Suppressing the Vortex Rope Oscillation and Pressure Fluctuations by the Air Admission in Propeller Hydro-Turbine Draft Tube

IF 1.1 4区工程技术 Q4 MECHANICS

Journal of Applied Fluid Mechanics Pub Date : 2024-01-01 DOI:10.47176/jafm.17.1.1994

H. Wu, F. Jin, Y. Luo, Y. Ge, Q. Wei, C. Zeng, X. Liu, W. Zhang, D. Miao, H. Bai

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引用次数: 0

Abstract

For the purpose of automatic generation control (AGC), a portion of the propeller hydro-turbine units in China is adjusted to operate within a restricted range of 75%-85% load using computer-controlled AGC strategies. In engineering applications, it has been observed that when a propeller hydro-turbine unit operates under off-design conditions, a large-scale vortex rope would occur in the draft tube, leading to significant pressure fluctuations. Injecting air into the draft tube to reduce the amplitude of pressure fluctuations is a common practice, but its effectiveness has not been proven on propeller hydro-turbine units. In this study, a CFD model of a propeller hydro-turbine was established, and 15 cases with different guide vane openings (GVO, between 31° and 45°) under unsteady conditions were calculated and studied. Two air admission measures were introduced to suppress the vortex rope oscillation in the draft tube and to mitigate pressure fluctuations. The reason for the additional energy loss due to air admission was then explained by the entropy production theory, and its value was quantified. This study points out that when injecting air, it is necessary to first consider whether the air will obstruct the flow in the draft tube. Finally, based on simulation and experimental data under various load conditions, pressure fluctuation analysis (based on fast Fourier transform, FFT) was conducted to assess the effectiveness of air admission measures. This study can provide an additional option for balancing unit efficiency and stability when scheduling units using an AGC strategy.

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利用螺旋桨水轮机引水管的进气量抑制涡绳振荡和压力波动

为了实现自动发电控制（AGC）的目的，中国的部分螺旋桨水轮机组采用计算机控制的 AGC 策略，在 75%-85% 的限制负荷范围内运行。在工程应用中观察到，当螺旋桨水轮机组在非设计条件下运行时，牵伸管内会出现大规模涡绳，导致压力大幅波动。向牵伸管内注入空气以减小压力波动幅度是一种常见的做法，但其有效性尚未在螺旋桨水轮机组上得到证实。本研究建立了螺旋桨水轮机的 CFD 模型，并计算和研究了在非稳定条件下不同导叶开度（GVO，31° 至 45°）的 15 种情况。引入了两种进气措施，以抑制牵伸管中的涡绳振荡并减缓压力波动。然后用熵产生理论解释了由于空气进入而导致额外能量损失的原因，并量化了其值。这项研究指出，在注入空气时，有必要首先考虑空气是否会阻碍牵伸管中的流动。最后，根据各种负载条件下的模拟和实验数据，进行了压力波动分析（基于快速傅立叶变换，FFT），以评估空气接纳措施的有效性。在使用 AGC 策略对机组进行调度时，这项研究可为平衡机组效率和稳定性提供额外的选择。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Journal of Applied Fluid Mechanics THERMODYNAMICS-MECHANICS

CiteScore

2.00

自引率

20.00%

发文量

138

审稿时长

>12 weeks

期刊介绍： The Journal of Applied Fluid Mechanics (JAFM) is an international, peer-reviewed journal which covers a wide range of theoretical, numerical and experimental aspects in fluid mechanics. The emphasis is on the applications in different engineering fields rather than on pure mathematical or physical aspects in fluid mechanics. Although many high quality journals pertaining to different aspects of fluid mechanics presently exist, research in the field is rapidly escalating. The motivation for this new fluid mechanics journal is driven by the following points: (1) there is a need to have an e-journal accessible to all fluid mechanics researchers, (2) scientists from third- world countries need a venue that does not incur publication costs, (3) quality papers deserve rapid and fast publication through an efficient peer review process, and (4) an outlet is needed for rapid dissemination of fluid mechanics conferences held in Asian countries. Pertaining to this latter point, there presently exist some excellent conferences devoted to the promotion of fluid mechanics in the region such as the Asian Congress of Fluid Mechanics which began in 1980 and nominally takes place in one of the Asian countries every two years. We hope that the proposed journal provides and additional impetus for promoting applied fluids research and associated activities in this continent. The journal is under the umbrella of the Physics Society of Iran with the collaboration of Isfahan University of Technology (IUT) .