Abstract In this paper, the cavitating flow and pressure fluctuation in the tip region were simulated based on Delayed Detached Eddy Simulation (DDES). The high-speed photography and transient pressure measurements were employed to capture the cavitation structures and pressure fluctuation. The numerical results show a reasonable agreement with the available experiments. The maximum errors of head and efficiency are 2.9% and 2.2%. The impeller rotation dominants the tip pressure field, with some obvious high-frequency components induced by the cavitating flow. Increasing the flow rate from 0.8Qopt to 1.2Qopt, the amplitudes of the frequency domain in P2 decrease from 0.13 to 0.08. There are more harmonic-frequency components at 0.8Qopt, including 5BPF, 6BPF, 7BPF. Suction-side-perpendicular cavitating vortices (SSPCVs) appeared in severe cavitation conditions, which leads to the collapse of the triangular cavitation cloud. The spatial-temporal evolution of SSPCV was divided into three stages: Generating stage, Shedding stage, and Dissipating stage. The pressure fluctuates significantly in the flow passage caused by SSPCV. The amplitudes of dominant frequency in P3 vary from 0.031 to 0.089, as the cavitation number decreased from 0.582 to 0.231. In particular, there is an obvious low-frequency N∗ = 0.5 shown in the frequency domains of P2 and P3.

中文翻译：

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叶尖泄漏涡诱导空化流对轴流泵压力波动影响的实验和数值研究

摘要 本文基于延迟分离涡模拟(DDES)方法对尖端区域的空化流动和压力脉动进行了模拟。采用高速摄影和瞬态压力测量来捕捉空化结构和压力波动。数值结果表明与可用实验的合理一致性。扬程和效率的最大误差分别为2.9%和2.2%。叶轮旋转主导着叶尖压力场，一些明显的高频分量由空化流引起。将流速从 0.8Qopt 增加到 1.2Qopt，P2 中频域的幅度从 0.13 减小到 0.08。0.8Qopt处的谐波分量较多，包括5BPF、6BPF、7BPF。吸入侧垂直空化涡流（SSPCVs）出现在严重空化条件下，导致三角形空化云坍塌。SSPCV 的时空演化分为三个阶段：生成阶段、脱落阶段和消散阶段。由 SSPCV 引起的流道中的压力波动很大。随着空化数从 0.582 减少到 0.231，P3 中主频率的幅度从 0.031 变化到 0.089。特别是在P2和P3的频域中出现了明显的低频N∗=0.5。由 SSPCV 引起的流道中的压力波动很大。随着空化数从 0.582 减少到 0.231，P3 中主频率的幅度从 0.031 变化到 0.089。特别是在P2和P3的频域中出现了明显的低频N∗=0.5。由 SSPCV 引起的流道中的压力波动很大。随着空化数从 0.582 减少到 0.231，P3 中主频率的幅度从 0.031 变化到 0.089。特别是在P2和P3的频域中出现了明显的低频N∗=0.5。