散货船纵倾减阻及其成因分析

Analysis of resistance change of bulk carriers trim optimization

船舶纵倾优化作为一种有效的节能减排技术已越发受到人们的关注。为了研究船舶纵倾优化过程中纵倾调整对船舶阻力变化的影响,采用计算流体力学方法(Fluent软件)运用RANS方程加VOF自由面模型的方法求解了180000DWT散货船在不同纵倾状态下的阻力数值和流场信息,将阻力计算结果与模型试验结果进行对比,验证数值计算的准确性。比较不同纵倾状态下阻力值,得到船舶设计状态阻力随纵倾变化规律。进一步运用Euler方程加VOF自由面模型的方法求得兴波阻力,总阻力减去兴波阻力即为粘性阻力,结合流场细节分析和比较,获得船舶纵倾优化过程中总阻力变化的主导因素。本文研究对于纵倾优化技术在散货船型上的应用具有积极的指导意义。

As an effective energy-saving and emission-reduction technology,ship trim optimization has attracted more and more attention.In order to study the influence of trim adjustment on the ship's resistance change during the ship's trim optimization process,the computational fluid dynamics method(Fluent software)was used to solve the 1800000DWT bulk carrier under different trim conditions by using the RANS equation and the VOF free surface model.The resistance value and flow field information are compared with the model test results to verify the accuracy of the numerical calculation.Comparing the resistance values under different trim conditions,the variation law of ship design state resistance with the pitch angle is obtained.Furthermore,the Euler equation and the VOF free surface model is used to obtain the wave resistance.The total resistance minus the wave resistance is the viscous resistance.Combined with the flow field detail analysis and comparison,the dominant factor of the total resistance change during the ship's trim optimization process is obtained..This paper has a positive guiding significance for the application of trim optimization technology in bulk carrier.