In-flight icing simulation on engine nacelles

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2017
Uğur, Nermin
In-flight ice accumulation on airframes may lead to great risks for flight safety due to aerodynamic performance degradation, loss of control, engine rollback and increase in weight. Certification concerns become an important topic when flight safety is considered. To prove that an aircraft can fly safely in certain icing conditions, authorities like FAA and EASA have defined meteorological conditions. Flight tests, laboratory tests and numerical simulations are the methods utilized to show compliance with icing related certification requirements. Besides certification purposes, design of an anti/de-icing systems requires predictions of accumulated ice mass on airframes and its impingement limits for given flight conditions. The present study aims to develop a computational tool for icing simulations on engine nacelles. The code is written in FORTRAN language and mainly consists of four modules: flow field solution with panel method, droplet trajectory and collection efficiency calculations using Lagrangian approach, thermodynamic analysis for heat transfer coefficient calculations and ice accretion model with Extended Messinger Model. Icing analyses on two-dimensional wing and engine intake geometries are performed with the developed tool. The results are validated with experimental and numerical data available in literature. Ice shape predictions, collection efficiency and heat transfer coefficient results obtained in the current study are mostly in good agreement with reference results for airfoil and axisymmetric engine intake cases. On the other hand, for non-axisymmetric engine intake geometries, two-dimensional approach is found insufficient when ice shape and impingement limit results are considered. In order to obtain more accurate ice shapes formed on non-axisymmetric engine intakes, three-dimensional approach is suggested despite higher CPU time. 
Citation Formats
N. Uğur, “In-flight icing simulation on engine nacelles,” M.S. - Master of Science, Middle East Technical University, 2017.