PREDICTION OF ICE ACCRETION AND CFD ANALYSIS OF NACA 2412 AIRFOIL FOR EVALUATION OF AERODYNAMIC PERFORMANCE DEGRADATION

Abstract

High altitude flights possess significant icing hazard in certain type of atmospheric conditions. This ice accretion on aircraft wing leading edges and engine nacelle pose threat to the flight safety. From early days of beginning of high altitude flights, numerous studies have been undertaken to determine the effects of icing on aircraft performance. Bangladesh is now moving at galloping pace in the aviation industry, and is expected to take leap of high altitude flight designs in near term period. This could be accomplished if several technologies are developed in-house prior to design and development of high altitude flights. One such requirement is the development of code for prediction of ice accretion and subsequently to design the anti-icing system. With this long term goal in mind, the present research focuses on understanding of the analytical approaches to predict ice accretion physics on aircraft wing cross section. Using the existing ice accretion thermodynamic and other conservation laws presented in open literature, a computer code was developed to predict the ice accretion over the airfoil. The code developed was validated against the experimental ice shapes from the open literatures. Using the developed code, the ice accretion prediction is undertaken on a specific airfoil i.e. NACA 2412, a most common airfoil cross section for moderately high altitude flights. The aerodynamic performance of the predicted ice accretion was analyzed using the Computational Fluid Dynamic (CFD) technique. The aerodynamic study was undertaken for three different icing conditions and it suggests that the ice accreted airfoil possesses lower lift than the base airfoil. It is also observed that the increase in the drag for ice accreted airfoil is significant as compared to base airfoil. Results of the study show that, most critical and worst icing occurs in presence of altocumulus clouds forming mixed ice on the airfoil leading edges. Such icing conditions result in reduction in lift coefficient and increase in drag coefficient approximately by 90% and 800% respectively compared to the base airfoil. These observations are in consonance with the published literature available in open domain. The current research is considered as the stepping stone for subsequent development and improvement of icing codes as well as design of anti-icing systems.