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Aircraft icing refers to the ice buildup on the surface of an aircraft flying in icing conditions. The ice accretion on the aircraft alters the original aerodynamic configuration and degrades the aerodynamic performances and may lead to unsafe flight conditions. Evaluating the flow structure, icing mechanism and consequences is of great importance to the development of an anti/deicing technique. Studies have shown computational fluid dynamics (CFD) and machine learning (ML) to be effective in predicting the ice shape and icing severity under different flight conditions. CFD solves a set of partial differential equations to obtain the air flow fields, water droplets trajectories and ice shape. ML is a branch of artificial intelligence and, based on the data, the self-improved computer algorithms can be effective in finding the nonlinear mapping relationship between the input flight conditions and the output aircraft icing severity features.
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Airborne Platform for Ice-Accretion and Coatings Tests with Ultrasonic Readings (PICTUR)
Hazardous atmospheric icing conditions occur at sub-zero temperatures when droplets come into contact with aircraft and freeze, degrading aircraft performance and handling, introducing bias into some of the vital measurements needed for aircraft operation (e.g., air speed). Nonetheless, government regulations allow certified aircraft to fly in limited icing environments. The capability of aircraft sensors to identify all hazardous icing environments is limited. To address the current challenges in aircraft icing detection and protection, we present herein a platform designed for in-flight testing of ice protection solutions and icing detection technologies. The recently developed Platform for Ice-accretion and Coatings Tests with Ultrasonic Readings (PICTUR) was evaluated using CFD simulations and installed on the National Research Council Canada (NRC) Convair-580 aircraft that has flown in icing conditions over North East USA, during February 2022. This aircraft is a flying laboratory, equipped with more than 40 sensors providing a comprehensive characterization of the flight environment including measurements of temperature, pressure, wind speed and direction, water droplet size and number distribution, and hydrometeor habits imagery. The flight tests of the platform included assessment of passive icephobic coatings as well as heat-assisted tests. Monitoring tools included visual high resolution, real-time inspection of the surface as well as detection of surface ice using NRC’s Ultrasonic Ice Accretion Sensors (UIAS). In this paper, we present the new platform and show some preliminary commissioning results of PICTUR, collected inflight under, predominantly, supercooled small droplets and supercooled large drops (SLD) icing conditions. The combination of the platform and the complementary sensors on the aircraft demonstrated an effective and unique technique for icing studies in a natural environment.
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- Award ID(s):
- 2113995
- PAR ID:
- 10447629
- Date Published:
- Journal Name:
- SAE Technical Paper Series
- Volume:
- 1
- ISSN:
- 0148-7191
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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There is growing interest in government and industry to use numerical simulations for the Certification by Analysis of aircraft ice protection systems as a cheaper and more sustainable alternative to wind-tunnel and flight testing. The ice accretion on a cylindrical test article mounted under the wing of the National Research Council of Canada’s Convair-580 research aircraft during a flight test in Appendix O icing conditions was simulated using Ansys FENSAP-ICE™. A multishot simulation with input parameters averaged over the full icing period led to an increased level of liquid catch and ice accretion (by mass), and a broader ice profile when compared to a simulation with shot-averaged input parameters. An additional simulation using Ansys’ proprietary “extended icing data with vapor solution” method for calculating heat fluxes at the icing surface resulted in a broader ice profile in comparison to the classical technique, which produced a similar amount of accretion by mass. No combination of simulation settings, input parameters, and multishot methods tested in this study generated the same level of surface detail observed during flight testing, however, the amount of ice accretion, general location of ice features, and formation processes were in good agreement with the experimental results.more » « less
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Abstract Aircraft icing, resulting from the freezing of supercooled water droplets on exposed surfaces, presents considerable hazards to flight safety by impairing aerodynamic performance and operating efficiency. This study empirically examines the interaction dynamics of supercooled water droplets and dielectric barrier discharge (DBD) plasma actuators, emphasizing electrical, thermal, and phase transition phenomena. Supercooled droplets were produced via sonic levitation in a freezer set at −10°C and subsequently deposited onto the plasma actuator surface at −5°C. Electrical diagnostics indicated a reduction in current intensity following droplet impact which inhibited plasma discharge activity. Thermal imaging detected localized heating at nucleation locations, indicating a temperature plateau during freezing caused by latent heat release. A study of spatial temperature along the droplet x-axis revealed a pronounced thermal gradient, with the most significant temperature rise occurring adjacent to the plasma-exposed area. High-speed imaging elucidated droplet dynamics, demonstrating spreading, descent towards the ground electrode, and subsequent retraction following stabilization. These discoveries improve the comprehension of plasma-droplet interactions, aiding in the improvement of plasma-based anti-icing technology. This research promotes the creation of effective and environmentally friendly solutions for aviation safety and other areas affected by icing hazards.more » « less
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Abstract The presence of supercooled water in polar regions causes anchor ice to grow on submerged objects, generating costly problems for engineered materials and life-endangering risks for benthic communities. The factors driving underwater ice accretion are poorly understood, and passive prevention mechanisms remain unknown. Here we report that the Antarctic scallop Adamussium colbecki appears to remain ice-free in shallow Antarctic marine environments where underwater ice growth is prevalent. In contrast, scallops colonized by bush sponges in the same microhabitat grow ice and are removed from the population. Characterization of the Antarctic scallop shells revealed a hierarchical micro-ridge structure with sub-micron nano-ridges which promotes directed icing. This concentrates the formation of ice on the growth rings while leaving the regions in between free of ice, and appears to reduce ice-to-shell adhesion when compared to temperate species that do not possess highly ordered surface structures. The ability to control the formation of ice may enable passive underwater anti-icing protection, with the removal of ice possibly facilitated by ocean currents or scallop movements. We term this behavior cryofouling avoidance. We posit that the evolution of natural anti-icing structures is a key trait for the survival of Antarctic scallops in anchor ice zones.more » « less
- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Conference Paper:
- https://doi.org/10.4271/2023-01-1431
