ABSTRACT

The primary objective of this research is to study the cavitating effects of fluid flow past different axisymmetric cavitator in the upper sub-critical flow regime, which corresponds to the Reynolds number (2 × 10⁴ to 2 × 10⁵). Experiments are conducted in a water tunnel with a fluid flow velocity of 30 to 60 m/s at a constant rate of injection. The commercial software tool, ANSYS Fluent 18.1, is used to simplify three dimensional Reynolds averaged Navier Stokes equation with the compressible fluid flow by considering the pressure-based solver with standard k–ϵ turbulence model. A comparison of the numerical and experimental results shows that the numerical method can predict accurately the shape parameters of the natural cavitation phenomena such as cavity length, cavity diameter, and cavity shape. Results reported that with an increase in velocity, the cavity length and diameter increased to 250% and 20% respectively.

摘要

本研究的主要目的是研究流体流过不同轴对称空化器在上部亚临界流动状态下的空化效应，这对应于雷诺数（2 × 10 ⁴到 2 × 10 ⁵）。实验在流体流速为 30 至 60 m/s 的水隧道中以恒定的注入速率进行。商业软件工具 ANSYS Fluent 18.1 用于通过考虑具有标准k-ε的基于压力的求解器来简化具有可压缩流体流动的三维雷诺平均 Navier Stokes 方程湍流模型。数值与实验结果对比表明，数值方法能够准确预测自然空化现象的空腔长度、空腔直径、空腔形状等形状参数。结果表明，随着速度的增加，空腔长度和直径分别增加到 250% 和 20%。