对不同空化模型的比较研究

目前关于水工建筑物中的空蚀破坏力的研究主要采用模型试验和数值分析手段,而在数值分析中多采用空化模型进行研究,空化模型的选择对于空化流动的计算有着重要的影响。基于Rayliegh-Plesset方程的空化模型有着广泛的应用,其中比较有代表性的有SchnerrSauer、Singhal及Zwart等空化模型,文章应用这3种空化模型对方头体的空化流动现象进行了定常和非定常数值模拟,其中紊流模型采用sst k-ω模型,并结合商业软件中的UDF方法 (用户自定义函数)对其黏性进行了修正。计算表明,Zwart、SchnerrSauer模型比Singhal空化模型具有更好的鲁棒性,且可观察到明显的空泡运动;SchnerrSauer模型得到的壁面压力系数分布和实验值最为接近;而Singhal模型在非定常计算中,能够获得由质量空化源周期性变化引起的周期性相变过程。

Comparison and Study on Different Cavitation Models

Currently, model test and value analysis are the main means for the study of the cavitation failure force in the hydraulic structures.In the value analysis, the cavitatio model is mostly applied.Selection of the cavitation model largely impacts calculation of cavitation flowing.The cavitation model based on Rayliegh-Plesset equation is widely applied.Among the cavitation models, the representative ones are Schnerr ＆amp;Sauer, Singhal and Zwart.In the paper, the three models above mentioned are applied to simulate, in steady-state and non-steady-state values, the cavitation flowing phenomenon of the square body.The flow model applies sst k-ωmodel.In combination with UDF （user defines function） method in commercial software, the model viscosity is corrected.The calculation shows that robustness of Zwart, Schnerr and Sauer models are better than that of Singhal model.Furthermore, the obvious air bubble movement can be seen.Distribution of the pressure coefficient of the wall surface from Schnerr and Sauer models is most close to the experimental value.In the non-steady-state calculation, the periodic phase variation process caused by the periodic variation of the quality cavitation source can be obtained by Singhal model.