Measurement of Ice Accretion Using Ultrasonic Pulse-EchoTechniquesAircraft icing remains one of the most severe aviation weather hazards. A system to measure aircraftice accretion and accretion rate in real time could directly reduce this hazard. Real-timemeasurement of ice accretion rate can provide the pilot with a quantitative evaluation of icingseverity. Therefore, the effectiveness of changes in flight path to minimize ice accretion can bedetermined. In addition, an automatic measuring system system measuring ice accretion on criticalcomponents such as wings, engine inlets, propellers, or rotor blades could be used to automaticallyactivate and optimally control ice protection systems. Although many schemes have been suggestedfor measuring aircraft ice accretion,1-3 there is still a need for a practical systemcapable of real-time in situ measurement of ice accretion. The purpose of this studyis to evaluate the feasibility and potential performance of an ice detection system using pulsedultrasonic waves to measure ice thickness over a small transducer mounted flush with the aircraftsurface. Since the technique of ultrasonic "pulse-echo" thickness measurement produces a real-timeice thickness signal, the ice accretion rate may be determined by electronically differentiating thisthickness measurement with respect to time.
--J. Hansman, Jr., and M. S. Kirby, "Measurement of Ice Accretion Using Ultrasonic Pulse-EchoTechniques," Proceedings, American institute of Aeronautics andAstronautics
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