Experimental and Numerical Analysis of a Cross-Flow Turbine

Abstract

An important component of the management cost of aqueducts is the energy costs. Part of these costs can be recovered by transforming some of the many existing energy dissipations into electric energy by means of economical turbines. This paper describes an experimental study that has been carried out in order to (1) test the performance of an economical cross-flow turbine that maintains high efficiency within a large range of water discharges, and (2) validate a new approximate formula relating main inlet velocity to inlet pressure. It is demonstrated that the proposed formula, on the basis of some simplifying assumptions, exactly links inlet velocity to inlet pressure with any possible geometry of the cross-flow turbine. A specific facility was designed and constructed inside the hydraulic laboratory of the Dipartimento di Ingegneria Civile, Ambientale, Aerospaziale dei Materiali (DICAM) Department of the University of Palermo to carry out the experiments. Both numerical and experimental tests were carried out for the two cases of turbine impeller with and without the internal shaft. Experimental and numerical results showed a good agreement and give an excellent validation of the proposed formula, which can be readily used for a fast and reliable design of a cross-flow turbine.