货舱内液化矿砂晃荡机理及数值计算研究

装载含水量较高矿砂的船舶在长时间摇摆和振动时,装载的矿砂会出现液化现象,其中的水分会析出,并在矿砂表面形成自由液面.受液化矿砂的粘性流动及表层液面的影响,运输该类货物的船舶易发生倾覆事故.建立了载有液化矿砂的三维货舱数值模型,探讨了货舱晃荡时矿砂液面、壁面载荷以及货舱横摇力矩的变化规律等;结合横摇实验现象对液化矿砂晃动机理和危害性进行了初步验证.结果表明：货舱内粘性矿砂的流动滞后于货舱的横摇运动,因而货舱横摇力矩的变化与货舱运动存在着相位滞后的关系,其最大值发生在货舱处于最大晃动角度后返回到平衡位置的过程中;货舱回摇过程中,倾侧的液化矿砂不能及时回流,会在一侧产生堆积,进而增加船舶倾侧力矩,最终可能会导致船舶倾覆.

Sloshing Mechanism Study and Numerical Calculation of Liquefied Ore in Cargo Hold

Ore cargo with high moisture content is characterized of liquefaction on the surface under the influence of sloshing or vibrations. Due to the viscosity of the liquefied ore and the free surface effect, this phenomena tends to capsize the ore carrier. This paper establishes the 3D numerical model of the hold, containing liquefied ore, and studies variations of the free surface, wall load and the roll torque. The ore sloshing mechanism and its harmfulness is studied through tests. The test results indicate that the movement of the viscous flow of ore lags the rolling movement of the cargo hold in terms of phase, and the maximum value of corresponding roll torque appears within the swaying back period of the ship, meaning the inclined fluid cannot flow back with the ship. This may cause lateral piling up of the liquefied ore and increase the heeling moment. The accumulation of the effect may result in tilting of ship and even capsize it.