Work

Water Hammer Caused by Needle Valve Closure in Micro Hydropower Pelton Penstocks: Choosing the Closure Time

Year: 2026

Type: conference-paper

Abstract: The paper examines how fast the needle of a micro-hydro Pelton turbine may close without excessive water hammer. A reservoir–penstock–nozzle system was simulated with the method of characteristics (MOC) for four hypothetical sites (H = 25–200 m, steel and HDPE pipes). The results were compared with the Joukowsky, Michaud and rigid-column formulas. Fast closure raises the head by 0.97–2.30 H0. For a 20 % surge, the rigid-column formula underestimates the closure time by 1–37 % and Michaud’s formula overestimates it by 34–81 %. A closure time of 1.4 times the rigid-column value is enough for a linear needle; about 2.0 times is needed when the nozzle area changes only over the last 70 % of the stroke.

Source: Zenodo (CERN European Organization for Nuclear Research)

DOI: 10.5281/zenodo.23399652

Author: Alokhanov, Ulugbek

Institution: Tashkent Institute of Irrigation and Agricultural Mechanization Engineers

Language: English

Topic: Water Systems and Optimization

Subfield: Civil and Structural Engineering

Field: Engineering

Domain: Physical Sciences

Open Access status: green

OpenAlex ID: W7221954631

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