Vortex and energy characteristics in the hump region of pump-turbines based on the rigid vorticity and local hydraulic loss method

Physics of Fluids, Год журнала: 2025, Номер 37(3)

Опубликована: Март 1, 2025

With the climate change hazards and implementation of pumped-storage hydropower units in power grid increases, maintaining hydraulic stability hump region is primordial for energy transition yet presents a significant challenge. This study investigates loss characteristics instability pump-turbine during operation using both model testing computational fluid dynamics methods. The results indicate that predominantly occurs guide vane (GV) passage draft tube (DT), more with flow reduction. Specifically, vaneless space linked to shear vorticity, while rigid vorticity plays prominent role GV DT. Analysis Rortex enstrophy transport equation shows pseudo-Lamb term dominant factor influencing vortex evolution. Additionally, combining Reynolds-averaged Navier–Stokes equations particle image velocimetry experiments reveals near zero-velocity gradient region, effects are concentrated core on runner side, primarily wake direction motion.

Язык: Английский

Progressive erosion investigation in elbow pipe: A quantitative assessment using dynamic mesh approach

Physics of Fluids, Год журнала: 2025, Номер 37(3)

Опубликована: Март 1, 2025

The study proposes a method for quantifying the progressive erosion in 90° elbow pipe with dynamic mesh technology, analyzing its impact on and flowing characteristics. findings reveal that depth count are primarily concentrated midsection of outer elbow, exhibiting elliptical “V-shaped” distributions, respectively, highest values observed minimum particle diameter 0.075 mm. angle demonstrates contraction-expansion trend, peaking at contraction zone, while velocity is higher elbow. As size increases, decrease, range angles broadens, maximum value shifts inward. Impact declines overall, though localized high persist. Over time, number pits wall increase. Maximum small medium particles, around 45°, whereas large particles cause near 60°. Material loss from increases linearly, but rate increase gradually diminishes. Large severe short-term material loss, contribute more over extended periods. Erosion-induced deformation causes abrupt changes fluid direction, intensifies vortex strength wall, high-pressure region toward deformed area, expands inner Furthermore, most critical parameter influencing depth. offer technical support quantitatively predicting sediment-induced provides guidance ensuring reliable pipeline operation.

Язык: Английский

Coherent structure analysis of double-helix vortex rope in pump turbine operating in turbine mode based on POD and DMD

Journal of Energy Storage, Год журнала: 2025, Номер 128, С. 117144 - 117144

Опубликована: Май 26, 2025

Язык: Английский