Analysis of unstable flow characteristics in the blade region of Francis pump-turbine under non-design conditions

Physics of Fluids, Journal Year: 2025, Volume and Issue: 37(1)

Published: Jan. 1, 2025

Under non-design situations, the Francis pump-turbine, a frequently employed core energy conversion device in pumped storage power plants, plays significant role ensuring their stable operation. This article examines unstable flow inside pump-turbine using gradient theory and numerical computations model experiments. Research has indicated that forced impacts separation between fluids blades are causes of deteriorating mechanical gradients, whereas non-optimal angles stay guide vanes can readily cause separation. The strong helical at blade inlet is primary flow, hub outlet locations for high shear force work area brought on by large-scale vortex structures, middle portion impeller where field begins needs more attention.

Language: Английский

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Study on pressure field characteristics of high specific speed axial flow pump under full working conditions based on wavelet transform

Physics of Fluids, Journal Year: 2025, Volume and Issue: 37(2)

Published: Feb. 1, 2025

Axial flow pumps are widely used in ship jet propulsion units and coastal plain pumping stations. In the actual operation process, axial need to operate extreme working conditions, order explore safety stability of operating under special this paper adopts a method that combines model experiment numerical simulation. A full-condition pump section (AFPS) is carried out on high-precision system test platform. Meanwhile, simulation predicting full characteristics AFPS constructed. Numerical simulations for at 31 rates, hydrodynamic investigated depth 8 which reveals internal evolution synergistic influence water direction impeller steering whole quadrant. The traditional analysis Fast Fourier Transform difficult analyze dynamic changes such complex non-smooth signal field conditions pumps. paper, wavelet transform pressure pulsation signals time–frequency two-dimensional plane multiple scales, capture subtle changes, cross relationships different locations, comprehensively deeply spatiotemporal transformation section. results show when opposite rotation impeller, disordered strong. Except forward turbine condition rotating (OP4) condition, energy inlet greater than outlet with maximum difference eight times (OP5). between has large number common frequencies.

Language: Английский

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Study of energy dissipation mechanisms and pressure pulsation spectrums in a vertical axial flow pumping station on the ultra-low head condition based on multiple analysis methods

Energy, Journal Year: 2025, Volume and Issue: unknown, P. 135227 - 135227

Published: Feb. 1, 2025

Language: Английский

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Steam-side irreversible loss analysis of spirally corrugated tube

Energy, Journal Year: 2024, Volume and Issue: unknown, P. 133860 - 133860

Published: Nov. 1, 2024

Language: Английский

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