Experimental study of Cross-Flow micro-turbines for aqueduct energy recovery

An important component of the management cost of aqueducts is given by the energy costs. Part of these costs can be recovered by transforming some of the many existing energy dissipations in electric energy by means of economic turbines. In this study an experimental work has been carried out: 1) to test the performance of an economic Cross-Flow turbine which maintains high efficiency within a large range of water discharges, and 2) to validate a new approximated formula relating main inlet velocity to inlet pressure. It is proved that the proposed formula, according to some simplifying assumption, exactly links inlet velocity to inlet pressure according to any possible geometry of the Cross-Flow turbine. A specific stand has been designed and constructed, inside the lab of the DICAM Department of the University of Palermo, to carry on the experiments. Results show a general good agreement between numerical simulation and results and a bit larger experimental efficiency values. The ratio between the inlet experimental velocity and the velocity provided by the new formula is almost constant with respect to the velocity ratio and falling in the range between 0.95 and 0.98.