考虑放大系数和速度滑移时泵反转液力透平性能换算关系研究

The key technology on a prediction and selection model for pump as turbine (PAT) is performance relationship between pump mode and turbine mode (Ht/Hp, Qt/Qp), While there is a large difference among these relations obtained by researchers, and it is difficult to apply. Based on the earlier research, amplification coefficient and slip factor were the reason that cause Ht/Hp, Qt/Qp large difference, however these were not considered for PAT prediction and selection in various researches. As a consequence, research on PAT performance relationship between pump mode and turbine mode in consideration of amplification coefficient and slip factor was presented. The method which combined theoretical investigation, CFD，PIV and experimental investigation was adopted. Slip mechanism of PAT be revealed and space-time evolution mechanism of slip be investigated. Slip factor be obtained next. Theoretical relation of amplification coefficient and Ht/Hp, Qt/Qp will be explained. PAT performance relationship between pump mode and turbine mode in consideration of amplification coefficient and slip factor will be established, and a prediction method for PAT be proposed ultimately. The project will lay the foundation for PAT design theory, while increase efficiency and operational stability for PAT.

泵工况与透平工况性能参数之间的换算关系Ht/Hp、Qt/Qp是泵反转液力透平（PAT）选型设计和性能预测的关键技术，但不同学者研究得到的换算结果差异较大，工程中难以应用。通过前期研究发现，引起PAT换算结果差异大的原因是：未考虑流量放大系数（比转速放大系数）和滑移系数对PAT性能换算关系的影响。据此提出了考虑放大系数和速度滑移时PAT性能换算关系的研究。拟采用理论分析、CFD数值模拟、PIV流场测试及外特性实验相结合的方法，揭示液力透平内部速度滑移机理，阐明速度滑移的时空演化机制，提出滑移系数的数学关系式；揭示流量放大系数（比转速放大系数）与PAT性能换算Ht/Hp、Qt/Qp之间的理论关系；最终建立考虑放大系数时，速度滑移约束条件下PAT泵工况与透平工况的性能换算关系，提出准确预测PAT性能的方法。为液力透平设计理论的发展和完善奠定基础，同时提高液体能量回收系统的效率和运行稳定性。

液力透平可回收生产生活中的液体余压能量，将液体压力能转换为旋转机械能加以利用，在石油化工、煤化工、海水淡化、钢铁冶金等工艺流程中有广泛应用。但工业应用发现，该装置存在选型不准、效率低、运行不稳定等问题。究其原因，液力透平内部流动机理不清，速度滑移、通道涡等特殊流动现象对能量转换及运行稳定性的影响未曾得知，这成为阻碍液力透平性能预测及优化设计的屏障。基于此，本项目开展了液力透平叶轮内速度滑移机理、考虑速度滑移与放大系数时泵反转透平性能换算关系等方面的研究。通过项目实施，建立了考虑速度滑移时泵反转液力透平泵工况与透平工况性能参数间的换算关系，揭示了速度滑移诱发的大尺度叶道涡特征与规律，提出了基于放大系数的低比转速泵反转透平性能换算关系修正方法。研究成果为液力透平选型、性能预测、优化设计等方面的理论研究及工程应用提供一定的理论依据。