validity of the numerical calculation method is verified by comparing with the existing data.Then,taking ITTC standard barge model as the object,the numerical calculation of flooding fluid in damaged cabin is carried out considering the effect of air compression and non-watertight door,and the influence of air compression effect and non-watertight door on cabin pressure,flooding speed,water height and other factors is analyzed.The numerical results show that when the air compression effect exists in the cabin,the time to reach the water flow balance decreases and the water height decreases,which is unfavorable to the stability of the ship.When the influence of non-watertight doors between cabins is considered,the process of reaching water balance in the cabin will change.If the non-watertight doors have a large critical force,it will prevent water from spreading into the next cabin,greatly shortening the time for the cabin to reach water balance and the water height.The numerical calculation method used in this paper can simulate the flooding of damaged ships considering the effect of air compression in a short time,and lay a foundation for the accurate prediction of the floating stability of damaged ships,and provide help for the rescue of ships after distress.