A Bilayer Sensor System for Measuring Air Flow

A bilayer magnetostrictive sensor is inserted into a cylindrical tube where air flows at a controlled rate. A circuit connected to the sensor conveys a signal that arises from changes in frequency as a function of displacement using the frequency modulation principle. The performance of the sensor was tested at air stream speeds up to 25 m/s and at a range of distances from the center of the tube. The acquired response of the sensor was compared against a displacement simulation model designed using the Comsol Structural Mechanics package. The results demonstrate that this system provides a robust solution to the problem of monitoring variable airflows as needed by the automotive and biomedical industry