Lasers to clean and measure jet turbine blades

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Lasers are to be used to clean and measure the condition of jet engine turbine blades for improved propulsion efficiency.

Jet engines accumulate a lot of dust and other contaminants because they suck in huge amounts of air and these particles coat the turbine’s blades. Researchers at the University of Connecticut developed a method to use a pulsed laser to remove the layer of contaminants, without damaging the underlying ceramic coating or the blades. The particles fluoresce when struck by the laser beam and users can tell when all the contaminants are gone because there is no more fluorescence.

Michael Renfro is the University’s United Technologies associate professor of engineering innovation and associate head of the Department of Mechanical Engineering. Renfro said: ‘The contaminant on the turbine blades is very irregular. In some places it’s very thick and in others it’s very thin. So if you tried to sand it off you would damage the ceramic coating itself.’

The ability of lasers to make materials fluoresce is also being exploited by the University’s researchers to measure the stress and damage in turbine blades’ ceramic coatings. The bonding material between the coating and the metallic blades will fluoresce under laser light. The fluorescence can be measured and that measurement will show how strong the bond is, how much viable coating is left, and whether the blade is damaged and prone to failure. Renfro and his colleagues are working to make this technology portable so it can be used to analyse engines when they are still attached to the wing.

The ceramic coating research is being funded by the US government National Science Foundation and turbine manufacturer Rolls Royce.