Hidrodynamic and performance of low power turbines : conception , modelling and experimental tests

The present work comprises a research about hydraulic machines with the aim of optimization and the selection of adequate turbines of low power for exploitation of an available energy still unexplored in water supply systems based on analyses of 3D hydrodynamic flows and on characteristic curves which lead to the best efficiency point. The analysis is carried out based on non-dimensional parameters (i.e., discharge, head, efficiency, runner speed and mechanical power) in order to be possible comparisons. Mathematical models based on the physical principles, associated to the development of volumetric and rotordynamic machines, are developed. New turbines are suggested, which are based on similar theory among turbo machines based on applications in hydraulic systems with guarantee discharge and available head. The hydrodynamic fluid mechanical analysis requires the use of complex advanced models (CFD) which apply the equations of Navier-Stokes by using mathematical models of conservation laws, for the study of the turbulent flow behaviour. To determine the correlation between the flow velocity and pressure fields, the kmodel, is used in this research. Many turbines are evaluated (i.e., positive displacement (PD), pump as turbine (PAT), propeller with volute at inlet, four and five blades tubular propellers) and sensitivity analyses, to the best configurations, as well as comparisons between performance curves and experimental tests. Results are presented with the appropriate range variation for each turbine type and application.