﻿ 基于STAR-CCM+的30 000 t散货船水阻力计算
 舰船科学技术  2023, Vol. 45 Issue (22): 34-39    DOI: 10.3404/j.issn.1672-7649.2023.22.006 PDF

1. 大连海事大学 轮机工程学院，辽宁 大连 116026;
2. 浙江清华长三角研究院，浙江嘉兴 314006;
3. 清华大学 能源与动力工程系，北京 100084

Calculation and analysis of water resistance of 30 000 t bulk carrier based on STAR-CCM+
ZHAI Jin-guo1, XIN Rong-bin1, WANG Zong-yu2,3, ZHANG Ji-feng1,2, ZHANG Hai3, JI Yu-long1
1. College of Marine Engineering, Dalian Maritime University, Dalian 116026, China;
2. Yangtze Delta Region Institute of Tsinghua University Zhejiang, Jiaxing 314006, China;
3. Department of Energy and Power Engineering, Tsinghua University, Beijing 100084, China
Abstract: Considering that different calculation strategies in the process of ship numerical simulation have different effects on the accuracy of ship resistance, this paper compares and analyzes several influential factors in the process of STAR−CCM+ software simulation, and discusses the changes in ship resistance of 30000 t bulk carrier in different calculation areas, grid density, turbulence models and other conditions. The analysis results show that, compared with reducing the grid size, increasing the calculation area appropriately can reduce the calculation time while ensuring the calculation accuracy. The SST K-Omega turbulence model is recommended for simulation calculation. The simulation error of the calculation method proposed in this paper is within 5%, which can meet the needs of practical engineering design. It is a reliable numerical simulation method of ship resistance and can provide a reference for the calm water resistance numerical calculation of bulk carriers.
Key words: numerical simulation     ship resistance     computational domain     grid density     turbulence model
0 引　言

1 数值计算 1.1 数值计算模型

1.2 控制方程

 $\frac{{\partial \rho }}{{\partial t}} + \frac{{\partial (\rho {u_i})}}{{\partial {x_i}}} = 0，$ (1)

 $\frac{{\partial (\rho \overline {{u_i}} )}}{{\partial t}} + \frac{{\partial (\rho \overline {{u_i}} \overline {{u_j}} )}}{{\partial {x_j}}} = - \frac{{\partial \bar p}}{{\partial {x_i}}} + \frac{\partial }{{\partial {x_j}}}\left( {\mu \frac{{\partial \overline {{u_i}} }}{{\partial {x_j}}} - \rho \overline {{{\dot u}_i}{{\dot u}_i}} } \right) + \rho {f_i} 。$ (2)

1.3 边界条件的选取

 图 1 数值计算区域划分 Fig. 1 Division of numerical calculation area
1.4 网格划分

1.5 物理模型的选择

 ${\alpha _i} = \frac{{{V_i}}}{V} 。$ (3)

 图 2 船体水的体积分数 Fig. 2 Volume fraction of water on the hull
2 数值计算的影响因素分析 2.1 计算区域大小对计算结果的分析

2.2 网格密度对计算结果的影响

2.3 湍流模型对计算结果的影响

3 数值计算方法验证 3.1 数值计算结果可视化分析

 图 3 船舶航行波形图 Fig. 3 Ship motion waveform
3.2 不同航速下船舶阻力变化

 图 4 数值计算结果对比 Fig. 4 Comparison of numerical calculation results

 ${C_f} = \frac{{0.4631}}{{{{({\rm{lg}}{Re} )}^{2.6}}}} ，$ (4)

 ${C_f} = \frac{{0.455}}{{{{({\rm{lg}}{Re} )}^{2.58}}}}，$ (5)

 ${C_f} = \frac{{0.066}}{{{{({\rm{lg}}{Re} - 2.03)}^2}}}，$ (6)

ITTC1957公式：

 ${C_f} = \frac{{0.075}}{{{{({\rm{lg}}{Re} - 2)}^2}}} 。$ (7)

 图 5 摩擦阻力对比 Fig. 5 Friction resistance comparison

 图 6 阻力占比 Fig. 6 Resistance ratio
3.3 KCS船舶航速验证

KCS船舶实验数据来自文献[17]，由于文献中将实验数据转化为阻力系数，因此本文也将计算结果按照相同方法转换为阻力系数进行对比。

 ${C_d} = \frac{{{F_d}}}{{\dfrac{\rho }{2}{{{v}}^2}{{A}}}} 。$ (8)

4 结　语

1）在船舶数值模拟过程中，数值计算精确度并不是随着网格密度的增大而增大，但是随着计算区域的增加，网格密度对计算结果的影响减小。可以适当地采用较大的计算区域和较小的网格密度，以节省计算时长。对于和本文相似的散货船，推荐网格基础尺寸为0.14，计算区域为6倍船长，并采用SST K-Omega湍流模型。

2）采用经验公式法计算和本文船型相似的船舶静水阻力时，建议采用桑海公式可取得更高精度。

3）采用30 000 t散货船以及KCS船，对本文提出的数值计算策略进行验证分析，实验误差均在5%以内，满足实际的工程需求。

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