Water hammer investigation of shut-down of high-head hydropower plant at very high Reynolds number flows

english

2019

volume 65, issue 7/8

emergency shut-down   high Reynolds number   high-head hydropower plants   Pelton turbine   water hammers

Univerza v Ljubljani, Fakulteta za strojništvo
(Obvezni izvod spletne publikacije)

This paper investigates water hammer phenomena in a refurbished high-head hydropower plant Perućica, Montenegro during shut-down of the entire plant - simultaneous closure of the seven Pelton turbine units. In-situ measuring campaign during a number of steady and unsteady conditions has been performed on the plant's open channel, pressurized and tail race sub-systems with primarily goal to define measures that will enable achievement of the plant's installed capacity. In-house software written in Visual Fortran and based on the method of characteristics (MOC) has been developed. Closure of the Pelton turbine distributors is modelled by the two-speed closing law. Dissipation torques in turbine housing and shaft bearings are considered in calculation of the Pelton turbine unit rotational speed change. Numerical results given for standard quasi-steady and convolution based unsteady friction model are compared with results of measurements at flows with very high initial Reynolds numbers (larger than 10^7). Developed numerical model shows good agreement with the results of site measurements. It is shown that the unsteady friction has a small impact on pressure histories in Perućica HPP.

06.08.2019