Abstract:A transport equationbased cavitation model was developed according to the homogeneous assumption in this paper.The mechanism of evaporation and condensation was considered in the model.The noncondensable gas was also taken into account in cavity formation and development.The RNG turbulence model was employed with a modified turbulent viscosity according to the mixed density.The proposed model was implemented to simulate the steady cavitating flow around a NACA66 airfoil.The pressure coefficient distributions on the suction side of the foil agreed well with the experiment results.Furthermore,the effects of noncondensable gas,inlet turbulent kinetic energy and turbulence dissipation rate on the cavity length were evaluated.The proper values of noncondensable gas,inlet turbulent kinetic energy and turbulence dissipation were selected.Then,the proposed model was applied to an unsteady cavitating flow.The numerical results clearly reflected the whole process of the cavitationcloud generation,growth,dispersion and collapse.The simulation showed re-entrant jet is one of the main reasons for the breakoff process.The Strouhal number obtained agreed well with the experiment results.The overall results prove the reliability of the proposed model in cavitating flow simulations.
宋宇, 曹树良. 考虑不可凝结气体的空化流模型及数值模拟[J]. 排灌机械工程学报, 2012, 30(1): 1-5.
SONG Yu,CAO Shu-Liang. Cavitation model with noncondensable gas effect and its numerical simulation. Journal of Drainage and Irrigation Machinery Engin, 2012, 30(1): 1-5.
参考文献(References)[1]Asnaghi A,Jahanbakhsh E,Seif M S.Unsteady multiphase modeling of cavitation around NACA0015[J].Journal of Marine Science and Technology,2010,28(5):689-696.[ZK)][2]谭磊,曹树良.基于滤波器湍流模型的水翼空化数值模拟[J].江苏大学学报:自然科学版,2010,31(6):683-686.Tan Lei,Cao Shuliang.Numerical simulation of hydrofoil cavitation based on filterbased model[J].Journal of Jiangsu University:Natural Science Edition,2010,31(6):683-686.(in Chinese)[3]谭磊,曹树良,桂绍波,等.绕水翼空化流动的数值模拟[J].清华大学学报:自然科学版,2010,50(7):1058-1062.Tan Lei,Cao Shuliang,Gui Shaobo,et al.Numerical simulation of cavity flow around a hydrofoil[J].Journal of Tsinghua University:Science and Technology,2010,50(7):1058-1062.(in Chinese)[4]Huang Biao,Wang Guoyu,Yuan Haitao Y.A cavitation model for cavtating flow simulations[J].Journal of Hydrodynamics,2010:22(1):756-762.[5]Morgut M,Nobile E,BiluI.Comparison of mass transfer models for the numerical prediction of sheet cavitation around a hydrofoil[J].International Journal of Multiphase Flow,2011:37(6):620-626.[6]谭磊,曹树良.中比转速离心泵叶轮的优化设计及数值模拟[J].排灌机械工程学报,2010,28(4):282-285.Tan Lei,Cao Shuliang.Optimal design and numerical simulation for impeller of centrifugal pump with mediumhigh specific speed[J].Journal of Drainage and Irrigation Machinery Engineering,2010,28(4):282-285.(in Chinese)[7]谭磊,曹树良,桂绍波,等.带有前置导叶离心泵空化性能的试验及数值模拟[J].机械工程学报,2010,46(18):177-182.Tan Lei,Cao Shuliang,Gui Shaobo,et al.Experiment and numerical simulation of cavitation performance for centrifugal pump with inlet guide vane[J].Journal of Mechanical Engineering,2010,46(18):177-182.(in Chinese)[8]Yamaguchi.Cloud cavitation on foil sections [C]∥Proceedings of the 6th International Symposium on Cavitation.Wageningen:the Netherlands,2006:1-2.[9]Kubota A,Kuto H,Yamaguchi H.A new modeling of cavitating flows:A numerical study of unsteady cavitation on a hydrofoil section[J].Journal of Fluid Mechanics,1992,240:59-96.[10]Shen Y T,Dimotakis P E.The influence of surface cavitation on hydrodynamic forces [C]∥Proceedings of the 22nd American Towing Tank Conference.Canada:St.John′s,1989:44-52.