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Shah, Aaryaman V.

University of British Columbia

Ice accretion on aviation surfaces imposes operational and safety challenges, severely impacting critical flight structures and equipment. For optimized ‘smart’ de-icing systems of the future, microwave resonant-based planar sensors are proposed for their high sensitivity to icing and versatility in integration. This thesis presents five microwave resonant sensors for ice sensing under simulated real-world icing conditions. Three planar ice sensors are designed for harsh roadway environments. A Split-Ring Resonator (SRR) sensor (1.2 GHz) is tested for sensitivity to icing with protective epoxy coatings. A complementary split ring resonator (CSRR) sensor with a robust epoxy-coated 1mm-thick aluminum build (1.18 GHz) monitors snow accretion. Asymmetric stripline CSRR sensors with increased shielding are implemented for exploratory time-domain-reflectometry measurements, for wired large-area sensor networks. A conformal single-port dual-frequency SRR sensor (1.9-2.2 GHz) was integrated onto a NACA 0018 airfoil with electrothermal de-icing capabilities to sense in-flight ice crystal icing (ICI). Tested in the National Research Council’s (NRC’s) Research Altitude Test Facility (RATFac) at 19,000 ft, 100 m/s, +3°C and melt ratios of 11%, 13%, 16% and 25%, the sensor differentiates %melt while monitoring de-icing and anti-icing processes. Icing on smaller Unmanned Aerial Vehicles (UAVs), drones, and electric vertical take-off and landing (eVTOL) crafts impact aerodynamics and weight, severely limiting operation. A novel multi-frequency SRR sensor (2-4 GHz) is integrated with a zone-based electrothermal de-icing system and a low interfacial-toughness coating on a NACA 0012 airfoil for location-specific accretion monitoring and zone-based ‘smart’ de-icing. Tested at the Anti-Icing Materials International Laboratory’s (AMIL) icing wind tunnel at varying LWC (0.3, 0.5 and 0.8 g/m3), airspeed (20 and 40 m/s) and temperature (-5°C: glaze, -10°C: mixed, and -20°C: rime) conditions, the sensor monitors ice accretion, tracking the real-time resonant frequency response with a maximum sensitivity of 179 MHz/mm. A fitted time-constant is found to be inversely proportional to increasing ice thickness, facilitating icing rate measurement and ice thickness prediction using real-time microwave sensors. This work represents a significant advancement in the field of microwave SRR ice sensing technology, bringing it one step closer to practical implementation as integrated location-specific ice sensors for ‘smart’ ice protection systems (IPSs).

Text

2024-12-20

Attribution-NonCommercial-NoDerivatives 4.0 International

http://hdl.handle.net/2429/87469

Electrical Engineering

University of British Columbia

UBCO

http://creativecommons.org/licenses/by-nc-nd/4.0/