大型油轮压载水舱泥沙淤积试验研究

Experimental studies on sedimentation in VLCC ballast tanks

大型油轮进入多沙水域,停泊港口置换压载舱水时,舱内泥沙沉积于压载水舱底部,很难清淤。将压载水舱分隔为边舱和底舱,以边舱作为泥沙沉淀舱,泥沙沉淀后较清水体流入底舱,是治理压载水舱泥沙淤积的一种新方法。以舟山地区多沙水域为背景,建立了大型油轮压载水舱边舱正态水沙模型,提出了压载水舱不同结构形式下的压舱水流动方法,通过多组次试验,分析了油轮压载水舱泥沙的淤积过程和沉积规律,优选了压载水舱泥沙落淤最佳结构方案。研究结果表明:通过油轮压载水舱边舱沉淀泥沙的方法,能使压载水中约80%的泥沙落淤,仅20%左右泥沙进入底舱。该模型试验为国内首次大比尺船舶压载水舱泥沙淤积试验,可为大型油轮、船舶压载水舱泥沙治理提供新的途径。

It is difficult to dredge silted sediment on the bottom of ballast tanks after VLCC（ very large crude carrier） enters and anchors in harbors for replacement of ballast water in turbid waters. A new way of governing silt in the VLCC replacement of water ballast tanks is to separate the ballast tanks into the side ballast tanks and the bottom ballast tanks,and the side ballast tanks are taken as the main sediment deposition cabins instead of the bottom of the ballast tanks,so that the water inflowing the bottom ballast tanks will contain less slit. In this paper,a normality model is established for water sediment in VLCC side ballast tanks based on studies of high sediment concentration in the Zhoushan coastal waters,Zhejiang Province,China. The regular pattern of ballast water flowing into the different ballast tanks is also constructed. Tests on four schemes are made and the best structure design of the ballast tank sediment silt preferably among the four test designs is selected. The ballast tanks sediment deposition processes and laws are obtained from experiments. The analysis results of experiments show that 80% of sediment deposition occurs in the side ballast tank,and only about 20% of sediment enters the bottom ballast tanks.This is the first large scale model study of VLCC ballast tank sedimentation in China,and the model studies have provided a new way in controlling sedimentation in VLCC ballast tanks. The experimental results can be widely applied to deal with sediment depositions in the other large ship ballast tanks.