OPTIMAL DESIGN AND EXPERIMENTAL VALIDATION OF A TURGO MODEL HYDRO TURBINE

This work presents the development and application of a new optimal design methodology for Turgo impulse hydro turbines. The numerical modelling of the complex, unsteady, free surface flow evolved during the jet-runner interaction is carried out by a new Lagrangian particle method, which tracks a number of representative flow elements and accounts for the various hydraulic losses and pressure effects through special adjustable terms introduced in the particle motion equations. In this way, the simulation of a full periodic interval of the flow field in the runner is completed in negligible computer time compared to the corresponding needs of modern CFD software. Consequently, the numerical design optimization of runner geometry becomes feasible even in a personal computer and affordable by small and local manufacturers. The bucket shape of a 70 kW Turgo model is properly parameterized and numerically optimized using a stochastic optimization software to maximize the hydraulic efficiency of the runner. The optimal runner and the rest turbine parts are then manufactured and installed in the Lab for testing. Detailed performance measurements are conducted and the results show satisfactory agreement with the numerical predictions, thus validating the reliability and effectiveness of the new methodology.