[论文解读] Numerical investigation of unsteady flow in a reversible pump-turbine

Chirag Trivedi|arXiv (Cornell University)|Jan 23, 2026

Cavitation Phenomena in Pumps被引用 0

一句话总结

本研究建立了高保真 CFD 模型用于研究模仿泵汽轮机在涡轮和泵送模式下的非定常流动，揭示了复杂的频率分量和Dean涡旋效应。并报告了验证误差与关键流动现象，包括潜在的共振风险。

ABSTRACT

Hydropower is an important source of renewable energy that provides clean energy. Pump-turbine type hydraulic turbine is widely used to mitigate the intermittent energy demand and store a large-scale energy. Pump-turbine operates in reverse mode in pump mode to store energy. Flow conditions in turbine mode and pump mode operations is substantially different. This study investigates the unsteady flow field in the model pump-turbine. A computational model of the pump-turbine was created, and the model included hexahedral mesh of 58.19 million nodes. Total verification and validation error was 7.7%. Three operating conditions in turbine mode and four in pump mode were simulated. Flow characteristics, such as blade loading, time-dependent pressure fluctuations, frequency spectra, radial and tangential velocity were investigated. The frequency spectra revealed amplitude of frequencies up to tenth harmonics of the blade passing frequency in pump mode. The higher harmonic frequencies can potentially reach the high mode eigen frequencies and increase the risk of resonance. Flow field analysis in the draft tube indicted the strong presence of Dean vortices causing highly asymmetric flow at the runner inlet in pump mode operation. This study provides essential insights into the complex flow phenomena and advances the understanding of unsteady flow behaviour in pump-turbines.

研究动机与目标

• 通过解决用于储能和负载平衡的泵汽轮机装置中理解非定常流动的需求来推动研究。
• 开发具有详细网格的可逆泵汽轮机计算模型，以捕捉非定常流动现象。
• 表征在涡轮和泵送工作模式下的流动特征，如叶片载荷、压力波动和速度场。

提出的方法

• 创建包含 58.19 百万节点的六边形网格的泵汽轮机 CFD 模型。
• 对三种涡轮模式工况和四种泵模式工况进行数值模拟，以研究非定常流动。
• 分析随时间变化的压力、叶片载荷、速度场和频率谱，识别高阶叶片通过频率等谐波成分。
• 通过验证与确认评估模型精度，总误差报道为 7.7%。
• 识别如导向管内的 Dean 涡旋等流动现象对进口流动对称性的影响。

实验结果

研究问题

• RQ1 可逆泵汽轮机的涡轮模式和泵送模式中会出现哪些非定常流动特征？
• RQ2 在选定工况下，压力波动与速度场如何随时间演化？
• RQ3 流动波动的频谱成分是什么，高阶谐波是否接近共振模态？
• RQ4 如 Dean 涡旋等流动结构对转轮进口处的流动对称性有何影响？

主要发现

• 频谱中在泵送模式下的振幅可达到叶片通过频率的十次谐波量级。
• 高阶谐波可能达到高模态的特征频，显示潜在的共振风险。
• Dean 涡旋在导流管中表现显著，泵模式运行时转轮进口处的流动高度不对称。
• 计算模型的总验证/确认误差为 7.7%。
• 在多工况下分析了叶片载荷、随时间变化的压力波动以及径向/切向速度等流动特征。