螺旋桨空化仿真相关模型比较研究

Comparative study on related models of propeller cavitation numerical simulation

[目的]旨在研究空化模型对实尺度螺旋桨空化模拟结果的影响。[方法]运用伯努利方程预测螺旋桨空化发生时的转速,通过实船试验观察螺旋桨空化状况;采用CFD数值仿真螺旋桨空化状态,确定仿真中边界层网格厚度并在建立水动力模型后生成网格;模拟时的湍流模型分别选择标准k-ε模型,空化模型分别选择Schnerr–Sauer(S–S)和Zwart–Gerber–Belamri(ZGB)模型;追踪记录螺旋桨表面最大气体体积分数并观察其气体分布情况,将数值仿真结果与试验结果对比,比较两种空化模型的模拟精度。[结果]结果表明,相较于标准贴合。对螺旋桨表面最大气体体积分数进行监测,发现湍流模型的选择对空化剧烈程度的影响不大,而使用S–S模型的结果明显高于ZGB模型。[结论]研究表明,湍流模型对空化区域面积有较大影响,空化模型对空化的剧烈程度有较大影响,对螺旋桨空化仿真而言,Realizable k-ε湍流模型的模拟精度高于标准k-ε模型。

[Objective]The purpose of this paper is to study the effects of cavitation models on the simula-tion of full-scale propeller cavitation.[Methods]The minimum rotational speed of the propeller required for cavitation is predicted by the Bernoulli equation,and the propeller's cavitation condition is observed by full-scale experiment.After determining the boundary layer mesh thickness and establishing the hydrodynamic model,meshes are generated.In the numerical simulation,the turbulence model is selected from either the standard k-ε model or Realizable k-ε model,and the cavitation model is selected from either the Schnerr-Sauer(S-S)model or the Zwart-Gerber-Belamri(ZGB)model.The maximum gas volume fraction on the surface of the propeller is tracked and recorded.In the meantime,the reliability of the numerical simulation is evaluated by observing the gas distribution on the surface of the propeller.And the simulation accuracy of the k-εrelated models is compared.[Results]The simulation results show that compared with the standard k-εturbulence model,the cavitation region obtained with the Realizable model is significantly more consist-ent with the experimental results.By monitoring the maximum gas volume fraction on propeller's surface,it is found that the choice of turbulence model has little effect on the cavitation intensity,and the cavitation intens-ity obtained by S-S model is significantly higher than that obtained by the ZGB model.[Conclusions]This study shows that the turbulence model has a great influence on the area of the cavitation region,and cavitation models have a great influence on cavitation intensity.In terms of the simulation of propeller cavitation,the accuracy of the Realizable k-ε model is higher than that of the standard k-ε model.