Wärtsilä pre-swirl stator promises improved fuel efficiency

07 Nov 2017
EnergoFlow in combination with an optimised fixed pitch propeller can improve fuel efficiency by a further 2%

EnergoFlow in combination with an optimised fixed pitch propeller can improve fuel efficiency by a further 2%

Technology group Wärtsilä has launched a pre-swirl stator, EnergoFlow, that it claims can offer fuel reductions of up to ten percent, with a payback time of less than two years.

The device, comprising three fins connected by an outer ring to eliminate tip vortexes, optimise the inflow of water to the propeller to reduce power losses. The next-generation pre-swirl stator is the result of years of research and experimentation with hydrodynamics, energy-saving propulsion efficiency concepts and pre-swirl models.

Tamara de Gruyter, vice president, Wärtsilä Propulsion System Services, said: "As the result of increased propulsive efficiency and subsequent energy savings, Wärtsilä EnergoFlow reduces the emissions of ships. Investments in energy-efficient solutions ensure cost savings, compliance with maritime regulations and reduced environmental footprint."

The Wärtsilä device builds on early models developed under the EU-funded GRIP (Green Retrofitting through Improved Propulsion) project, with Wärtsilä and testing facility Marin taking up where that project left off two years ago. Versions for controllable pitch propellers and twin-screw arrangements are under development.

The system offers the greatest fuel economies for ships with full forms (high block coefficients) such as tankers and bulk carriers, which can achieve fuel savings of up to 10%. More streamlined vessels such as containerships can achieve savings of around 4%, although the payback time remains similar due to the greater amount of fuel used by these ships.

The company estimates that the lead time for the product - including optimisation to the hull form, CFD analysis and installation -will be around six months. The stator, which has been extensively model tested with Marin, is being launched commercially at the Europort exhibition in Rotterdam this week.

NOTE: A full report on the innovative development process behind EnergoFlow will appear in the December issue of The Motorship, out next month.