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Entropy production analysis of hysteresis characteristic of a pump-turbine model

机译：水轮机模型磁滞特性的熵产分析

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摘要

The hydraulic loss due to friction and unstable flow patterns in hydro-turbines causes a drop in their efficiency. The traditional method for analyzing the hydraulic loss is by evaluating the pressure drop, which has certain limitations and cannot determine the exact locations at which the high hydraulic loss occurs. In this study, entropy production theory was adopted to obtain a detailed distribution of the hydraulic loss in a pump-turbine in the pump mode. In the past, the wall effects of entropy production were not considered, which caused larger errors as compared with the method of pressure difference. First, a wall equation was proposed to calculate the hydraulic loss in the wall region. The comparison of hydraulic loss calculated by entropy production and pressure difference revealed a better result. Then, through the use of the entropy production theory, the performance characteristics were determined for a pump-turbine with 19 mm guide vane opening, and the variation in the entropy production was obtained. Recently, an interesting phenomenon, i.e., a hysteresis characteristic, was observed in the hump region in pump turbines. Research shows that the hysteresis characteristic is a result of the Euler momentum and hydraulic loss; the hydraulic loss accounts for a major portion of the hysteresis characteristic. Finally, the hysteresis characteristic in the hump region was analyzed in detail through the entropy production. The results showed that the hump characteristic and the accompanying hysteresis phenomenon are caused by backflow at the runner inlet and the presence of separation vortices close to the hub and the shroud in the stay/guide vanes, which is dependent on the direction of discharge. (C) 2017 Elsevier Ltd. All rights reserved.
机译：水轮机中由于摩擦和不稳定的流型导致的水力损失会导致其效率下降。用于分析水力损失的传统方法是通过评估压降，这种方法具有一定的局限性，无法确定发生高水力损失的确切位置。在这项研究中，采用熵产生理论来获得泵模式下水轮机中水力损失的详细分布。过去，没有考虑熵产生的壁效应，与压差法相比，这会引起更大的误差。首先，提出了一个壁方程来计算壁区域的水力损失。通过熵产生和压力差计算的水力损失的比较显示出更好的结果。然后，通过使用熵产生理论，确定了导叶开口为19 mm的水泵水轮机的性能特征，并得出了熵产生的变化。最近，在水泵水轮机的驼峰区域观察到一种有趣的现象，即磁滞特性。研究表明，磁滞特性是欧拉动量和水力损失的结果。水力损失占磁滞特性的主要部分。最后，通过熵的产生来详细分析驼峰区域的磁滞特性。结果表明，驼峰特性和伴随的滞后现象是由流道入口处的回流以及分离旋涡的存在引起的，该分离旋涡的位置靠近轮毂和导流罩的导流罩，这取决于排放方向。 （C）2017 Elsevier Ltd.保留所有权利。

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  • 来源
    《Energy Conversion & Management》 |2017年第10期|175-191|共17页
  • 作者

    Li Deyou; Wang Hongjie; Qin Yonglin; Han Lei; Wei Xianzhu; Qin Daqing;

  • 作者单位

    Harbin Inst Technol, Sch Energy Sci & Engn, Harbin 150001, Heilongjiang, Peoples R China;

    Harbin Inst Technol, Sch Energy Sci & Engn, Harbin 150001, Heilongjiang, Peoples R China;

    Harbin Inst Technol, Sch Energy Sci & Engn, Harbin 150001, Heilongjiang, Peoples R China;

    Harbin Inst Technol, Sch Energy Sci & Engn, Harbin 150001, Heilongjiang, Peoples R China;

    Harbin Inst Technol, Sch Energy Sci & Engn, Harbin 150001, Heilongjiang, Peoples R China|Harbin Inst Large Elect Machinery, State Key Lab Hydropower Equipment, Harbin 150040, Heilongjiang, Peoples R China;

    Harbin Inst Technol, Sch Energy Sci & Engn, Harbin 150001, Heilongjiang, Peoples R China|Harbin Inst Large Elect Machinery, State Key Lab Hydropower Equipment, Harbin 150040, Heilongjiang, Peoples R China;

  • 收录信息 美国《科学引文索引》(SCI);美国《工程索引》(EI);
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

    Pump-turbine; Entropy production; Hysteresis characteristic; Hydraulic loss; Backflow;

    机译：水泵水轮机;熵产生;磁滞特性;水力损失;回流;

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