﻿ 基于纵倾优化的油船节能研究
 舰船科学技术  2017, Vol. 39 Issue (8): 70-74 PDF

1. 华中科技大学 船舶与海洋工程学院，湖北 武汉 430074;
2. 船舶与海洋工程水动力湖北省重点实验室，湖北 武汉 430074;
3. 高新船舶与深海开发装备协同创新中心，上海 200240

A study on energy-saving for an oil tanker based on trim optimization
GAO Xian-jiao1, SUN Jiang-long1,2,3, HUANG Ben-shen1, ZHONG Cheng1
1. School of Naval Architecture and Ocean Engineering, Huazhong University of Science and Technology, Wuhan 430074, China;
2. Hubei Key Laboratory of Naval Architecture & Ocean Engineering Hydrodynamics, Huazhong University of Science and Technology, Wuhan 430074, China;
3. Collaboration Innovation Center for Advanced Ship and Deep-Sea Exploration, CISSE, Shanghai 200240, China
Abstract: The purpose of this study is to optimize the resistance performance of an oil tanker, in this paper, the three-dimensional ship model, calculation basin and structural meshing were performed by using the software of CATIA and ICEM according to the lines plan of the oil tanker, computational fluid dynamics software (FLUENT) was utilized to calculate the resistance of the oil tank in various trim conditions and drafts, then we compared the results calculated by numerical simulation with the towing tank test results to analyze the influence of trim variation on ship resistance performance. It is concluded that this method can find the optimal trim value in various drafts and provide practical advice for actual operating of the real ship, and as a result, it can improve the efficiency of energy-saving and emission reduction, and provide a new direction for the development of green ship.
Key words: structural mesh     numerical simulation     towing tank tests     trim optimization     energy-saving and emission reduction
0 引　言

1 数学模型 1.1 建立模型

 图 1 油船三维模型 Fig. 1 3D model of oil tanker
1.2 控制方程

RANS方程是粘性流体运动学和动力学的普适性控制方程[11]，本文用它作为求解船体阻力的基本方程，其形式如下：

 $\begin{split}& \rho {f_i} + \displaystyle\frac{\partial }{{\partial {x_j}}}\left[ {{\mu _o}(\frac{{\partial {u_i}}}{{\partial {x_j}}} + \frac{{\partial {u_j}}}{{\partial {x_i}}}) - \frac{2}{3}{\mu _o}\frac{{\partial {u_i}}}{{\partial {x_i}}}{\delta _{ij}}} \right] + \\& \displaystyle\frac{\partial }{{\partial {x_j}}}( - \rho \overline {{u_i}'{u_j}'} ) - \frac{{\partial p}}{{\partial {x_i}}} = \frac{{\partial (\rho {u_i})}}{{\partial t}} + \frac{{\partial (\rho {u_i}{u_j})}}{{\partial {x_i}}},\end{split}$ (1)

 $\frac{{\partial (\rho k)}}{{\partial t}} + \frac{{\partial (\rho k{u_i})}}{{\partial {x_i}}} = \frac{\partial }{{\partial {x_j}}}[{\alpha _k}{\mu _{eff}}\frac{{\partial k}}{{\partial {x_j}}}] + {G_k} + \rho \varepsilon ,$ (2)
 $\frac{{\partial (\rho \varepsilon )}}{{\partial t}} \!+\! \frac{{\partial (\rho \varepsilon {u_i})}}{{\partial {x_i}}} \!=\! \frac{\partial }{{\partial {x_j}}}[{\alpha _\varepsilon }{\mu _{eff}}\frac{{\partial \varepsilon }}{{\partial {x_j}}}] \!+\! \frac{{C_{1\varepsilon }^ * }}{k}{G_k} - {C_{2\varepsilon }}\rho \frac{{{\varepsilon ^2}}}{k},$ (3)

 $\frac{{\partial {a_q}}}{{\partial t}} + \frac{{\partial ({u_i}{a_q})}}{{\partial {x_i}}} = 0\;\;\;(q = 1,2),$ (4)

2 网格划分及计算策略

 图 2 计算模型 Fig. 2 Computational model

 图 3 计算域网格划分 Fig. 3 Grid partition of calculation basin

3 计算结果及分析 3.1 流场分析
 图 4 纵倾状态下船体动压力云图 Fig. 4 Contours of dynamic pressure corresponding to trim variation

 图 5 纵倾状态下船体表面波高图 Fig. 5 Wave height on ship surface corresponding to trim variation

3.2 CFD计算结果与试验结果的对比

 图 6 船模及其在拖曳水池中的运动 Fig. 6 Ship model and its motion in towing tank

 图 7 CFD值与试验值的对比 Fig. 7 Comparisons between CFD calculation and experimental data

4 结　语

1）经过试验验证，利用CFD数值模拟船体周围流场并求解船体水阻力完全可行。

2）在排水量保持不变的情况下，纵倾状态的变化对船体水阻力产生一定的影响，但具体的影响规律与船舶的装载状态有关，一般情况下首倾可降低阻力，但当船舶处于设计吃水状态时适当角度的尾倾也可以降低阻力。

3）实船运行过程中存在多个工况，本文只研究了3个工况下的纵倾对阻力的影响规律，对其他状态的具体规律还需要进一步研究，以便能够提供较为全面的数据指导实船航行。

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