Experiments and Numerical Simulations of the Flow Within a Model of a Hydraulic Turbine Surge Chamber

Surge chambers are sometimes included in the hydraulic circuits of hydroelectric power plants as a means of absorbing pressure waves formed by the opening/closing of a turbine. Surge chambers, however, result in additional power loss and therefore reduce the efficiency of the plant. This work aims to 1) investigate the physical phenomena and flow within a surge chamber under normal operation (i.e. no opening/closing of a turbine), and 2) obtain experimental data for the validation of numerical simulations of this complex flow.;Overall agreement between the experimental and numerical quantities is good, although there are local discrepancies. The periodic oscillations of the flow observed in the experiments and the numerical simulations of the simplified model (operated under constant input flow rate) were associated with the phenomena of i) oscillating mass, and ii) self-induced sloshing.;Experiments and numerical simulations have been conducted for a simplified model of a surge chamber operated under multiple configurations at a constant input flow rate. This 3-D, unsteady, incompressible, swirling, two-phase flow has been experimentally characterized by global values, such as head losses, and local values, such as free-surface profiles, free-surface oscillations, reduced pressure profiles and velocity fields. The same quantities were also obtained numerically using the "rasInterFoam" solver of the open source code "OpenFOAM-1.5," for incompressible two-phase flows. This solver implements a one-fluid, volume-of-fluid (VOF) method with an interface-capturing scheme.