Development and optimization of dual-mode propellers for renewable energy

Propeller as both propulsion and turbine device has been used for many marine vehicle renewable energy applications, especially for sailing boats and yachts. However, dual-mode propellers in these applications were mainly selected from off-the-shelf with little or no hydrodynamic performance optimization coupling propulsion and energy generation efficiency on the same rotor. To address this issue and provide some scientific evidence and data for the design of the towed propeller shaft alternator, a dual-mode rotor series, as an example, in terms of a balanced propulsion and energy generation were evaluated and optimized. Previous experimental data for these rotors was used for code validation, to ensure a reliable and accurate prediction of the effects of pitch and solidity on performance. The results obtained indicate that the optimized fixed pitch propeller could perform as propulsion and tidal/current turbine with a balanced efficiency in both modes for low speed ships, especially for yachts. The balanced relatively high power productivity and propulsive performance are achievable for low speed ships anchored in a current or a regular sail boat for which a propeller is used as a towed turbine.