In course of a refurbishment project, we designed new guide vanes and a new 6-blade Kaplan runner for a hydro-project in India. The performance data predicted by means of 3D CFD-simulations were proven with a model test.
In addition to the results gained so far, a transient analysis of the improved units was carried out.
The aim was to estimate the minimum closing time of the wicket gate required to keep the speed rise of the turbine as well as the pressure rise in the spiral and penstock within the given limitations.
The 1D-transient-simulations were carried out by applying the “Method of Characterstics” in combination with hydropower models developed by Jaberg & Partner.
To model the hydraulic and transient behaviour of the turbines, the hill chart estimated in course of the model test provides all necessary information to calculate the dynamic behaviour in terms of runaway speed, pressure rise and wicket gate closing time.
A solution was found in a linear closing of the wicket gate and applying an end-of stroke damping for very low guide vane openings.
Find out more about the successfully implemented design and model test for the Kaplan turbine.