Numerical investigation of draft tube pressure pulsations in a Francis turbine with splitter blades

HYPERBOLE Symposium 2017 (HYdropower plants PERformance and flexiBle Operation towards Lean integration of new renewable Energies)

Kassanos, I.^1 ; Anagnostopoulos, J.^1 ; Papantonis, D.^1

Laboratory of Hydraulic Machines, School of Mechanical Engineering, National Technical University of Athens, Heroon Polytechneiou 9, Zografou, Athens

15780, Greece^1

关键词: Different operating conditions;    Helical vortices;    Improve performance;    Numerical investigations;    Part load conditions;    Pressure pulsation;    Pulsation frequency;    Unsteady characteristics;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/813/1/012049/pdf
DOI  :  10.1088/1742-6596/813/1/012049

来源: IOP

【 摘 要 】

Operation of Francis turbines at part load conditions is related to the appearance of the draft tube helical vortex rope. Splitter blades have been employed in high head Francis turbines in order to improve performance as well as their unsteady characteristics. In this work the draft tube unsteady characteristics of a Francis runner with splitter blades are investigated numerically. Two different splitter designs were analysed, and the performance results were compared to the baseline runner with no splitter blades used. The amplitude of pressure pulsation caused by the precessing vortex rope as well as the related frequency was compared for all cases, for two different operating conditions. From the results a relationship between the pulsation frequency and splitter blade geometry was observed.