Investigation into Pump Mode Flow Dynamics for a Mixed Flow PAT with Adjustable Runner Blades

• Published in: Energies (Basel) 2021-05, Vol.14 (9), p.2690
• Main Authors: Binama, Maxime, Kan, Kan, Chen, Huixiang, Zheng, Yuan, Zhou, Daqing, Muhirwa, Alexis, Bwimba, Godfrey M.
• Format: Article
• Language: English
• Subjects: blade angle; Efficiency; Energy; Flow control; Flow stability; flow unsteadiness; Hydraulic turbines; Hydraulics; Hydroelectric plants; Intolerance; Investigations; Numerical analysis; numerical simulation; Pressure distribution; pressure pulsation; Pulsation; pump as turbine; Rotor stator interactions; Rotors; Simulation; Stators; System effectiveness; Turbines; Vortices; Water conveyance; Water supply; Water supply systems
• ISSN: 1996-1073; 1996-1073
• DOI: 10.3390/en14092690

The adoption of pumps as turbines (PATs) in both small-scale hydroelectric plants and water supply systems has brought about various advantages, the most recognized being cost-effectiveness compared to other hydroturbines. However, due to their lack of flow control ability, their intolerance to off-design operations constitutes a tough shortfall. Moreover, since this technology is new, PAT flow dynamics are not yet well understood. Therefore, this study intends to numerically investigate the mixed-flow PAT’s pump mode flow dynamics for five operating conditions from optimum (1 QBEP) to deep part-load (0.41 QBEP) conditions. Moreover, the effect of runner blade angle on them is investigated, considering three angles, namely −2°, 0°, and 2°. PAT flow stability was found to deteriorate as the flow decreased, where associated pressure pulsation level worsened at different flow zones. In addition, the blade angle increase led to correspondingly increasing flow unsteadiness and pressure pulsation levels, where the pulsation frequencies from rotor-stator interactions were dominant for most flow zones. This study’s findings are of crucial importance to both scientific and engineering communities as they contribute to a thorough understanding of PAT flow dynamics.