A Study and Optimization of the Unsteady Flow Characteristics in the Last Stage Impeller of a Small-Scale Multi-Stage Hydraulic Turbine
A Study and Optimization of the Unsteady Flow Characteristics in the Last Stage Impeller of a Small-Scale Multi-Stage Hydraulic Turbine
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DOI：
10.3390/en17010107
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发表时间：
2023-12
期刊：
影响因子：
3.2
通讯作者：
Jun Yang;Tao Peng;Gang Xu;Wenli Hu;Huazhou Zhong;Xiaohua Liu
中科院分区：
文献类型：
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作者：
Jun Yang;Tao Peng;Gang Xu;Wenli Hu;Huazhou Zhong;Xiaohua Liu
由于节能减排的持续努力，对小型多级水轮机的需求正在快速增长。由于结构设计紧凑，这些涡轮机的内部流动结构更加复杂，容易产生低压区，导致气液两相流，并伴随着强烈的振动和噪声，从而对涡轮机运行的安全性和稳定性产生不利影响。同时，结合二维频域可视化技术和适当的正交分解，提出了一种创新的流场分析方法，建立了一个考虑频率分布、空间分布和能量贡献特征的旋转机械内部非定常流场结构诊断和优化框架。研究发现，在本研究条件下，存在两种主要的非定常流动结构，这两种结构是汽化风险较高的区域。根据分析的流动特性，提出了改进二次叶轮内两相流问题的优化方案，初步取得了满意的效果。
The demand for small-size multi-stage hydraulic turbines is experiencing rapid growth due to the ongoing efforts towards energy conservation and emission reduction. On account of their compact structural design, these turbines feature a more intricate internal flow configuration, rendering them prone to the creation of low-pressure zones, resulting in vapor–liquid two-phase flow, accompanied by the development of intense vibrations and noise, thereby adversely affecting the safety and stability of turbine operations. Concurrently, an innovative method for analyzing flow fields has been formulated combined with two-dimensional frequency domain visualization technology and proper orthogonal decomposition, serving to establish a diagnostic and optimization framework for the unsteady flow structures within rotating machinery by considering the features related to frequency distribution, spatial distribution, and energy contributions. It was found that there are two main unsteady flow structures which are the areas with high risks of vaporization under this study condition. According to the flow characteristics of the analysis, an optimization scheme was proposed to improve the two-phase flow problem in the secondary impeller, and the preliminary results were satisfactory.