Marine turbocharger could cut engine noise and raise efficiency

Reducing sound waves at sea

25 February 2010 | By Ellie Zolfagharifard

University College London (UCL) has undertaken a project that could lead to a turbocharger design that is low in noise and high in fuel efficiency.

The research, led by Prof Mehrdad Zanganeh, focuses on the design of turbochargers for marine applications – an area that is subject to ever-stricter noise standards.

Current noise-reduction methods involve fitting filter silencers to compressor intakes. These limit the pressure ratio of the turbocharger and consequently prevent improvements in fuel efficiency and power density.

While noise is a growing concern, the industry is also being urged to increase fuel efficiency and reduce NOx emissions. However, increasing the efficiency means increasing the speed of the engines, which in turn creates more noise.

To overcome these conflicting challenges, the team at UCL is working on a noise-control method that uses aero-acoustic models alongside data from 3D inverse-design methods.

’In our approach we specify the pressure distribution on the blade shape and combine that with noise data,’ explained Zanganeh. ’This will help us to pinpoint the optimum balance between noise and efficiency and hopefully lead to much more innovative designs.’

The inverse design methods allow engineers to specify a pressure distribution on the blades and then use computational tools to provide the geometry of the blades that will result in the desired pressure distribution.

Zanganeh believes that by combining this method with aero-acoustic modelling, it could be possible to reduce noise by as much as four decibels and improve efficiency by two to three per cent.

If the research is successful, the resulting design will be manufactured by Napier Turbochargers and will be tested at Napier’s facility in Lincoln.