基于离散元法的极地船舶斜航冰载荷特性研究

Study on Ice Load Characteristics of a Polar Ship under Oblique Sailing Based on Discrete Element Method

  • 摘要: 【目的】随着气候变暖,极地航行船舶数量与航行窗口期呈现增长趋势。碎冰区斜航是极地船舶的典型作业场景,但针对该工况下的船舶冰载荷特性目前并无系统研究。【方法】以某极地船型为研究对象,应用离散元法对碎冰区船舶斜航状态下冰载荷进行预报。首先,针对目标船型建立数值模型,通过对比试验数据验证其准确性;其次,设定不同斜航角度、航速及冰厚,计算斜航过程中船舶受到的冰载荷;最后,深入分析不同漂角和不同冰厚条件下船舶冰载荷的分布特性和变化趋势。【结果】研究表明,随漂角增大,船舶所受碎冰阻力及碎冰侧向力呈非线性增长。在航速0.6m/s、海冰密集度60%,冰厚0.01497m的条件下,船舶在斜航工况15°漂角下相比直航工况,碎冰阻力与碎冰侧向力增幅分别达4.25倍、6.04倍。船舶在大于10°漂角工况斜航作业时,提高航速或进入大冰厚区域需注意碎冰阻力及迎冰侧碎冰侧向力突变可能造成的不利影响。【结论】研究结果为船舶在极地碎冰区斜航工况的安全性评估提供了支撑,为斜航工况下极地船舶冰载荷特性研究提供了参考。

     

    Abstract: Objectives With climate warming, both the number of polar navigating vessels and the duration of navigable periods are increasing. Oblique navigation in brash ice regions, a typical operating condition for polar vessels, heightens the uncertainty of ice loads on these ships, thereby increasing navigational risks. Methods Using a specific polar ship type as the research subject, this study applies the Discrete Element Method to accurately predict ice loads on ships operating in brash ice regions. First, a numerical model of the target ship type is established, and its accuracy is validated by comparing with experimental data. Next, ice loads experienced by the ship during oblique navigation are calculated by setting various oblique sailing angles, speeds, and ice thicknesses. Finally, an in-depth analysis is conducted on the distribution characteristics and variation trends of ice loads under different drift angle conditions. Results The study shows that with an increase in drift angle, both brash ice resistance and lateral force on the ship exhibit nonlinear growth. Under conditions of a speed of 0.6 m/s, 60% ice concentration, and an ice thickness of 0.01497 m, the brash ice resistance and lateral force at a drift angle of 15° in oblique navigation increase by 4.25 and 6.04 times, respectively, compared to straight navigation. During oblique navigation with drift angles exceeding 10°, caution should be exercised when increasing speed or entering regions with thicker ice, as sudden surges in brash ice resistance and lateral force on the ice-facing side may lead to adverse effects. Conclusions The research findings provide reliable data support for safety assessments of ships operating under oblique navigation conditions in polar brash ice regions, offering a valuable reference for predicting and studying ice loads on polar vessels in such conditions.

     

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