叶轮
围带
尾水管
机械
涡流
流量(数学)
涡轮机
流动分离
体积流量
比转速
内部流动
入口
螺杆泵
材料科学
地质学
物理
工程类
变量泵
湍流
机械工程
离心泵
径向柱塞泵
作者
Fei Zhang,Zhenmu Chen,Shuangqian Han,Baoshan Zhu
出处
期刊:Processes
[MDPI AG]
日期:2023-12-22
卷期号:12 (1): 41-41
被引量:1
摘要
Extensive research has been conducted on the performance of pump turbines, particularly focused on understanding the generation mechanism of S-shaped characteristics. However, there has been a lack of research on unsteady flow characteristics in hump characteristics with small guide vane openings. This study focuses on the hump characteristics of a pump turbine in pump mode. The unsteady numerical simulation method is used along with experimental testing to examine the internal flow characteristics and induced pressure fluctuations under pump operating conditions. The results indicate that flow separation occurs in the impeller when the flow rate decreases to the valley operating condition, and recirculation flow occurs near the impeller inlet at the partial flow rate. Moreover, the unstable flow on the positive slope exhibits a low-frequency characteristic of 0.15fn. The pressure fluctuation from the hub to shroud areas of the guide vane region diminishes sequentially. Notably, distinct vortex structures emerge at the draft tube cone section under the valley operating condition. These structures extend toward the elbow section of the draft tube as the flow rate decreases. This phenomenon generates low-frequency pressure fluctuation originating from the primary frequency of the vortex and dean vortex on the surface, located at 0.4 D of the draft tube under conditions of low flow rate.
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