航行体不同角度入水的空泡流体特性研究

Research on the characteristics of cavity fluid at different angles of the vehicle

为研究航行体不同俯仰角入水空化演变规律及空泡流体特性,基于Realizable k-ε湍流模型和VOF多相流模型,建立航行体不同俯仰角入水数值模型,开展数值方法验证,数值模拟结果与实验测试结果吻合。基于此,研究航行体入水空化过程演变机理及其不同俯仰角水空泡内流体分布规律和空化阶段演变特性。研究结果表明,依据空泡内流体分布变化规律空化过程可分为空泡的表面闭合阶段、饱和阶段、深度闭合阶段和溃灭阶段;在入水速度一定的情况下随航行体入水俯仰角增大空泡生成速率降低、空泡内的水蒸汽体积增长率减小、水蒸汽体积含量峰值变小、空泡饱和阶段的空气体积变大,体积范围为6%~9%;空泡表面闭合无量纲时间随入水俯仰角从-10°变化到10°呈对数趋势增长,空泡饱和无量纲时间近似线性递减,空泡深度闭合无量纲时间基本不受俯仰角变化影响。

A numerical simulation method was established based on the Realizable k-εturbulence model and the VOF multiphase flow model to study the evolution of the cavitation law and the characteristics of the cavity fluid at different pitch angles of the vehicle.A numerical model of the vehicle entering the water at different pitch angles was established,and the verification of the numerical method was carried out,and the numerical simulation results agreed with the experimental test results.On this basis,the evolution mechanism of the cavitation process of the vehicle into the water and its fluid distribution law and cavitation stage evolution characteristics in the cavity at different pitch angles are studied.The results show that the cavitation process can be divided into surface closure,saturation,deep closure and collapse stages of the cavity according to the change of fluid distribution in the cavity.In the case of a certain speed of water entry with the vehicle into the water pitch angle increases the rate of cavity generation decreases,the growth rate of water vapor volume in the cavity decreases,the peak water vapor volume content becomes smaller,and the volume of air in the saturation phase of the cavity becomes larger.Cavity surface closure dimensionless time grows logarithmically with the change of pitch angle from-10°to 10°,cavity saturation dimensionless time decreases approximately linearly,and cavity depth closure dimensionlesstime is basically not affected by the change of pitch angle.