Purpose

Tip leakage vortex flow (TLV) is a common flow phenomenon in the axial-flow hydraulic machinery. High-efficiency simulation of TLV is still not an easy task because of the complex turbulent vortex-cavitation interactions. As an important basis of CFD, turbulence model directly affects the efficient computation of TLV. The purpose of this paper is to evaluate the newly developed MST turbulence model in predicting the TLV flows.

Design/methodology/approach

By using the MST turbulence model and the ZGB cavitation model, numerical simulations of the TLV generated by a NACA0009 hydrofoil were performed under the cavitation-free and cavitation conditions, and the results were compared with the available experimental data.

Findings

The important features of TLV are well captured by the MST-based simulation scheme, and the problem of under-predicting the cavitating TLV tube is well solved. Turbulent viscosity is reasonably adjusted in the TLV core regions, and the LES-like mode is activated, which is beneficial to obtain more turbulent information on the same URANS grids. The requirements of grid size and time step of the MST model are much lower than that of the LES method, thereby weighing a good balance between the simulation accuracy and computation cost.

Originality/value

The MST turbulence model is suitable for the high-efficiency simulation of the TLV flows, which can lay a good foundation for efficient engineering computations of the cavitating TLV in the axial-flow hydraulic machinery.

中文翻译：

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MST湍流模型在预测尖端泄漏涡流中的应用

目的

尖端泄漏涡流（TLV）是轴流液压机械中的一种常见流动现象。由于复杂的湍流涡流-空化相互作用，TLV的高效仿真仍然不是一件容易的事。作为CFD的重要基础，湍流模型直接影响TLV的有效计算。本文的目的是评估在预测TLV流量方面最新开发的MST湍流模型。

设计/方法/方法

通过使用MST湍流模型和ZGB空化模型，在无空化和空化条件下，对由NACA0009水翼产生的TLV进行了数值模拟，并将结果与​​可用的实验数据进行了比较。

发现

基于MST的仿真方案很好地捕获了TLV的重要特征，很好地解决了空化TLV管预测不足的问题。在TLV核心区域合理地调整了湍流粘度，并激活了类似LES的模式，这有利于在相同的URANS网格上获得更多的湍流信息。MST模型的网格大小和时间步长要求比LES方法低得多，从而在仿真精度和计算成本之间取得了良好的平衡。

创意/价值

MST湍流模型适用于TLV流动的高效仿真，这可以为轴流式液压机械中空化TLV的高效工程计算奠定良好的基础。