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Study of the numerical simulation method for unsteady cavitating flow

非定常空泡流数值模拟方法研究

基本信息

批准号：
13650180
负责人：
KAJISHIMA Takeo
金额：
$ 2.56万
依托单位：
Osaka University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2001
资助国家：
日本
起止时间：
2001 至 2003
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-13650180/
关键词：
Cavitation Numerical simulation Cascade Gas-liquid two phase flow Unsteady flow Phase change Computational Fluid Dynamics 数値流体力学リエントラントジェット

项目摘要

Cogitating flows in cascades contain wide variety of physics, ranging from microscopic bubble dynamics to macroscopic unsteady flow. Thus experimental or theoretical analysis of such two-phase flows contains difficulties. Recently, numerical investigation is expected to become a reasonable tool, especially for application in industry. An objective of this study is to construct a practical method to analyze unsteady and unstable phenomena in cascade flow. In FY2001, we proposed a modified cavitations model based on Chen's method to deal with macroscopic flow field with unsteady cavitations and applied it to three-dimensional computation. As a result, characteristic structure such as interaction between re-entrant jet and cloud cavitations was reasonably reproduced. In FY2002, the reliability of our method was improved. Namely, the accuracy and robustness of low Mach-number assumption method and the conservation properties of non-reflection boundary condition were particularly considered. In addition, the analysis of interactive phenomena of cavitation among flow passages in two-dimensional cascade was started. In FY2003, some improvements for computational model were continued. For instance, new sub-grid scale turbulence model for the large eddy simulation (LES) on generalized curvilinear coordinate system was developed. Although it was not combined to the cavitation analysis in the term of this project, we believe it is hopeful for next development. As for the two-dimensional simulation, the two propagation modes due to the rotating cavitation and the flow separation were successfully reproduced and the result confirmed the adequacy of our method.

叶栅中的共格流动包含了从微观气泡动力学到宏观非定常流动的各种物理现象。因此，这种两相流的实验或理论分析包含困难。近年来，数值研究有望成为一种合理的工具，特别是在工业应用中。本研究的目的是建立一个实用的方法来分析叶栅流动中的非定常和不稳定现象。2001年，我们在Chen方法的基础上提出了一种改进的空化模型，用于处理含非定常空化的宏观流场，并将其应用于三维计算。结果合理地再现了再入射流与云空泡相互作用等特征结构。在2002财政年度，我们的方法的可靠性得到了改善。即特别考虑了低马赫数假设方法的精度和鲁棒性以及无反射边界条件的守恒性。此外，还对二维叶栅流道间的空化交互作用现象进行了分析。在2003财政年度，继续对计算模型进行了一些改进。例如，在广义曲线坐标系下，发展了新的亚网格尺度湍流大涡模拟模型。虽然在本项目期间没有将其结合到空化分析中，但我们相信它是有希望进行下一步发展的。对于二维数值模拟，成功地再现了旋转空化和流动分离两种传播模式，验证了本文方法的有效性。