Bearing monitor

US researchers have developed sensors resilient enough to survive the harsh conditions inside jet engines.


Researchers at Purdue University, working with the US Air Force, have developed tiny MEMS-based wireless sensors resilient enough to survive the harsh conditions inside jet engines. They could be used to detect when critical bearings are close to failing and prevent breakdowns.


‘The MEMS technology is critical because the sensors need to be small enough that they don’t interfere with the performance of the bearing itself,’ said Farshid Sadeghi, a professor of mechanical engineering. ‘And the other issue is that they need to be able to withstand extreme heat, because engine bearings must function at temperatures of about 300oC.’


The new MEMS sensors provide early detection of impending failure by directly monitoring the temperature of the engine bearings, whereas conventional sensors work indirectly by monitoring the temperature of engine oil, yielding less specific data. Since they are powered by inductive coupling, the MEMS devices do not require batteries and transmit the temperature data wirelessly.


‘This kind of advance warning is critical so that you can shut down the engine before it fails,’ said Dimitrios Peroulis, an assistant professor of electrical and computer engineering.


The sensors could be in use in a few years in military aircraft such as fighter jets and helicopters.