A novel approach, which is capable of characterizing different types of ice accretion, was developed by leveraging the significant discrepancies in attenuation characteristics of ultrasonic waves traveling in different ice types (i.e., rime or glaze). While the theories of acoustic attenuation in pulse-echo configuration for a multilayer structure were formulated, a feasibility study was also performed to demonstrate the ultrasonic-attenuation-based technique to characterize two different types of ice samples representative of typical rime and glaze ice accretion seen over airframe surfaces. Significant differences were found in the ultrasonic attenuation characteristics between the two compared ice samples over the frequency range of 5–15 MHz. The attenuation coefficients of the rime-like ice sample were found to be much greater than those of the glaze-like ice sample at any given ultrasonic frequencies. While the values of ultrasonic attenuation coefficients would increase with ultrasonic frequency for both the ice samples, the attenuation coefficients of the rime-like ice were found to have a much greater increasing slope (i.e., dα/df) and wider scattering range than those of the glaze-like ice. Such information could be used to develop ice-type-specific de-icing systems to reduce de-icing operational costs for aircraft operation in cold climate.
Ultrasonic-Attenuation-Based Technique for Ice Characterization Pertinent to Aircraft Icing Phenomena
2017
Aufsatz (Zeitschrift)
Englisch