Theoretical, experimental, and numerical study of special impeller used in turbine mode of centrifugal pump as turbine
Theoretical, experimental, and numerical study of special impeller used in turbine mode of centrifugal pump as turbine
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离心泵涡轮模式专用叶轮作为涡轮的理论、实验和数值研究
DOI：
10.1016/j.energy.2017.04.156
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发表时间：
2017-07-01
期刊：
影响因子：
9
通讯作者：
Yang, Sunsheng
中科院分区：
文献类型：
--
作者：
Wang, Tao;Wang, Chuan;Yang, Sunsheng
传统的后向曲线离心式叶轮与水轮机运行状态不匹配，限制了泵-水轮机技术的发展，但其性能不佳，效率范围较窄。本研究旨在通过设计一种适用于透平工况的具有前弯叶片的特殊叶轮，并研究在能量转换中起重要作用的叶片进、出口角度的确定方法，来显著提高PAT的性能。对所设计的特殊叶轮和原设计的后掠叶轮进行了性能试验。用经过验证的计算流体力学技术对不同叶轮的比转速为18.1的PATS进行了数值研究，证明了用特殊叶轮替换原叶轮后的性能得到了改善。通过对另外两台离心泵中的另外两个特殊叶轮的设计和试验，验证了所提出的方法对其他情况的适用性。与原后弯叶轮相比，三种不同比转速的特殊前弯叶轮的实验最大效率均有较大幅度的提高，流动效率曲线更加平坦，说明前弯叶轮在PAT中具有明显的优越性。最佳效率点(BEP)的实验流量与理论设计流量非常接近，表明叶片进口角度与设计流量之间的理论关系式为PAT的特殊叶轮涡轮运行方式下的BEPS流量提供了一种有效的预测方法。本研究提供了一种低成本、便捷的方式来显著提高涡轮模式下的PAT效率。(C)2017爱思唯尔有限公司。保留所有权利。
The pump-as-turbine (PAT) technique is limited by its undesirable performance and narrow range of high efficiency due to the mismatch between the conventional backward-curve centrifugal impellers and the turbine running condition. This study aims to significantly improve the performance of PAT by designing a special impeller with forward-curve blades for the turbine working condition, and investigating the method for determining the blade inlet and outlet angles that play important roles in the energy conversion. The performance tests of PATs with the designed special impeller and an original backswept blade impeller were performed. The improved performance after replacing the original impeller with the special impeller was demonstrated by numerically investigating the PATs of specific speed of 18.1 with different impellers by use of a verified computational fluid dynamics technique. The suitability of the proposed methods to other cases was verified by designing and experimenting on two other special impellers used in two other centrifugal pumps as turbines with various specific speeds. Compared with the original backward-curve impellers, the experimental maximum efficiencies of special forward-curve impellers of three various specific speeds are more significantly increased and the flow efficiency curve is flatter, suggesting the obvious superiority of the forward-curve impeller in PAT. The experimental flow rate of best efficiency point (BEP) is very close to the theoretically designed flow rate, indicating that the theoretical relationship expression between the blade inlet angle and design flow rate provides an effective prediction method of BEPs' flow rate in PAT's turbine operating mode with special impeller. A low-cost and convenient way to significantly improve the efficiency of PAT in turbine mode is provided in this study. (C) 2017 Elsevier Ltd. All rights reserved.