Guilherme Moreira Grossi’s scientific contributions

The present paper shows the state of the art on this topic, within the framework of a research project in a 1:70 physical type-model implemented at the Center of Hydraulics and Hydrology Prof. Parigot de Souza (CEHPAR/LACTEC); located in the Campus III of the Federal University of Parana (UFPR). The aim of the study is to study and identify combinations between hydrodynamic conditions from 3D-submerse flow and geometric factors of the bottom side conduits. The consulted literature review leads to conclude that the available premises relates mostly to 2D-flow behavior in the downstream evacuating channel are seldom present, where the existing equations describe the phenomenon arguably well. However, for discharges with significant depths downstream the hydropower unit, observed and calculated ejection values from laboratory tests show remarkably large differences, being more detailed research needed.

The aim of this research is to complement and improve the results about ejection effect in a low-head hydropower plant from a previous study in physical models and to evaluate the effect of ejection on the turbine power and efficiency, in the model alternative with the best performance. The study covers four additional geometric alternatives, aside from the original design and the six already tested alternatives in that study, using 1:70 scale model tests. Three approaches were considered: (1) The development of a theoretical equation for the ejection effect, based on the equations of conservation of momentum and energy, (2) An assessment of an empirical relationship for the effective ejection using dimensionless flow parameters from 521 flow scenarios and (3) The development of two empirical relationships between the effective ejection and the power and efficiency increments of the HPP turbines (63 flow scenarios).