EcoNavis to Validate and Demonstrate Improved Design for Wind Rotors
Scotland-based EcoNavis Solutions believes it has a technological innovation that can enhance the performance of wind rotors. With wind-assisted propulsion gaining increased interest, the company is using a Scottish Enterprise research grant to move its concept from the drawing board to validation and demonstration.
The basic concept of the wind rotor promoted by Anton Flettner in the 1920s remains largely unchanged after more than a century. The spinning rotor captures the energy of the wind to provide additional thrust for ships and has become one of several competing technologies in the sector.
EcoNavis, however, points out that there are limitations to the original technology that impact its reliability. Issues such as a change in wind direction can reduce the effectiveness and also mean that ships require more route planning to maximize the effectiveness of the technology.
The company has patented a tail-appendage device, which it says can increase thrust, reduce power demand, and widen the range of wind angles in which the rotor sail can operate efficiently. The tail enables the company to essentially broaden the rotor’s effective “wind window” and reshape the wind flow in the rotor’s wake.
It delivers higher thrust with lower torque demand. EcoNavis reports initial simulations indicate an increase in thrust of up to 10 percent with a 5 percent reduction in torque.
“Flettner rotors already offer one of the highest lift-to-drag ratios among wind-assisted devices, with a relatively modest footprint, but the main drawback has been the narrow band of wind angles – typically beam and stern-quarter winds,” said EcoNavis CEO and founder Dr. Batuhan Aktas. “By recovering energy that would otherwise be lost and optimizing the flow behind the rotor, we can provide a Flettner rotor design with a greater operational range.”
The fixed aerodynamic appendage downstream helps to stabilize the airflow behind the rotor. The company says it will permit the rotor to continue to generate thrust as wind conditions change.
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By recovering energy that would otherwise be lost and optimizing the flow behind the rotor, EcoNavis believes its EcoRotor Sail can offer greater operational range. It says shipowners can have greater flexibility in route planning and more consistent performance over a typical trading year without fundamental changes to vessel operations.
The next phase will move into physical testing. Development of the EcoRotor Sail is being backed by a £100,000 ($133,000) research grant from Scottish Enterprise to take the £265,000 ($352,000) project through to validation and demonstration stages.