Constellation, le dépôt institutionnel de l'Université du Québec à Chicoutimi

Résumé

De/anti-icing fluids are used on aircraft prior to takeoff to remove ice and prevent its formation. The applied fluids have a freezing point at least 7°C lower than the air temperature, to accommodate incoming precipitation, evaporation, and error. However, although most of applied fluids flow off prior to takeoff, it is possible that ice-contaminated residual fluid freezes upon rotation due to the temperature decrease created by the pressure drop over the top of the wing. A couple of first person accounts of snow/fluid freezing upon aircraft rotation have been documented. Therefore, because this problem does not respect the clean wing concept at takeoff, AMIL (Anti-Icing Materials International Laboratory) was interested to see how it could happen. To address this problem, the CIRAMIL 2D in-flight icing model was adapted to simulate these particular conditions that may occur at takeoff. The model was recently developed and validated with data obtained in wind tunnel and other numerical codes (LEWICE-2D and CIRA-2D). This paper describes the basic model and discusses the assumptions and icing mechanisms, which are applied to a few icing cases simulated on the NACA0012 and Boeing 737-200 airfoils. Numerical results show, given the fluid has the same behavior as water, that the anti-icing fluid can locally freeze on small patches of the wing where the fluid is sufficiently diluted by water.