Propeller research aims to improve ships’ fuel efficiency

Ships could become more fuel efficient and comfortable for passengers with research being undertaken by Chalmers University of Technology for Rolls-Royce.

Researchers at the Swedish university, led by Professor Lars Larsson, are using computational fluid dynamics to predict the pressure around ships’ propellers, which in turn affects the fuel efficiency of the ship itself, by altering the pressure around the hull.

Propeller designers at Rolls-Royce will begin using the numerical methods developed at Chalmers later this year, said Larsson, head of the department of naval architecture and ocean engineering at the university.

‘The methods will result in better propeller designs. It may not be obvious to the naked eye, but the efficiency of the propellers will be higher, so the power required to drive the ship will be lower, and the amount of fuel required will be lower.’

This greater efficiency could be used either to reduce fuel consumption or to increase the speed of the vessel, said Larsson. ‘But most ship manufacturers will be looking for reduced fuel consumption, because often journey times are less important,’ he said.

Traditionally shipyards design vessels, and propeller manufacturers design the blades. In contrast the Chalmers project will develop a tool to look into the interaction between the propeller and the hull, said Patrik Kron, manager of the Rolls-Royce Hydrodynamics Research Centre.

Pressure around the propellers also produces noise and vibrations that are felt by passengers on board the ship. So better propeller design could lead to more comfortable journeys, said Kron. ‘Ship design is often a compromise between fuel efficiency and the noise and vibration levels on board. With this prediction tool we can improve both.’

The team also plans to extend the project to include cavitation, where rapid pressure changes in the water create bubbles. When the bubbles implode they produce shockwaves in the water which can have a highly damaging effect on a ship’s components.

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