The 1000 MW Francis turbine unit at the Baihetan hydropower station is maximum capacity in world present, and it has adopted runner type with long short blades. For this ultra-high output turbine, especially breakthrough structure, hydraulic excitation phenomenon caused by internal dynamic static interference key factor for stability of unit. In study, taken as research object, rated conditions...

From the immersed boundary (IB) method point of view, the solid part may mainly act as elastic body or rigid body. Traditionally, the IB approach for fluid and rigid body interaction or fluid dynamics with complex geometry and boundary conditions has been divided into two main categories: the feedback forcing approach and the direct forcing approach. In the direct-forcing IB approach, the body ...

Abstract Francis turbines with medium or high specific speeds may experience a particular type of instability in the upper part load which precessing vortex has an elliptical shape. The occurrence part-load (UPLI) is accompanied by large-amplitude pressure fluctuations at distinct frequency between 2 and 4 times runner rotational speed. This paper experimentally investigates UPLI for reduced-sc...

In this paper, a numerical simulation to analyze the influence of the surrounding water in a turbine runner has been carried out using finite element method (FEM). First, the sensitivity of the FEM model on the element shape and mesh density has been analysed. Secondly, with the optimized FEM model, the modal behaviour with the runner vibrating in air and in water has been calculated. The added...

Francis turbines operate in many cases out of its best efficiency point, in order to regulate their output power according to the instantaneous energy demand of the grid. Therefore, it is of paramount importance to analyse and determine the unstable operating points for these kind of units. In the framework of the HYPERBOLE project (FP7-ENERGY-2013-1; Project number 608532) a large Francis unit...